A method for reconstructing pressure field, a method for determining downhole complexity and a device

Abstract

The present invention discloses a method for reconstructing a pressure field, a method for determining downhole complexity, and a device. The method comprises: calculating the well depth and the fluid circulation time in the well corresponding to each pressure measurement point of the pressure measurement chip tool, calculating the theoretical wellbore pressure values ​​corresponding to the well depths of different measurement points, and obtaining the measurement point well depth-theoretical pressure function relationship; according to the measurement point well depth-theoretical pressure function relationship, drawing a measurement point well depth-theoretical pressure correspondence curve in the measurement point well depth-pressure coordinate system, and obtaining a reconstructed full wellbore pressure field. The present invention can analyze the safety of drilling and completion projects, help to accurately control the wellbore pressure, protect the integrity of the wellbore, ensure the safety of the project and oil and gas wells, and realize the effective use of the measurement data of the pressure measurement chip tool.

Description

Technical Field

[0001] The present invention relates to the fields of oil drilling and completion and natural gas hydrate drilling and production, and in particular to a pressure field reconstruction method and related devices based on a pressure measurement chip tool, and a method and related devices for determining downhole complexity. Background Art

[0002] Pressure is one of the most important parameters related to the safety of drilling and completion projects. Precise control of wellbore pressure plays an important role in ensuring wellbore stability and avoiding the occurrence of underground complications, especially for the development of natural gas hydrates. Under non-low temperature conditions of 0℃-15℃, natural gas hydrates are very unstable and require very high pressure control conditions. If gas invasion occurs, hydrates may form in the wellbore to block the fluid circulation channel, causing more complicated drilling accidents. Therefore, real-time monitoring of the entire wellbore pressure, establishment of pressure acquisition profiles while drilling, and effective processing of the collected pressure data can allow ground engineering personnel to obtain underground pressure information as early as possible, discover possible underground complex formations, and take preventive measures in a timely manner. Summary of the invention

[0003] The inventors found that the existing measurement while drilling technology can only measure the wellbore pressure information near the drill bit, and cannot reflect the three-dimensional pressure changes of the entire wellbore. There is no relevant progress in the processing of measured data by the pressure measurement chip tool, especially in how to effectively use the measurement data of the tool and use it to analyze the complexity of the wellbore. There is no relevant method developed, and it cannot produce practical application effects. In order to at least partially solve the technical problems existing in the prior art, the inventors have made this invention, and through specific implementation methods, provide a pressure field reconstruction method based on the pressure measurement chip tool.

[0004] In a first aspect, an embodiment of the present invention provides a pressure field reconstruction method based on a pressure measurement chip tool, comprising:

[0005] Calculate the well depth and the circulation time of the fluid in the well corresponding to each pressure measurement point of the pressure measurement chip tool, and determine the corresponding relationship between the well depth and the circulation time of the fluid in the well;

[0006] According to the corresponding relationship between the well depth at the measuring point and the circulation time of the fluid in the well, the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points are calculated to obtain a functional relationship between the well depth at the measuring point and the theoretical pressure;

[0007] According to the measuring point well depth-theoretical pressure functional relationship, a measuring point well depth-theoretical pressure corresponding relationship curve is drawn in the measuring point well depth-pressure coordinate system to obtain a reconstructed full wellbore pressure field.

[0008] In some optional embodiments, before calculating the well depth of the measuring point corresponding to each pressure measuring point of the pressure measuring chip tool, the method includes:

[0009] Measure and record the full wellbore depth.

[0010] In some optional embodiments, the calculation of the well depth and the well fluid circulation time corresponding to each pressure measurement point of the pressure measurement chip tool and determining the corresponding relationship between the well depth and the well fluid circulation time include:

[0011] Calculate the time the fluid has been circulating by the time the pressure chip tool reaches the bottom of the well.

[0012] In some optional embodiments, the step of calculating the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well comprises:

[0013] Obtaining measured wellbore pressure values ​​at different pressure measurement points measured by the pressure measurement chip tool;

[0014] When the measured wellbore pressure value reaches a maximum value, determining that the pressure measurement chip tool has reached the bottom of the well;

[0015] Obtain the time from starting the pump cycle to putting the pressure measuring chip tool into the wellhead, the time from putting the pressure measuring chip tool into the wellhead to the completion of the self-activation of the pressure measuring chip tool, and the time from the completion of the self-activation of the pressure measuring chip tool to the time when the measured wellbore pressure value reaches the maximum value;

[0016] The time from starting the pump circulation to putting the pressure measuring chip tool into the wellhead, the time from putting the pressure measuring chip tool into the wellhead to the time when the pressure measuring chip tool is automatically activated, and the time from the time when the pressure measuring chip tool is automatically activated to the time when the measured wellbore pressure value reaches the maximum value are summed to obtain the time when the fluid has circulated when the pressure measuring chip tool reaches the bottom of the well.

[0017] In some optional embodiments, the step of calculating the wellbore fluid circulation time corresponding to each pressure measurement point of the pressure measurement chip tool includes:

[0018] For the first pressure measurement point, the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well is added to a pressure measurement time interval to obtain the fluid circulation time in the well corresponding to the first pressure measurement point of the pressure measurement chip tool;

[0019] For the Nth pressure measurement point, N is greater than 1, the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well is added to the N pressure measurement time intervals to obtain the fluid circulation time in the well corresponding to the Nth pressure measurement point of the pressure measurement chip tool.

[0020] In some optional embodiments, the step of calculating the well depth of each pressure measurement point corresponding to each pressure measurement point of the pressure measurement chip tool includes:

[0021] For the first pressure measurement point, the speed of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point is calculated, and according to the speed of the pressure measurement chip tool returning from the bottom of the well to the first pressure measurement point and the preset pressure measurement time interval, the return distance of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point is calculated as the return distance corresponding to the first pressure measurement point;

[0022] Subtract the return distance corresponding to the first pressure measurement point from the full wellbore depth to obtain the measurement point depth corresponding to the first pressure measurement point;

[0023] For the Nth pressure measurement point, N is greater than 1, the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point is calculated, and according to the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point and the pressure measurement time interval, the return distance of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point is calculated as the return distance corresponding to the Nth pressure measurement point;

[0024] The upward return distances corresponding to the 1st to Nth pressure measurement points are summed to obtain the cumulative upward return distance of the Nth pressure measurement point; the cumulative upward return distance of the Nth pressure measurement point is subtracted from the full wellbore depth to obtain the measurement point depth corresponding to the Nth pressure measurement point.

[0025] In some optional embodiments, the calculating of the speed of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point includes: calculating the average speed of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point, as the speed of the pressure measurement chip tool from the bottom of the well to different positions of the first pressure measurement point; the calculating of the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point includes: calculating the average speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point, as the speed of the pressure measurement chip tool from different positions of the N-1th pressure measurement point.

[0026] In some optional embodiments, the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points are calculated according to the corresponding relationship between the well depth at the measuring point and the circulation time of the fluid in the well, so as to obtain the functional relationship between the well depth at the measuring point and the theoretical pressure, including:

[0027] Establish theoretical pressure field model;

[0028] According to the well depth at the measuring point and the well fluid circulation time corresponding to the well depth at the measuring point, using the theoretical pressure field model, calculating the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points;

[0029] According to the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points, a functional relationship between the well depth at the measuring point and the theoretical pressure is obtained.

[0030] In some optional embodiments, establishing a theoretical pressure field model includes:

[0031] A temperature calculation model for the drill string is established. The formula for the temperature calculation model for the drill string is:

[0032]

[0033] A temperature calculation model for the annulus is established. The formula for the temperature calculation model for the annulus is:

[0034]

[0035] In the formula of the temperature calculation model in the drill string and the formula of the temperature calculation model in the annulus, π is pi, T a , T p are the fluid temperatures in the annulus and drill string, respectively, c a 、c p are the specific heat of the fluid in the annulus and drill string, h pi 、h po are the convective heat transfer coefficients inside and outside the drill string wall, respectively, dp is the thermal conductivity of the drill string, ρ a , p are the fluid densities in the annulus and drill string, respectively, and q m is the drilling fluid circulation displacement, Q cp is the heat generated by the pressure loss in the drill string, z is the depth of the measuring point, t is the circulation time in the well, Δz is the spatial distance, Δt is the time interval, d pi and d po are the inner and outer diameters of the drill string, respectively, and h f is the convective heat transfer coefficient between the formation and the annular fluid, d w is the borehole diameter, T f is the well wall temperature, Q ca The heat generated by the annular pressure loss;

[0036] A calculation model for the density of fluid in the well is established. The formula for the calculation model for the density of fluid in the well is:

[0037] ρ(P,T)=ρ0exp[ξ P (P-P0)+ξ PP (P-P0) 2 +ξT (T-T0)+ξ TT (T-T0) 2 +ξ PT (P-P0)(T-T0)]

[0038] Where P0 is the ground pressure, T0 is the ground temperature, ρ(P,T) is the fluid density when the pressure is P and the temperature is T, ξ P , PP , T , TT , PT The undetermined coefficients are fitted based on the indoor high temperature and high pressure experimental data;

[0039] A wellbore pressure calculation model is established, and the formula of the wellbore pressure calculation model is:

[0040] P=ρgH+P f +P b

[0041] Where ρ is the fluid density in the well, g is the gravitational acceleration, H is the vertical depth of the measuring point, and H is calculated from the well depth and well inclination angle at the measuring point. f is the circulation friction, P b Wellhead back pressure.

[0042] In a second aspect, an embodiment of the present invention provides a method for determining downhole complexity, including:

[0043] Establish the measured full-wellbore pressure field;

[0044] Obtaining a reconstructed full wellbore pressure field according to the pressure field reconstruction method based on the pressure measurement chip tool as described above;

[0045] comparing the measured full-wellbore pressure field with the reconstructed full-wellbore pressure field;

[0046] Based on the comparison results, determine whether underground complexity occurs.

[0047] In some optional embodiments, establishing the measured full wellbore pressure field includes:

[0048] The wellbore pressure at different pressure measurement points is measured and recorded by a pressure measurement chip tool to obtain the measured wellbore pressure values ​​at the different pressure measurement points; the well depth of the measurement point corresponding to each pressure measurement point is calculated; the correspondence between the well depth of the measurement point and the measured wellbore pressure value is determined to obtain the measurement point well depth-measured pressure function relationship; according to the measurement point well depth-measured pressure function relationship, a measurement point well depth-measured pressure correspondence curve is drawn in the measurement point well depth-pressure coordinate system to obtain the measured full wellbore pressure field.

[0049] In some optional embodiments, comparing the measured full-wellbore pressure field with the reconstructed full-wellbore pressure field comprises:

[0050] The measured full wellbore pressure field and the reconstructed full wellbore pressure field are respectively converted into curves corresponding to equivalent circulating density, and the well depth-equivalent circulating density curves of the measuring points corresponding to the measured full wellbore pressure field and the reconstructed full wellbore pressure field are respectively obtained;

[0051] The measured point depth-equivalent circulating density curves of the measured full-wellbore pressure field and the reconstructed full-wellbore pressure field are plotted on the same coordinate system and compared.

[0052] In a third aspect, an embodiment of the present invention provides a pressure field reconstruction device, which uses the aforementioned pressure field reconstruction method based on the pressure measurement chip tool.

[0053] In a fourth aspect, an embodiment of the present invention provides a device for determining downhole complexity, using the aforementioned method for determining downhole complexity.

[0054] In a fifth aspect, an embodiment of the present invention provides a computer storage medium, comprising: the computer storage medium stores computer executable instructions, and when the computer executable instructions are executed by a processor, they implement the aforementioned pressure field reconstruction method based on a pressure measurement chip tool or the aforementioned method for determining downhole complexity.

[0055] In a sixth aspect, an embodiment of the present invention provides a terminal device, characterized in that it comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the pressure field reconstruction method based on the pressure measurement chip tool or the method for determining downhole complexity is implemented.

[0056] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0057] An embodiment of the present invention provides a pressure field reconstruction method based on a pressure measurement chip tool. By drawing a corresponding relationship curve between the well depth and the theoretical pressure at the measurement point, a reconstructed full-wellbore pressure field is obtained. Based on the reconstructed full-wellbore pressure field, the safety of the drilling and completion project can be analyzed, which helps to accurately control the wellbore pressure, protect the integrity of the wellbore, ensure the safety of the project and the oil and gas wells, and realize the effective use of the measurement data of the pressure measurement chip tool.

[0058] The present invention provides a method for determining downhole complexity. By drawing a measurement point well depth-measured pressure correspondence curve and a measurement point well depth-theoretical pressure correspondence curve, the measured full-wellbore pressure field and the reconstructed full-wellbore pressure field are obtained, and the two pressure fields are compared. The comparison result is used as one of the bases for determining whether downhole complexity occurs. The safety of drilling and completion projects can be analyzed, and the effective use of measurement data of pressure measurement chip tools is realized.

[0059] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0060] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0062] Figure 1 This is a flow chart of a pressure field reconstruction method based on a pressure measurement chip tool in one embodiment of the present invention;

[0063] Figure 2 This is a schematic diagram of the movement process of the pressure measurement chip tool in a well in one embodiment of the present invention;

[0064] Figure 3 is a curve diagram of the full wellbore pressure field reconstructed in one embodiment of the present invention;

[0065] Figure 4 A flowchart of a specific implementation process of a pressure field reconstruction method based on a pressure measurement chip tool in one embodiment of the present invention;

[0066] Figure 5 This is a flow chart of a method for determining downhole complexity in one embodiment of the present invention;

[0067] Figure 6 is a curve diagram of the full wellbore pressure field measured in one embodiment of the present invention;

[0068] Figure 7 A flowchart of a specific implementation process of a method for determining downhole complexity in one embodiment of the present invention;

[0069] Figure 8 This is a comparison diagram between the measured wellbore ECD and the reconstructed wellbore ECD in one embodiment of the present invention. DETAILED DESCRIPTION

[0070] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0071] In order to solve the problems existing in the prior art, the embodiments of the present invention provide a method for reconstructing a pressure field, and a method and device for determining downhole complexity.

[0072] The full wellbore depth mentioned in the following embodiments refers to the measured depth of the well, which is the measured length from the drilling floor to the bottom of the well during logging, and is obtained by actual measurement using a measuring tool.

[0073] The well depth of the measuring point appearing in the following embodiments refers to the length from the corresponding position of each pressure measuring point to the drilling floor, which can be obtained by subtracting the return distance of the pressure measurement chip tool from the bottom of the well to the measuring point from the full wellbore depth.

[0074] Embodiment 1

[0075] Embodiment 1 of the present invention provides a pressure field reconstruction method based on a pressure measurement chip tool, and the process is as follows: Figure 1 As shown, the following steps are included:

[0076] Step S101: Calculate the well depth and the circulation time of the fluid in the well corresponding to each pressure measurement point of the pressure measurement chip tool, and determine the corresponding relationship between the well depth and the circulation time of the fluid in the well;

[0077] At present, the monitoring of downhole pressure mainly adopts the measurement while drilling technology. In recent years, a pressure measurement chip tool has been developed at home and abroad. It is carried into the well by the drilling fluid, returned along the annulus after reaching the bottom of the well, and recovered on the ground. This tool measures and stores the wellbore pressure at fixed time intervals, and can measure the pressure data of the entire wellbore.

[0078] Reference Figure 2 The schematic diagram of the movement process of the pressure measurement chip tool in the well is shown. The pressure measurement chip tool is lowered in the drill pipe and put into the wellhead. After the pressure measurement chip tool is activated by itself, it starts to measure and store the pressure value in the wellbore at fixed time intervals. After reaching the bottom of the well, the pressure measurement chip tool enters the annulus and moves upward. After returning a certain distance, it is discharged from the annulus and recovered by the vibrating screen. Then, the measured wellbore pressure values ​​stored in the pressure measurement chip tool at different times are read.

[0079] At the drilling site, the pressure measurement chip tool will not be put into the wellhead immediately after the pump circulation is turned on. This period of preparation time can be recorded as T0, which is the initial circulation time. Due to the limitation of battery power supply time, the pressure measurement chip tool will be activated after a period of time after being put into the wellhead. The time for the pressure measurement chip tool to be activated after being put into the wellbore is recorded as T s Since the pressure in the wellbore increases with the depth of the measuring point, the pressure data measured by the pressure measuring chip tool is the maximum value when it is at the bottom of the well. Therefore, when the measured pressure data is the maximum value, it is determined that the pressure measuring chip tool has reached the bottom of the well. The time corresponding to the maximum value of the pressure data measured by the pressure measuring chip tool is recorded as T b , then the time that the fluid in the well has circulated when the pressure measurement chip tool reaches the bottom of the well is T, T = T0 + T s +T b .

[0080] After the pressure measuring chip tool reaches the bottom of the well, it enters the annulus and returns along the annulus. The pressure measuring chip tool is mainly affected by gravity, buoyancy, lift and other forces in the process of flowing with the fluid in the well. By establishing the motion equation of the pressure measuring chip tool in the wellbore and solving it, the movement speed of the pressure measuring chip tool can be obtained. The upward movement distance of the pressure measuring chip tool between two pressure measurement points is the movement speed of the chip tool multiplied by the measurement time interval. Subtracting the cumulative movement distance of the chip tool from the full wellbore depth is the corresponding measurement point depth of the pressure measuring chip tool at different pressure measurement points.

[0081] After the pressure measurement chip tool reaches the bottom of the well, it enters the annulus and returns along the annulus. According to the obtained fluid circulation time and pressure measurement time interval when the pressure measurement chip tool reaches the bottom of the well, the corresponding fluid circulation time of the pressure measurement chip tool at different pressure measurement points in the annulus can be obtained. Further, combined with the corresponding measurement point well depth of the pressure measurement chip tool at different pressure measurement points, the corresponding relationship between the measurement point well depth and the fluid circulation time in the well at each pressure measurement point of the pressure measurement chip tool can be obtained.

[0082] For example, in the implementation process of the pressure measurement chip tool, the measurement time interval is set to 5s by the single chip computer program, and the measured depth of the implementation well H (ie, the full wellbore depth) is H'=5745m.

[0083] During the implementation of the chip tool, the initial circulation time T0 of the fluid when it is put into the wellhead is 3h, and the chip self-activation time T is set by the single-chip computer program. s According to the curve obtained by the pressure measurement chip tool, the time T corresponding to the maximum value of the pressure measured data of the pressure measurement chip tool is b =0.7h, then the time T0+T0 is the time the fluid has been circulating when the pressure measurement chip tool reaches the bottom of the well.s +T b It is 3h+1.3h+0.7h=5h.

[0084] At the first pressure measurement point of the pressure measurement chip tool in the annulus, the measured wellbore pressure value is 55MPa, and the average movement speed of the pressure measurement chip tool is The pressure measurement chip tool moves back and forth a distance of The corresponding well depth at the measuring point is H1=H′-s1=5745m-2m=5743m, and the corresponding fluid circulation time in the well is T1=T+Δt×1=T0+T s +T b +Δt×1=3h+1.3h+0.7h+0.0014h=5.0014h;

[0085] At the second pressure measurement point, the measured wellbore pressure is 54.9 MPa, and the average movement speed of the pressure measurement chip tool is The cumulative upward and downward movement distance of the pressure measurement chip tool is The corresponding well depth at the measuring point is H2=H′-s2=5745m-4m=5741m, and the corresponding well fluid circulation time is T2=T+Δt×2=T0+T s +T b +Δt×2=3h+1.3h+0.7h+0.0014h×2=5.0028h;

[0086] At the third pressure measurement point, the measured wellbore pressure is 54.83 MPa, and the average movement speed of the pressure measurement chip tool is The cumulative upward and downward movement distance of the pressure measurement chip tool is The corresponding well depth at the measuring point is H3 = H′-s3 = 5745m-6.5m = 5738.5m, and the corresponding well fluid circulation time is T3 = T + Δt × 3 = T0 + T s +T b +Δt×3=3h+1.3h+0.7h+0.0014h×3=5.0042h;

[0087] Similarly, the well depth and the fluid circulation time in the well corresponding to each pressure measurement point of the pressure measurement chip tool are calculated according to the above method, thereby obtaining the corresponding relationship between the well depth and the fluid circulation time in the well.

[0088] Step S101 utilizes the function of the pressure measurement chip tool to measure and store the wellbore pressure at fixed time intervals, and obtains the corresponding relationship between the well depth at the measuring point and the fluid circulation time in the well, which provides input data for the theoretical pressure field model for the next step of using the theoretical pressure field model to calculate the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points.

[0089] Step S102: Calculate theoretical wellbore pressure values ​​corresponding to well depths at different measuring points based on the corresponding relationship between the well depth at the measuring point and the circulation time of the fluid in the well, and obtain a functional relationship between the well depth at the measuring point and the theoretical pressure;

[0090] Extract the fluid property parameters in the wellbore, including density, viscosity, rheological properties, etc. Extract the physical parameters of the wellbore, including the inner and outer diameters of the drill string, the casing layers, the inner and outer diameters of the casing, etc. Extract the corresponding construction conditions, including the drilling process, the cementing process, etc. Establish a theoretical pressure field model under the corresponding state. According to the corresponding construction conditions, substitute the aforementioned drilling parameters such as the fluid property parameters in the wellbore, the physical parameters of the wellbore, etc. into the corresponding positions in the theoretical pressure field model under the established corresponding state.

[0091] For example, Well H is a horizontal well with the following drilling parameters: measured depth (i.e. full wellbore depth) 5745m, vertical depth 4902m, inclination point 4069m. Drilling fluid density 1.31g / cm 3 , n value (fluidity index) is 0.8, k value (consistency coefficient) is 0.2Pa·s n , thermal conductivity 1.73W / (m·℃), circulation displacement 16L / s. Geothermal gradient 0.024℃ / m, rock thermal conductivity 2.25W / (m·℃), surface casing inner diameter 320.4mm, depth 500m; technical casing 1 inner diameter 220.5mm, depth 3430m; technical casing 2 inner diameter 155.8mm, depth 4624m. Drill pipe inner diameter 108.6mm, outer diameter 127mm. Wellbore size 158.4m.

[0092] The theoretical pressure field model under the corresponding state is established. The theoretical pressure field model can be composed of the temperature calculation model in the drill string, the temperature calculation model in the annulus, the fluid density calculation model in the well and the wellbore pressure calculation model.

[0093] A temperature calculation model for the drill string is established. The formula for the temperature calculation model for the drill string is:

[0094]

[0095] A temperature calculation model for the annulus is established. The formula for the temperature calculation model for the annulus is:

[0096]

[0097] In the formula of the temperature calculation model in the drill string and the formula of the temperature calculation model in the annulus, π is pi, T a , T p are the fluid temperatures in the annulus and drill string, respectively, c a 、c p are the specific heat of the fluid in the annulus and drill string, h pi 、h po are the convective heat transfer coefficients inside and outside the drill string wall, respectively, dp is the thermal conductivity of the drill string, ρ a , p are the fluid densities in the annulus and drill string, respectively, and q m is the drilling fluid circulation displacement, Q cp is the heat generated by the pressure loss in the drill string, z is the depth of the measuring point, t is the circulation time in the well, Δz is the spatial distance, Δt is the time interval, d pi and d po are the inner and outer diameters of the drill string, respectively, and h f is the convective heat transfer coefficient between the formation and the annular fluid, d w is the borehole diameter, T f is the well wall temperature, Q ca The heat generated by the annular pressure loss;

[0098] A calculation model for the density of fluid in the well is established. The formula for the calculation model for the density of fluid in the well is:

[0099] ρ(P,T)=ρ0exp[ξ P (P-P0)+ξ PP (P-P0) 2 +ξ T (T-T0)+ξ TT (T-T0) 2 +ξ PT (P-P0)(T-T0)]

[0100] Where P0 is the ground pressure, T0 is the ground temperature, ρ(P,T) is the fluid density when the pressure is P and the temperature is T, ξ P , PP , T , TT , PT The undetermined coefficients are fitted based on the indoor high temperature and high pressure experimental data;

[0101] A wellbore pressure calculation model is established, and the formula of the wellbore pressure calculation model is:

[0102] P=ρgH+P f +P b

[0103] Where ρ is the fluid density in the well, g is the gravitational acceleration, H is the vertical depth of the measuring point, and H is calculated from the well depth and well inclination angle at the measuring point. f is the circulation friction, P b Wellhead back pressure.

[0104] According to the correspondence between the well depth at the pressure measurement point and the circulation time of the fluid in the well, and based on drilling parameters such as the fluid property parameters in the wellbore, the physical parameters of the wellbore and the theoretical pressure field model under the corresponding working conditions, the well depth at the measurement point and the corresponding theoretical wellbore pressure value under the corresponding wellbore fluid circulation time are calculated. Starting from the bottom of the well, the calculation is performed from bottom to top to obtain the theoretical wellbore pressure value corresponding to the well depth of the measurement point at each pressure measurement point, thereby obtaining the measurement point well depth-theoretical pressure function relationship.

[0105] For example, in Well H, the theoretical wellbore pressure value corresponding to the depth of the measuring point is obtained using the above method:

[0106] When the well depth at the measuring point is 5743m, the theoretical wellbore pressure is 55.71MPa;

[0107] When the well depth at the measuring point is 5741m, the theoretical wellbore pressure is 55.65MPa;

[0108] When the well depth at the measuring point is 5738.5m, the theoretical wellbore pressure is 55.59MPa;

[0109] Similarly, the theoretical wellbore pressure value corresponding to the well depth of each pressure measurement point is obtained.

[0110] According to the calculation results of the theoretical wellbore pressure value corresponding to the well depth of each pressure measurement point, the relationship between the well depth and the theoretical pressure function can be obtained, which is recorded as f'(N), where N is the ordinal number of the pressure measurement point and N is a positive integer. From the bottom of the well to the top, it can be expressed as:

[0111] f′(1)=(5743m,55.71MPa)

[0112] f′(2)=(5741m, 55.65MPa)

[0113] f′(3)=(5738.5m, 55.59MPa)

[0114] Similarly, the expression of the relationship between the measuring point well depth and the theoretical pressure function is obtained for each pressure measuring point.

[0115] Step S102 uses the correspondence between the well depth at the measuring point provided in step S101 and the fluid circulation time in the well to calculate the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points, and obtains the measuring point well depth-theoretical pressure function relationship, which provides a data source for realizing pressure field reconstruction.

[0116] Step S103: According to the measurement point well depth-theoretical pressure function relationship, a measurement point well depth-theoretical pressure corresponding relationship curve is drawn in the measurement point well depth-pressure coordinate system to obtain a reconstructed full wellbore pressure field.

[0117] The relationship between the measured point depth and theoretical pressure function is expressed in the form of a Cartesian coordinate system and a curve. Figure 3 The reconstructed full wellbore pressure field curve shown in the figure has the pressure on the horizontal axis in MPa and the depth of the measuring point in m on the vertical axis. According to the function relationship of f′(N), the coordinate points corresponding to all pressure measuring points are plotted. Then, these coordinate points are connected into a continuous curve in descending order of the depth of the measuring point to obtain the corresponding relationship curve between the depth of the measuring point and the theoretical pressure. Figure 3 It can be seen that as the depth of the measuring point increases, the pressure in the wellbore also increases, and after reaching a certain depth of the measuring point, the trend of the wellbore pressure increase slows down significantly, and the pressure reaches the maximum at the bottom of the well. The corresponding relationship curve between the measuring point depth and the theoretical pressure is the final reconstruction result of the full wellbore pressure field.

[0118] Usually, downhole problems such as overflow, leakage, and drilling obstruction are called downhole complexity. Among them, overflow and leakage are one of the most risky downhole complexities. As long as the treatment measures and methods are correct, the downhole complexity will gradually improve and return to normal. However, if it is not handled properly, the downhole complexity may be further aggravated, causing more serious drilling accidents. Wellbore pressure is one of the important parameters for determining downhole complexity.

[0119] In this embodiment, the measured wellbore pressure value and measurement time interval of the pressure measurement chip tool are used to calculate the theoretical wellbore pressure value at each pressure measurement point. By drawing a corresponding relationship curve between the well depth and the theoretical pressure at the measurement point, a reconstructed full wellbore pressure field is obtained. Based on the reconstructed full wellbore pressure field, the safety of the drilling and completion project can be analyzed, which helps to accurately control the wellbore pressure, protect the integrity of the wellbore, ensure the safety of the project and the oil and gas wells, and realize the effective use of the measurement data of the pressure measurement chip tool.

[0120] Embodiment 2

[0121] Embodiment 2 of the present invention provides a specific implementation process of a pressure field reconstruction method based on a pressure measurement chip tool, and the process is as follows: Figure 4 As shown, the following steps are included:

[0122] Step S201: Collect drilling parameters. This includes measuring and recording the full wellbore depth. The full wellbore depth refers to the depth of the entire wellbore. In addition, drilling parameters such as the fluid property parameters in the wellbore and the physical parameters of the wellbore can also be collected for backup. For example, during the implementation of the pressure measurement chip tool in Well H, the depth of Well H (i.e., the full wellbore depth) was 5745m, the vertical depth was 4902m, and the inclination point was 4069m. The drilling fluid density is 1.31g / cm 3 , n value (fluidity index) is 0.8, k value (consistency coefficient) is 0.2Pa·s n , thermal conductivity 1.73W / (m·℃), circulation displacement 16L / s. Geothermal gradient 0.024℃ / m, rock thermal conductivity 2.25W / (m·℃), surface casing inner diameter 320.4mm, depth 500m; technical casing 1 inner diameter 220.5mm, depth 3430m; technical casing 2 inner diameter 155.8mm, depth 4624m. Drill pipe inner diameter 108.6mm, outer diameter 127mm. Wellbore size 158.4m.

[0123] Step S202: Calculate the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well.

[0124] Obtain the measured wellbore pressure values ​​at different pressure measurement points measured by the pressure measurement chip tool; Reference for the use of the pressure measurement chip tool Figure 2 The schematic diagram of the movement process of the pressure measurement chip tool in the well is shown. The pressure measurement chip tool is lowered in the drill pipe and put into the wellhead. After the pressure measurement chip tool is activated by itself, it starts to measure and store the pressure value in the wellbore at fixed time intervals. After reaching the bottom of the well, the pressure measurement chip tool enters the annulus and moves upward. After returning a certain distance, it is discharged from the annulus and recovered by the vibrating screen. Then, the measured wellbore pressure values ​​stored in the pressure measurement chip tool at different times are read.

[0125] When the measured wellbore pressure value reaches a maximum value, it is determined that the pressure measurement chip tool has reached the bottom of the well.

[0126] Obtain the time from starting the pump cycle to putting the pressure measuring chip tool into the wellhead, the time from putting the pressure measuring chip tool into the wellhead to the completion of the self-activation of the pressure measuring chip tool, and the time from the completion of the self-activation of the pressure measuring chip tool to the time when the measured wellbore pressure value reaches the maximum value;

[0127] The time from starting the pump circulation to putting the pressure measuring chip tool into the wellhead, the time from putting the pressure measuring chip tool into the wellhead to the time when the pressure measuring chip tool is automatically activated, and the time from the time when the pressure measuring chip tool is automatically activated to the time when the measured wellbore pressure value reaches the maximum value are summed to obtain the time when the fluid has circulated when the pressure measuring chip tool reaches the bottom of the well.

[0128] For example, at the drilling site, the pressure measurement chip tool will not be put into the wellhead immediately after the pump circulation is turned on. This period of preparation time can be recorded as T0, which is the initial circulation time. Due to the limitation of battery power supply time, the pressure measurement chip tool will automatically activate after a period of time after being put into the wellhead. The time for the pressure measurement chip tool to automatically activate after being put into the wellbore is recorded as T s Since the pressure in the wellbore increases with the depth of the measuring point, the pressure data measured by the pressure measuring chip tool is the maximum value when it is at the bottom of the well. Therefore, when the measured pressure data is the maximum value, it is determined that the pressure measuring chip tool has reached the bottom of the well. The time corresponding to the maximum value of the pressure data measured by the pressure measuring chip tool is recorded as T b , then the time that the fluid in the well has circulated when the pressure measurement chip tool reaches the bottom of the well is T, T = T0 + T s +T b .

[0129] For example, during the implementation of the pressure measurement chip tool in Well H, the initial circulation time T0 of the fluid when the pressure measurement chip tool is put into the wellhead is 3h, and the single-chip microcomputer program sets the chip self-activation time T s According to the curve obtained by the pressure measurement chip tool, the time T corresponding to the maximum value of the pressure measured data of the pressure measurement chip tool is b If it is 0.7h, then the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well is 3h+1.3h+0.7h=5h.

[0130] Step S203: Calculate the well depth and the well fluid circulation time corresponding to each pressure measurement point of the pressure measurement chip tool, and determine the corresponding relationship between the well depth and the well fluid circulation time.

[0131] After the pressure measuring chip tool reaches the bottom of the well, it enters the annulus and returns along the annulus. According to the obtained fluid circulation time when the pressure measuring chip tool reaches the bottom of the well and the pressure measurement time interval, the corresponding fluid circulation time of the pressure measuring chip tool at different pressure measurement points in the annulus can be obtained.

[0132] Calculate the fluid circulation time in the well corresponding to each pressure measurement point of the pressure measurement chip tool, including:

[0133] For the first pressure measurement point, the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well is added to a pressure measurement time interval to obtain the fluid circulation time in the well corresponding to the first pressure measurement point of the pressure measurement chip tool;

[0134] For the Nth pressure measurement point, N is greater than 1, the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well is added to the N pressure measurement time intervals to obtain the well fluid circulation time corresponding to the pressure measurement chip tool at the Nth pressure measurement point. N is the ordinal number of the pressure measurement point, and N is a positive integer.

[0135] For example, during the implementation of the pressure measurement chip tool in Well H, the single chip computer program sets the measurement time interval to 5 seconds. Step S202 obtains that the fluid has circulated for 3 hours + 1.3 hours + 0.7 hours = 5 hours when the pressure measurement chip tool reaches the bottom of the well.

[0136] At the first pressure measurement point in the annulus return of the pressure measurement chip tool, the corresponding well fluid circulation time is T1 = T + Δt × 1 = T0 + T s +T b +Δt×1=3h+1.3h+0.7h+0.0014h=5.0014h;

[0137] At the second pressure measurement point, the corresponding well fluid circulation time is T2 = T + Δt × 2 = T0 + T s +T b +Δt×2=3h+1.3h+0.7h+0.0014h×2=5.0028h;

[0138] At the third pressure measurement point, the corresponding well fluid circulation time is T3 = T + Δt × 3 = T0 + T s +T b +Δt×3=3h+1.3h+0.7h+0.0014h×3=5.0042h;

[0139] Similarly, the well fluid circulation time corresponding to each pressure measurement point of the pressure measurement chip tool is calculated according to the above method.

[0140] Calculate the well depth of each pressure measurement point corresponding to the pressure measurement chip tool, including:

[0141] For the first pressure measurement point, calculate the speed of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point. The pressure measurement microchip is mainly affected by gravity, buoyancy, lift and other forces in the process of flowing with the fluid in the well, and the force on the chip tool is mainly related to its size, overall density, and drilling fluid density and viscosity. The motion equation of the chip tool is established.

[0142]

[0143] By establishing and solving the motion equation, the velocity of the chip tool can be obtained. Since the time interval between the two pressure measurement points is short, the average velocity can be used. Instead of the velocity distribution at different locations.

[0144] Calculating an average speed of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point as the speed of the pressure measurement chip tool at different positions from the bottom of the well to the first pressure measurement point;

[0145] For example, during the implementation of the pressure measurement chip tool in Well H, at the first pressure measurement point in the annulus, the average speed of the pressure measurement chip tool is Calculated

[0146] Similarly, calculating the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point includes: calculating the average speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point as the speed of the pressure measurement chip tool at different positions of the N-1th pressure measurement point. At the second pressure measurement point, the average speed of the pressure measurement chip tool is Calculated At the third pressure measurement point, the average speed of the pressure measurement chip tool is Calculated

[0147] According to the speed at which the pressure measuring chip tool returns from the bottom of the well to the first pressure measuring point and the preset pressure measuring time interval, the return distance of the pressure measuring chip tool from the bottom of the well to the first pressure measuring point is calculated as the return distance corresponding to the first pressure measuring point;

[0148] Subtract the return distance corresponding to the first pressure measurement point from the full wellbore depth to obtain the measurement point depth corresponding to the first pressure measurement point;

[0149] For example, during the implementation of the pressure measurement chip tool in Well H, the measurement time interval was set to 5s. When the pressure measurement chip tool returned to the first pressure measurement point in the annulus, the average movement speed of the pressure measurement chip tool was The pressure measurement chip tool moves back and forth a distance of The corresponding well depth of the measuring point is H1 = H′-s1 = 5745m-2m = 5743m;

[0150] For the Nth pressure measurement point, N is greater than 1, the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point is calculated, and according to the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point and the pressure measurement time interval, the return distance of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point is calculated as the return distance corresponding to the Nth pressure measurement point;

[0151] The upward return distances corresponding to the 1st to Nth pressure measurement points are summed to obtain the cumulative upward return distance of the Nth pressure measurement point; the cumulative upward return distance of the Nth pressure measurement point is subtracted from the full wellbore depth to obtain the measurement point depth corresponding to the Nth pressure measurement point.

[0152] For example, during the implementation of the pressure measurement chip tool in Well H, the measurement time interval was set to 5s. At the second pressure measurement point, the average movement speed of the pressure measurement chip tool was The cumulative upward and downward movement distance of the pressure measurement chip tool is The corresponding well depth at the measuring point is H2 = H′-s2 = 5745m-4m = 5741m;

[0153] At the third pressure measurement point, the average speed of the pressure measurement chip tool is The cumulative upward and downward movement distance of the pressure measurement chip tool is The corresponding well depth at the measuring point is H3 = H′-s3 = 5745m-6.5m = 5738.5m;

[0154] Similarly, the well depths of the measuring points corresponding to the pressure measuring points of the pressure measuring chip tool are calculated according to the above method.

[0155] According to the calculated measuring point well depth and well fluid circulation time corresponding to each pressure measuring point of the pressure measurement chip tool, the corresponding relationship between the measuring point well depth and the well fluid circulation time is determined.

[0156] For example, in Well H, the well depth at the measuring point is 5743m, and the corresponding fluid circulation time in the well is 5.0014h; the well depth at the measuring point is 5741m, and the corresponding fluid circulation time in the well is 5.0028h; the well depth at the measuring point is 5738.5m, and the corresponding fluid circulation time in the well is 5.0042h.

[0157] Step S204: Calculate the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points according to the corresponding relationship between the well depth at the measuring point and the circulation time of the fluid in the well, and obtain a functional relationship between the well depth at the measuring point and the theoretical pressure;

[0158] Establish a theoretical pressure field model. The theoretical pressure field model can be composed of a temperature calculation model in the drill string, a temperature calculation model in the annulus, a fluid density calculation model in the well, and a wellbore pressure calculation model.

[0159] A temperature calculation model for the drill string is established. The formula for the temperature calculation model for the drill string is:

[0160]

[0161] A temperature calculation model for the annulus is established. The formula for the temperature calculation model for the annulus is:

[0162]

[0163] In the formula of the temperature calculation model in the drill string and the formula of the temperature calculation model in the annulus, π is pi, T a , T p are the fluid temperatures in the annulus and drill string, respectively, c a 、c p are the specific heat of the fluid in the annulus and drill string, h pi 、h po are the convective heat transfer coefficients inside and outside the drill string wall, respectively, dp is the thermal conductivity of the drill string, ρ a , p are the fluid densities in the annulus and drill string, respectively, and q m is the drilling fluid circulation displacement, Q cp is the heat generated by the pressure loss in the drill string, z is the depth of the measuring point, t is the circulation time in the well, Δz is the spatial distance, Δt is the time interval, d pi and d po are the inner and outer diameters of the drill string, respectively, and h f is the convective heat transfer coefficient between the formation and the annular fluid, d w is the borehole diameter, T f is the well wall temperature, Q ca The heat generated by the annular pressure loss;

[0164] A calculation model for the density of fluid in the well is established. The formula for the calculation model for the density of fluid in the well is:

[0165] ρ(P,T)=ρ0exp[ξ P (P-P0)+ξ PP (P-P0) 2 +ξ T (T-T0)+ξ TT (T-T0) 2 +ξ PT (P-P0)(T-T0)]

[0166] Where P0 is the ground pressure, T0 is the ground temperature, ρ(P,T) is the fluid density when the pressure is P and the temperature is T, ξ P , PP , T , TT , PT The undetermined coefficients are fitted based on the indoor high temperature and high pressure experimental data;

[0167] A wellbore pressure calculation model is established, and the formula of the wellbore pressure calculation model is:

[0168] P=ρgH+P f +P b

[0169] Where ρ is the fluid density in the well, g is the gravitational acceleration, H is the vertical depth of the measuring point, and H is calculated from the well depth and well inclination angle at the measuring point. f is the circulation friction, P b Wellhead back pressure.

[0170] According to the well depth at the measuring point and the well fluid circulation time corresponding to the well depth at the measuring point, using the theoretical pressure field model, calculating the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points;

[0171] Extract the fluid property parameters in the wellbore, including density, viscosity, rheological properties, etc. Extract the physical parameters of the wellbore, including the inner and outer diameters of the drill string, the casing layers, the inner and outer diameters of the casing, etc. Extract the corresponding construction conditions, including the drilling process, the cementing process, etc. Establish a theoretical pressure field model under the corresponding state. According to the corresponding construction conditions, substitute the aforementioned drilling parameters such as the fluid property parameters in the wellbore, the physical parameters of the wellbore, etc. into the corresponding positions in the theoretical pressure field model under the established corresponding state.

[0172] According to the correspondence between the well depth at the pressure measurement point and the circulation time of the fluid in the well, and based on drilling parameters such as the fluid property parameters in the wellbore, the physical parameters of the wellbore and the theoretical pressure field model under the corresponding working conditions, the well depth at the measurement point and the corresponding theoretical wellbore pressure value under the corresponding wellbore fluid circulation time are calculated. Starting from the bottom of the well, the calculation is performed from bottom to top to obtain the theoretical wellbore pressure value corresponding to the well depth of the measurement point at each pressure measurement point, thereby obtaining the measurement point well depth-theoretical pressure function relationship.

[0173] For example, in Well H, the theoretical wellbore pressure value corresponding to the depth of the measuring point is obtained using the above method:

[0174] When the well depth at the measuring point is 5743m, the theoretical wellbore pressure is 55.71MPa;

[0175] When the well depth at the measuring point is 5741m, the theoretical wellbore pressure is 55.65MPa;

[0176] When the well depth at the measuring point is 5738.5m, the theoretical wellbore pressure is 55.59MPa;

[0177] Similarly, the theoretical wellbore pressure value corresponding to the well depth of each pressure measurement point is obtained.

[0178] According to the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points, a functional relationship between the well depth at the measuring point and the theoretical pressure is obtained.

[0179] According to the calculation results of the theoretical wellbore pressure value corresponding to the well depth of each pressure measurement point, the relationship between the well depth and the theoretical pressure function can be obtained, which is recorded as f'(N), where N is the ordinal number of the pressure measurement point and N is a positive integer. From the bottom of the well to the top, it can be expressed as:

[0180] f′(1)=(5743m,55.71MPa)

[0181] f′(2)=(5741m, 55.65MPa)

[0182] f′(3)=(5738.5m, 55.59MPa)

[0183] Similarly, the expression of the relationship between the measuring point well depth and the theoretical pressure function is obtained for each pressure measuring point.

[0184] Step S205: According to the measuring point well depth-theoretical pressure function relationship, a measuring point well depth-theoretical pressure corresponding relationship curve is drawn in the measuring point well depth-pressure coordinate system to obtain a reconstructed full wellbore pressure field.

[0185] The relationship between the measured point depth and theoretical pressure function is expressed in the form of a Cartesian coordinate system and a curve. Figure 3 The reconstructed full wellbore pressure field curve shown in the figure has the pressure on the horizontal axis in MPa and the depth of the measuring point in m on the vertical axis. According to the function relationship of f′(N), the coordinate points corresponding to all pressure measuring points are plotted. Then, these coordinate points are connected into a continuous curve in descending order of the depth of the measuring point to obtain the corresponding relationship curve between the depth of the measuring point and the theoretical pressure. Figure 3 It can be seen that as the depth of the measuring point increases, the pressure in the wellbore also increases, and after reaching a certain depth of the measuring point, the trend of the wellbore pressure increase slows down significantly, and the pressure reaches the maximum at the bottom of the well. The corresponding relationship curve between the measuring point depth and the theoretical pressure is the reconstructed full wellbore pressure field.

[0186] Usually, downhole problems such as overflow, leakage, and drilling obstruction are called downhole complexity. Among them, overflow and leakage are one of the most risky downhole complexities. As long as the treatment measures and methods are correct, the downhole complexity will gradually improve and return to normal. However, if it is not handled properly, the downhole complexity may be further aggravated, causing more serious drilling accidents. Wellbore pressure is one of the important parameters for determining downhole complexity.

[0187] In this embodiment, the measured wellbore pressure value and measurement time interval of the pressure measurement chip tool are used to calculate the theoretical wellbore pressure value at each pressure measurement point. By drawing a corresponding relationship curve between the well depth and the theoretical pressure at the measurement point, a reconstructed full wellbore pressure field is obtained. Based on the reconstructed full wellbore pressure field, the safety of the drilling and completion project can be analyzed, which helps to accurately control the wellbore pressure, protect the integrity of the wellbore, ensure the safety of the project and the oil and gas wells, and realize the effective use of the measurement data of the pressure measurement chip tool.

[0188] Embodiment 3

[0189] Embodiment 3 of the present invention provides a method for determining the complexity of a well, and the process is as follows: Figure 5 As shown, the following steps are included:

[0190] Step S301: Establishing the measured full-wellbore pressure field.

[0191] The wellbore pressure at different pressure measurement points is measured and recorded using a pressure measurement chip tool to obtain actual wellbore pressure values ​​at the different pressure measurement points; for example, at the first pressure measurement point in the annulus where the pressure measurement chip tool is returning, the actual wellbore pressure value is 55 MPa, at the second pressure measurement point, the actual wellbore pressure value is 54.9 MPa, and at the third pressure measurement point, the actual wellbore pressure value is 54.83 MPa. Similarly, the actual wellbore pressure values ​​at each pressure measurement point of the pressure measurement chip tool are obtained according to the above method.

[0192] Calculate the well depth of the measuring point corresponding to each pressure measuring point; the method of calculating the well depth of the measuring point corresponding to each pressure measuring point has been introduced in detail in the first and second embodiments of the present invention.

[0193] Determine the corresponding relationship between the well depth of the measuring point and the measured wellbore pressure value, and obtain the functional relationship between the well depth and the measured pressure at the measuring point; for example, in Well H, when the well depth of the measuring point is 5743m, the measured wellbore pressure value is 55MPa, when the well depth of the measuring point is 5741m, the measured wellbore pressure value is 54.9MPa, and when the well depth of the measuring point is 5738.5m, the measured wellbore pressure value is 54.83MPa, until the well depths of the measuring points and the corresponding measured wellbore pressure values ​​of all pressure measurement points are obtained.

[0194] According to the calculation results of the measured wellbore pressure value corresponding to the well depth of each pressure measurement point, the function relationship between the well depth and the measured pressure can be obtained, which is recorded as f(N), where N is the ordinal number of the pressure measurement point and N is a positive integer. From the bottom of the well to the top, it can be expressed as:

[0195] f(1)=(5743m,55MPa)

[0196] f(2) = (5741 m, 54.9 MPa)

[0197] f(3)=(5738.5m, 54.83MPa)

[0198] Similarly, the expression of the functional relationship between the measuring point well depth and the measured pressure at each pressure measuring point is obtained.

[0199] According to the measuring point well depth-measured pressure functional relationship, a measuring point well depth-measured pressure corresponding relationship curve is drawn in the measuring point well depth-pressure coordinate system to obtain the measured full wellbore pressure field.

[0200] The relationship between the measured point depth and measured pressure function is expressed in the form of a Cartesian coordinate system and a curve. Figure 6 The measured full wellbore pressure field curve shown in the figure has the pressure on the horizontal axis in MPa and the depth of the measuring point in m on the vertical axis. According to the function relationship of f(N), the coordinate points corresponding to all pressure measuring points are plotted. Then, these coordinate points are connected into a continuous curve in descending order of the depth of the measuring point to obtain the corresponding relationship curve between the depth of the measuring point and the theoretical pressure. Figure 6 It can be seen that as the depth of the measuring point increases, the pressure in the wellbore also increases overall. After reaching a certain depth of the measuring point, the measured wellbore pressure value does not increase significantly, and the measured wellbore pressure value reaches the maximum at the bottom of the well. The corresponding relationship curve between the measuring point depth and the measured pressure is the measured full wellbore pressure field.

[0201] Step S302: Establish a reconstructed full-wellbore pressure field; the specific method has been introduced in Embodiment 1 and Embodiment 2.

[0202] Step S303: Compare the measured full-wellbore pressure field with the reconstructed full-wellbore pressure field, and determine whether downhole complexity occurs based on the comparison result.

[0203] The corresponding relationship curve between the measuring point well depth and the measured pressure and the corresponding relationship curve between the measuring point well depth and the theoretical pressure are plotted on the same coordinate system and compared to obtain a comparison result.

[0204] According to the comparison results of the well depth-measured pressure correspondence curve at the measuring point and the well depth-theoretical pressure correspondence curve at the measuring point, it is determined whether the well has downhole complexity. For example, in the implementation of Well H, according to the comparison of the well depth-measured pressure correspondence curve at the measuring point and the well depth-theoretical pressure correspondence curve at the measuring point, it is determined that the well has no downhole complexity during the circulation drilling process.

[0205] Usually, downhole problems such as overflow, leakage, and drilling obstruction are called downhole complexity. Among them, overflow and leakage are one of the most risky downhole complexities. As long as the treatment measures and methods are correct, the downhole complexity will gradually improve and return to normal. However, if it is not handled properly, the downhole complexity may be further aggravated, causing more serious drilling accidents. Wellbore pressure is one of the important parameters for determining downhole complexity.

[0206] In this implementation, the measured wellbore pressure values ​​and measurement time intervals of the pressure measurement chip tool are used to obtain the measurement point depth of each pressure measurement point and the corresponding measured wellbore pressure value and theoretical wellbore pressure value. By plotting the measurement point well depth-measured pressure correspondence curve and the measurement point well depth-theoretical pressure correspondence curve, the measured full-wellbore pressure field and the reconstructed full-wellbore pressure field are obtained. The two pressure fields are compared, and the comparison result is used as one of the bases for determining whether underground complexity occurs. The safety of the drilling and completion project can be analyzed, thereby realizing the effective use of the measurement data of the pressure measurement chip tool.

[0207] Embodiment 4

[0208] Embodiment 4 of the present invention provides a specific implementation process of a method for determining the complexity of a well, and the process is as follows: Figure 7 As shown, the following steps are included:

[0209] Step S401: establishing a measured full wellbore pressure field;

[0210] The wellbore pressure at different pressure measurement points is measured and recorded using a pressure measurement chip tool to obtain actual wellbore pressure values ​​at the different pressure measurement points; for example, at the first pressure measurement point in the annulus where the pressure measurement chip tool is returning, the actual wellbore pressure value is 55 MPa, at the second pressure measurement point, the actual wellbore pressure value is 54.9 MPa, and at the third pressure measurement point, the actual wellbore pressure value is 54.83 MPa. Similarly, the actual wellbore pressure values ​​at each pressure measurement point of the pressure measurement chip tool are obtained according to the above method.

[0211] Calculate the well depth of the measuring point corresponding to each pressure measuring point; the method of calculating the well depth of the measuring point corresponding to each pressure measuring point has been introduced in detail in the first and second embodiments of the present invention.

[0212] Determine the corresponding relationship between the well depth of the measuring point and the measured wellbore pressure value, and obtain the functional relationship between the well depth and the measured pressure at the measuring point; for example, in Well H, when the well depth of the measuring point is 5743m, the measured wellbore pressure value is 55MPa, when the well depth of the measuring point is 5741m, the measured wellbore pressure value is 54.9MPa, and when the well depth of the measuring point is 5738.5m, the measured wellbore pressure value is 54.83MPa, until the well depths of the measuring points and the corresponding measured wellbore pressure values ​​of all pressure measurement points are obtained.

[0213] According to the calculation results of the measured wellbore pressure value corresponding to the well depth of each pressure measurement point, the function relationship between the well depth and the measured pressure can be obtained, which is recorded as f(N), where N is the ordinal number of the pressure measurement point and N is a positive integer. From the bottom of the well to the top, it can be expressed as:

[0214] f(1)=(5743m,55MPa)

[0215] f(2) = (5741 m, 54.9 MPa)

[0216] f(3)=(5738.5m, 54.83MPa)

[0217] Similarly, the expression of the functional relationship between the measuring point well depth and the measured pressure at each pressure measuring point is obtained.

[0218] According to the measuring point well depth-measured pressure functional relationship, a measuring point well depth-measured pressure corresponding relationship curve is drawn in the measuring point well depth-pressure coordinate system to obtain the measured full wellbore pressure field.

[0219] The relationship between the measured point depth and measured pressure function is expressed in the form of a Cartesian coordinate system and a curve. Figure 6 The measured full wellbore pressure field curve shown in the figure has the pressure on the horizontal axis in MPa and the depth of the measuring point in m on the vertical axis. According to the function relationship of f(N), the coordinate points corresponding to all pressure measuring points are plotted. Then, these coordinate points are connected into a continuous curve in descending order of the depth of the measuring point to obtain the corresponding relationship curve between the depth of the measuring point and the theoretical pressure. Figure 6 It can be seen that as the depth of the measuring point increases, the pressure in the wellbore also increases overall. After reaching a certain depth of the measuring point, the measured wellbore pressure value does not increase significantly, and the measured wellbore pressure value reaches the maximum at the bottom of the well. The corresponding relationship curve between the measuring point depth and the measured pressure is the measured full wellbore pressure field.

[0220] Step S402: Establish a reconstructed full wellbore pressure field. The specific method has been introduced in the first and second embodiments.

[0221] Step S403: Convert the pressure into equivalent circulating density. In some optional embodiments, since equivalent circulating density, namely ECD (Equivalent circulating density), is often used as a representation of wellbore pressure in field engineering, the pressure is converted into equivalent circulating density.

[0222] The measured full wellbore pressure field and the reconstructed full wellbore pressure field are respectively converted into curves corresponding to equivalent circulating density, and the well depth-equivalent circulating density curves of the measuring points corresponding to the measured full wellbore pressure field and the reconstructed full wellbore pressure field are respectively obtained;

[0223] Step S404: Compare the measured full-wellbore pressure field with the reconstructed full-wellbore pressure field, and determine whether downhole complexity occurs based on the comparison result.

[0224] The measured full wellbore pressure field and the measured point depth-equivalent circulating density curve of the reconstructed full wellbore pressure field are plotted on the same coordinate system and compared. According to the comparison result, it is determined whether the downhole is complicated. For example, in the implementation of H well, refer to Figure 8 The comparison diagram of measured wellbore ECD and reconstructed wellbore ECD is shown. In the figure, the smoother curve on the left is the equivalent circulating density curve transformed from the corresponding relationship curve of the measuring point well depth-theoretical pressure, and the jagged curve on the left is the equivalent circulating density curve transformed from the corresponding relationship curve of the measuring point well depth-measured pressure. According to the comparison diagram of measured wellbore ECD and reconstructed wellbore ECD, it is determined that the well did not have downhole complications during the circulation drilling process.

[0225] Usually, downhole problems such as overflow, leakage, and drilling obstruction are called downhole complexity. Among them, overflow and leakage are one of the most risky downhole complexities. As long as the treatment measures and methods are correct, the downhole complexity will gradually improve and return to normal. However, if it is not handled properly, the downhole complexity may be further aggravated, causing more serious drilling accidents. Wellbore pressure is one of the important parameters for determining downhole complexity.

[0226] In this implementation, the measured wellbore pressure values ​​and measurement time intervals of the pressure measurement chip tool are used to obtain the measurement point depth of each pressure measurement point and the corresponding measured wellbore pressure value and theoretical wellbore pressure value. By plotting the measurement point well depth-measured pressure correspondence curve and the measurement point well depth-theoretical pressure correspondence curve, the measured full-wellbore pressure field and the reconstructed full-wellbore pressure field are obtained. The two pressure fields are compared, and the comparison result is used as one of the bases for determining whether underground complexity occurs. The safety of the drilling and completion project can be analyzed, thereby realizing the effective use of the measurement data of the pressure measurement chip tool.

[0227] Based on the same inventive concept, an embodiment of the present invention further provides a pressure field reconstruction device, which uses the aforementioned pressure field reconstruction method based on the pressure measurement chip tool.

[0228] Based on the same inventive concept, an embodiment of the present invention further provides a device for determining downhole complexity, which uses the aforementioned method for determining downhole complexity.

[0229] Based on the same inventive concept, an embodiment of the present invention also provides a computer storage medium, in which computer executable instructions are stored. When the computer executable instructions are executed by a processor, the pressure field reconstruction method based on the pressure measurement chip tool or the method for determining downhole complexity can be implemented.

[0230] Based on the same inventive concept, an embodiment of the present invention also provides a terminal device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the aforementioned pressure field reconstruction method based on the pressure measurement chip tool or the aforementioned method for determining downhole complexity is implemented.

[0231] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0232] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0233] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

Claims

1. A pressure field reconstruction method based on a pressure measurement chip tool, characterized in that: include: Calculate the well depth and the circulation time of the fluid in the well corresponding to each pressure measurement point of the pressure measurement chip tool, and determine the corresponding relationship between the well depth and the circulation time of the fluid in the well; According to the corresponding relationship between the well depth at the measuring point and the circulation time of the fluid in the well, the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points are calculated to obtain a functional relationship between the well depth at the measuring point and the theoretical pressure; According to the measuring point well depth-theoretical pressure function relationship, a measuring point well depth-theoretical pressure corresponding relationship curve is drawn in the measuring point well depth-pressure coordinate system to obtain a reconstructed full wellbore pressure field; According to the corresponding relationship between the well depth at the measuring point and the circulation time of the fluid in the well, the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points are calculated to obtain the functional relationship between the well depth at the measuring point and the theoretical pressure, including: Establish theoretical pressure field model; According to the well depth at the measuring point and the well fluid circulation time corresponding to the well depth at the measuring point, using the theoretical pressure field model, calculating the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points; According to the theoretical wellbore pressure values ​​corresponding to the well depths at different measuring points, a functional relationship between the well depth at the measuring point and the theoretical pressure is obtained; The establishing of the theoretical pressure field model comprises: A temperature calculation model for the drill string is established. The formula for the temperature calculation model for the drill string is: A temperature calculation model for the annulus is established. The formula of the temperature calculation model for the annulus is: In the formula of the temperature calculation model in the drill string and the formula of the temperature calculation model in the annulus, π is pi, T a 、T p are the fluid temperatures in the annulus and drill string, respectively, c a 、c p are the specific heat of the fluid in the annulus and drill string, h pi 、h po are the convective heat transfer coefficients inside and outside the drill string wall, respectively, dp is the thermal conductivity of the drill string, ρ a , p are the fluid densities in the annulus and drill string, respectively, and q m is the drilling fluid circulation displacement, Q cp is the heat generated by the pressure loss in the drill string, z is the depth of the measuring point, t is the circulation time in the well, Δz is the spatial distance, Δt is the time interval, d pi and d po are the inner and outer diameters of the drill string, respectively, and h f is the convective heat transfer coefficient between the formation and the annular fluid, d w is the borehole diameter, T f is the well wall temperature, Q ca The heat generated by the annular pressure loss; A calculation model for the density of fluid in the well is established. The formula for the calculation model for the density of fluid in the well is: ρ(P,T)=ρ0exp[ξ P (P-P0)+ξ PP (P-P0) 2 +ξ T (T-T0)+ξ TT (T-T0) 2 +ξ PT (P-P0)(T-T0)] Where P0 is the ground pressure, T0 is the ground temperature, ρ(P,T) is the fluid density when the pressure is P and the temperature is T, ξ P , PP , T , TT , PT The undetermined coefficients are fitted based on the indoor high temperature and high pressure experimental data; A wellbore pressure calculation model is established, and the formula of the wellbore pressure calculation model is: P=ρgH+P f +P b Where ρ is the fluid density in the well, g is the gravitational acceleration, H is the vertical depth of the measuring point, and H is calculated from the well depth and well inclination angle at the measuring point. f is the circulation friction, P b Wellhead back pressure.

2. The method according to claim 1, characterized in that Before calculating the well depth of the measuring point corresponding to each pressure measuring point of the pressure measuring chip tool, the method includes: Measure and record the full wellbore depth.

3. The method according to claim 1, characterized in that Before calculating the well depth and the well fluid circulation time corresponding to each pressure measurement point of the pressure measurement chip tool and determining the corresponding relationship between the well depth and the well fluid circulation time, the method includes: Calculate the time the fluid has been circulating by the time the pressure chip tool reaches the bottom of the well.

4. The method according to claim 3, characterized in that The method of calculating the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well comprises: Obtaining measured wellbore pressure values ​​at different pressure measurement points measured by the pressure measurement chip tool; When the measured wellbore pressure value reaches a maximum value, determining that the pressure measurement chip tool has reached the bottom of the well; Obtain the time from starting the pump cycle to putting the pressure measuring chip tool into the wellhead, the time from putting the pressure measuring chip tool into the wellhead to the completion of the self-activation of the pressure measuring chip tool, and the time from the completion of the self-activation of the pressure measuring chip tool to the time when the measured wellbore pressure value reaches the maximum value; The time from starting the pump circulation to putting the pressure measuring chip tool into the wellhead, the time from putting the pressure measuring chip tool into the wellhead to the time when the pressure measuring chip tool is automatically activated, and the time from the time when the pressure measuring chip tool is automatically activated to the time when the measured wellbore pressure value reaches the maximum value are summed to obtain the time when the fluid has circulated when the pressure measuring chip tool reaches the bottom of the well.

5. The method according to claim 3, characterized in that The method of calculating the well fluid circulation time corresponding to each pressure measurement point of the pressure measurement chip tool comprises: For the first pressure measurement point, the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well is added to a pressure measurement time interval to obtain the fluid circulation time in the well corresponding to the first pressure measurement point of the pressure measurement chip tool; For the Nth pressure measurement point, N is greater than 1, the time that the fluid has circulated when the pressure measurement chip tool reaches the bottom of the well is added to the N pressure measurement time intervals to obtain the fluid circulation time in the well corresponding to the Nth pressure measurement point of the pressure measurement chip tool.

6. The method according to claim 1, characterized in that The method of calculating the well depth of each pressure measuring point corresponding to each pressure measuring point of the pressure measuring chip tool comprises: For the first pressure measurement point, the speed of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point is calculated, and according to the speed of the pressure measurement chip tool returning from the bottom of the well to the first pressure measurement point and the preset pressure measurement time interval, the return distance of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point is calculated as the return distance corresponding to the first pressure measurement point; Subtract the return distance corresponding to the first pressure measurement point from the full wellbore depth to obtain the measurement point depth corresponding to the first pressure measurement point; For the Nth pressure measurement point, N is greater than 1, the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point is calculated, and according to the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point and the pressure measurement time interval, the return distance of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point is calculated as the return distance corresponding to the Nth pressure measurement point; The upward return distances corresponding to the 1st to Nth pressure measurement points are summed to obtain the cumulative upward return distance of the Nth pressure measurement point; the cumulative upward return distance of the Nth pressure measurement point is subtracted from the full wellbore depth to obtain the measurement point depth corresponding to the Nth pressure measurement point.

7. The method according to claim 6, characterized in that The method of calculating the speed of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point comprises: Calculating an average speed of the pressure measurement chip tool from the bottom of the well to the first pressure measurement point as the speed of the pressure measurement chip tool at different positions from the bottom of the well to the first pressure measurement point; The calculating the speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point includes: The average speed of the pressure measurement chip tool from the N-1th pressure measurement point to the Nth pressure measurement point is calculated as the speed of the pressure measurement chip tool at different positions from the N-1th pressure measurement point.

8. A method for determining downhole complexity, characterized in that: include: Establish the measured full-wellbore pressure field; Establishing a reconstructed full wellbore pressure field according to the pressure field reconstruction method based on the pressure measurement chip tool as described in any one of claims 1 to 7; The measured full-wellbore pressure field is compared with the reconstructed full-wellbore pressure field, and whether downhole complexity occurs is determined based on the comparison result.

9. The method according to claim 8, characterized in that The step of establishing the measured full wellbore pressure field comprises: Using a pressure measurement chip tool to measure and record the wellbore pressure at different pressure measurement points, and obtain the measured wellbore pressure values ​​at the different pressure measurement points; Calculate the well depth of each pressure measurement point corresponding to each pressure measurement point; Determine the corresponding relationship between the well depth at the measuring point and the measured wellbore pressure value, and obtain a functional relationship between the well depth at the measuring point and the measured pressure; According to the measuring point well depth-measured pressure functional relationship, a measuring point well depth-measured pressure corresponding relationship curve is drawn in the measuring point well depth-pressure coordinate system to obtain the measured full wellbore pressure field.

10. The method according to claim 9, characterized in that Comparing the measured full-wellbore pressure field with the reconstructed full-wellbore pressure field, and determining whether downhole complexity occurs according to the comparison result, including: The measured full wellbore pressure field and the reconstructed full wellbore pressure field are respectively converted into curves corresponding to equivalent circulating density, and the well depth-equivalent circulating density curves of the measuring points corresponding to the measured full wellbore pressure field and the reconstructed full wellbore pressure field are respectively obtained; The measured full-wellbore pressure field and the measured point depth-equivalent circulating density curve of the reconstructed full-wellbore pressure field are plotted on the same coordinate system and compared. Based on the comparison result, it is determined whether downhole complexity occurs.

11. A pressure field reconstruction device, characterized in that: A pressure field reconstruction method based on a pressure measurement chip tool as described in any one of claims 1 to 7 is used.

12. A device for determining downhole complexity, characterized in that: A method for determining downhole complexity as described in any one of claims 8 to 10 is used.

13. A computer storage medium, characterized in that: The computer storage medium stores computer executable instructions, which, when executed by a processor, implement a pressure field reconstruction method based on a pressure measurement chip tool as described in any one of claims 1-7 or a method for determining downhole complexity as described in any one of claims 8-10.

14. A terminal device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for reconstructing a pressure field based on a pressure measurement chip tool as described in any one of claims 1 to 7 or a method for determining downhole complexity as described in any one of claims 8 to 10 is implemented.

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