Method for determining oil column height of carbonate rock fault karst reservoir and related device

Abstract

The invention discloses an oil column height determination method for a carbonate fault-karst reservoir and a related device, and the method comprises the steps: collecting temperature test data and geological data of a carbonate fault-control reservoir oil well, and obtaining static temperature test data at the initial stage of commissioning and flow temperature test data at the preset commissioning date; establishing a fault-karst oil reservoir shaft-oil reservoir coupling thermodynamic physical model; establishing a wellbore temperature distribution model by utilizing energy conservation, and calculating the bottom hole temperature through the wellhead temperature; establishing a one-dimensional vertical thermodynamic model of the oil reservoir, and performing iterative calculation to obtain the height from the bottom of the well to the bottom of the oil reservoir; and adding the calculated height to the height of the drilling development layer series of the drilling well to obtain the oil column height of the carbonate rock fault karst reservoir. The method for calculating the oil column height of the carbonate rock fault karst reservoir is determined on the basis of the thermodynamic model of shaft-reservoir coupling, the oil column height of the fault karst reservoir can be calculated by directly utilizing wellhead temperature data, and the problem that a conventional static description means is large in calculation error is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development and reservoir engineering, and in particular relates to a method for determining the oil column height of a carbonate fault-karst reservoir and a related device. Background Art

[0002] In recent years, the proportion of carbonate oil and gas reservoirs in my country's oil and gas resources has continued to increase, and the development potential has gradually increased. It is a key area for future oil and gas reserve increase. How to reasonably and effectively develop this type of oil reservoir has become a difficult problem that needs to be urgently solved in the oil field.

[0003] Major oil and gas breakthroughs have been made in the ultra-deep carbonate rock field below 7,000 meters. The carbonate fault-karst oil reservoirs in the Tarim Basin have a large number of strike-slip faults developed, which have been transformed by multiple periods of karstification to form fracture-cavity reservoirs. The reservoir types are mainly large caves, supplemented by fractures and holes. They are characterized by overall oil content and uneven enrichment along the fault zone. The discovery of this type of oil and gas reservoirs has demonstrated a new ultra-deep oil and gas enrichment accumulation model.

[0004] The oil column height refers to the vertical distance from the oil-water interface to the top of the reservoir. The size of the oil column height is a crucial parameter for determining the size of the reservoir, reservoir research, and production management. For layered oil and gas reservoirs, the oil column height parameters can be calculated by determining the structural highs, oil-water interface, and closure overflow points; but for carbonate fault-karst reservoirs, the internal heterogeneity is extremely strong, and many large-scale karst caves are prone to emptying and leakage, which makes it impossible to drill through the bottom of the reservoir to obtain the true oil column height. At present, the industry usually uses static seismic carving methods to determine the oil column height, but this type of static method is often not accurate and the results are inaccurate. Summary of the invention

[0005] The purpose of the present invention is to provide a method and a related device for determining the oil column height of a carbonate fault-karst reservoir, so as to solve the problem that static methods are often not accurate and the results are inaccurate.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for determining the oil column height of a carbonate fault-karst reservoir, comprising:

[0008] Collect temperature test data and geological data of oil wells in carbonate fault-controlled reservoirs to obtain static temperature test data at the initial stage of production and flow temperature test data on the scheduled production date;

[0009] Based on the above data, a wellbore-reservoir coupled thermodynamic physical model of fault-karst reservoirs is established;

[0010] Using the law of energy conservation, a wellbore temperature distribution model is established, and the bottom hole temperature is calculated from the wellhead temperature;

[0011] Then a one-dimensional vertical thermodynamic model of the reservoir is established, and the height from the bottom of the well to the bottom of the reservoir is obtained by iterative calculation by substituting the data of two temperature tests into the heat transfer model.

[0012] Finally, the calculated height is added to the height of the development layer drilled by the well to obtain the oil column height of the carbonate fault-karst reservoir.

[0013] Furthermore, based on the above data, a coupled thermodynamic physical model of wellbore and reservoir of fault-karst reservoir is established:

[0014] According to the fact that the heat transfer from the axis of the oil pipe to the formation during the production of crude oil is a steady one-dimensional heat transfer, the heat change per unit length of the microelement is obtained;

[0015]

[0016] Where, dQ is the heat change over the length of the microelement, kcal / h; dZ is the unit length, m; To is the temperature of the oil in the oil pipe, °C; T r - formation temperature, °C; R t -Thermal resistance from the tubing axis to the formation, kcal / (h·m·℃).

[0017] Furthermore, the energy conservation law is used to establish a wellbore temperature distribution model, and the bottom hole temperature is calculated from the wellhead temperature:

[0018] According to the heat loss of crude oil during wellbore production, such as Figure 1 As shown in the figure, the total thermal resistance R of the heat loss of crude oil in the wellbore is calculated. t and the total heat transfer coefficient U t ;

[0019] Taking the bottom of the well as the origin of the coordinate axis and setting the Z axis upward, the microelement at a distance of (n-1)dZ from the bottom of the well satisfies the energy conservation law. The heat Q(ndZ) transferred out of the microelement should be equal to the heat Q[(n-1)dZ] transferred into the microelement minus the heat lost by radial heat transfer, which can be described by the following expression:

[0020] Q ndZ =Q (n-1)dZ -Q 径传[(n-1)dZ]

[0021] Q ndZ =c o m o(n-1) T on

[0022] Q (n-1)dZ =c o m o(n-1) T o(n-1)

[0023] Q 径传[(n-1)dZ] =2πU t [T o (n-1)]dZ

[0024] In the formula, m o(n-1) -Mass of crude oil in microelement, kg; c o -Specific heat capacity of crude oil, J / (kg·℃); T o(n-1) - Temperature at the entrance of crude oil microelement, °C; T on -Crude oil microelement outlet temperature, °C; U t -The total heat transfer coefficient from the oil pipe axis to the formation, W / (m·℃).

[0025] The temperature expression of the formation where the microelement is located is obtained by using the ground temperature and the geothermal gradient:

[0026] T d(n-1) =T d +hZ0

[0027] Where, T d(n-1) -Temperature of the formation where the microelement is located, °C; T d - surface temperature, °C; Z0- geothermal gradient, °C / m; h- wellbore depth, m;

[0028] Substituting the above parameters into the formula of heat change of the microelement, we can get the microelement flow from the wellbore to the bottom of the well with respect to T o(n) The iterative formula is used, and VB programming is used for iterative calculation. The wellbore depth is divided into n micro-elements, and the bottom hole temperature is calculated from the wellhead temperature:

[0029]

[0030] Furthermore, the total thermal resistance R of the heat loss of crude oil in the wellbore is calculated. t and the total heat transfer coefficient U t :

[0031] Collect well data to obtain oil well parameter table, total thermal resistance R from the oil pipe axis to the formation t It is mainly composed of 5 parts: oil pipe thermal resistance R o , convection and radiation thermal resistance R inside the annulus h , sleeve thermal resistance R g , Cement ring thermal resistance R s , formation thermal resistance R d ;

[0032]

[0033] In the formula, λ 管 -thermal conductivity of the oil pipe, W / (m·℃); r1-inner diameter of the oil pipe, m; r2-outer diameter of the oil pipe, m; hc -Convection heat transfer coefficient, W / (m·℃); h r- Radiation heat transfer coefficient, W / (m·℃); λ casing-casing thermal conductivity, W / (m·℃); r 3- Casing inner diameter, m; r4-casing outer diameter, m; λ cement sheath-cement sheath thermal conductivity, W / (m·℃); r5-cement sheath outer diameter, m; λ formation-formation thermal conductivity, W / (m·℃); r6-formation outer diameter, m;

[0034] Sum up the thermal resistances in the calculation parameter table to get the complete expression of the thermal resistance from the tubing axis to the formation:

[0035] R t =R o +R h +R g +R s +R d

[0036]

[0037] The total heat transfer coefficient U from the tubing axis to the formation is obtained by the above thermal resistance expression t :

[0038]

[0039] Furthermore, a one-dimensional vertical thermodynamic model of the reservoir is established, and the two temperature test data are substituted into the heat transfer model, and the height from the bottom of the well to the bottom of the reservoir is iteratively calculated:

[0040] In the vertical direction, the microelement considers the one-dimensional heat conduction in the Z direction, and the energy conservation is obtained to obtain the thermodynamic differential equation;

[0041]

[0042] Initial condition: T(z,0) = T i (z) = T Ro -αz

[0043] Boundary conditions: T(0,t)=T Ro

[0044] Where, ξ(T)—thermal diffusion coefficient, m2 / s; T—temperature, °C; Z—the distance from any point in the vertical direction to the oil-water interface, m; α—geothermal gradient, °C / m;

[0045] Solve differential equations by separating variables, introducing eigenvalues, inverse Fourier transforms, and introducing error functions;

[0046] The semi-analytical expression of the temperature field is obtained by solving the problem. For point A at the bottom of the wellbore, we have

[0047]

[0048]

[0049] In the formula, h A —The height from the oil-water interface to the bottom of the well, m; T A1 —Initial bottom hole temperature °C; T A2 —The second test of the bottom temperature ℃; T Ro —Temperature at the oil-water interface ℃; t—production time d;

[0050] The model is programmed in VB, and the bottom hole temperature T of the two tests obtained from the wellbore thermodynamic model is A1 、T A2 Substitute into the formula for iterative calculation to obtain the height h from the oil-water interface to the bottom of the well. A .

[0051] Furthermore, the differential equation is solved by separating variables, introducing eigenvalues, inverse Fourier transform, and introducing error function:

[0052] Let θ(z,t)=T(z,t)-T ∞ , separating the variables of the differential equation gives:

[0053]

[0054] Introducing eigenvalue-β 2 , the above formula can be written as

[0055]

[0056] The general solution is obtained by introducing the characteristic function and superimposing it.

[0057]

[0058] After performing inverse Fourier transform on the above equation, substituting the boundary conditions into the equation, we can obtain

[0059]

[0060] Introducing the error function into the above formula, the above formula can be written as

[0061]

[0062] The series expansion of the error function is:

[0063] Furthermore, the calculated height is added to the height of the development layer drilled by the well to obtain the oil column height of the carbonate fault-karst reservoir:

[0064] The obtained height h A Add the height h of the target formation known from the drilling and completion data c Adding them together, we get the oil column height h of the reservoir.

[0065] h=h A +h c .

[0066] In a second aspect, the present invention provides a system for determining the oil column height of a carbonate fault-karst reservoir, comprising:

[0067] The data acquisition module is used to collect temperature test data and geological data of oil wells in carbonate fault-controlled reservoirs, and obtain static temperature test data at the initial stage of production and flow temperature test data on the scheduled production date;

[0068] A model building module is used to build a wellbore-reservoir coupled thermodynamic physical model of the fault-karst reservoir based on the above data;

[0069] The processing module is used to establish a wellbore temperature distribution model using the law of conservation of energy, and calculate the bottom hole temperature using the wellhead temperature; then establish a one-dimensional vertical thermodynamic model of the reservoir, substitute the two temperature test data into the heat transfer model, and iteratively calculate the height from the bottom of the well to the bottom of the reservoir; finally, the calculated height is added to the height of the development layer drilled by drilling to obtain the oil column height of the carbonate fault-karst reservoir.

[0070] In a third aspect, the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of a method for determining the oil column height of a carbonate fault-karst reservoir when executing the computer program.

[0071] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a method for determining the oil column height of a carbonate fault-karst reservoir.

[0072] Compared with the prior art, the present invention has the following technical effects:

[0073] The present invention determines a calculation method suitable for the oil column height of carbonate fault-karst reservoirs based on the wellbore-reservoir coupled thermodynamic model. The wellhead temperature data can be directly used to calculate the oil column height of the fault-karst reservoir, which solves the problem of large calculation errors of conventional static description methods and provides technical support for the judgment of the reserve scale of carbonate fault-karst reservoirs and their further development. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is a flow chart of the present invention;

[0075] Figure 2 It is a diagram of the wellbore-reservoir coupled thermodynamic physical model of a fault-karst reservoir;

[0076] Figure 3 It is a schematic diagram of heat loss during the production of crude oil in the wellbore;

[0077] Figure 4 It is a schematic diagram of energy conservation of microelement;

[0078] Figure 5 It is a schematic diagram of the reservoir thermodynamics micro-element heat transfer model. DETAILED DESCRIPTION

[0079] The present invention is further described below in conjunction with the accompanying drawings:

[0080] See also Figures 1 to 5 , Method for determining the oil column height of carbonate fault-karst reservoirs:

[0081] Collect temperature test data and geological data of a well in carbonate fault-karst reservoirs to obtain static temperature test data at the initial stage of production and flow temperature test data on the scheduled date of production (usually half a year or a year);

[0082] Establish a wellbore-reservoir coupled thermodynamic physical model for fault-karst reservoirs, such as Figure 1 As shown;

[0083] Using the law of energy conservation, a wellbore temperature distribution model is established, and the bottom hole temperature can be calculated from the wellhead temperature;

[0084] Then a one-dimensional vertical heat transfer model of the reservoir is established, and the height from the bottom of the well to the bottom of the reservoir is obtained by iterative calculation by substituting the data of two temperature tests into the heat transfer model.

[0085] Finally, the calculated height is added to the height of the development layer drilled by the well to obtain the oil column height of the carbonate fault-karst reservoir.

[0086] The detailed steps of the present invention are as follows:

[0087] Step S10, collecting temperature test data, geological data and drilling and completion data of a certain oil well in a carbonate fault-controlled oil reservoir, including static temperature test and flow temperature test, to obtain a wellhead temperature table of the oil well, as shown in Table 1;

[0088] Step S20: Based on the energy conservation principle of the microelement and the fact that the heat transfer from the axis of the oil pipe to the formation during the production of crude oil is a steady-state one-dimensional heat transfer, the heat change per unit length of the microelement can be obtained;

[0089]

[0090] Where, dQ is the heat change over the length of the microelement, kcal / h; dZ is the unit length, m; T o - Temperature of the oil in the oil pipe, °C; T r - formation temperature, °C; R t -Thermal resistance from the tubing axis to the formation, kcal / (h·m·℃).

[0091] Table 1 Sample table of temperature test data of an oil well in carbonate fault-karst reservoir

[0092]

[0093]

[0094] Step S30: According to the heat loss of crude oil during the wellbore production process, Figure 1 As shown in the figure, the total thermal resistance R of the heat loss of crude oil in the wellbore is calculated. t and the total heat transfer coefficient U t ;

[0095] Step S301, collect well data to obtain oil well parameter table, as shown in Table 2, the total thermal resistance R from the axis of the oil pipe to the formation t It is mainly composed of five parts: oil pipe thermal resistance (R o ), convection and radiation thermal resistance inside the annulus (R h )、Thermal resistance of the casing (R g ), cement ring thermal resistance (R s ), formation thermal resistance (R d );

[0096]

[0097] In the formula, λ 管 -thermal conductivity of the oil pipe, W / (m·℃); r1-inner diameter of the oil pipe, m; r2-outer diameter of the oil pipe, m; h c -Convection heat transfer coefficient, W / (m·℃); h r -Radiation heat transfer coefficient, W / (m·℃); λ 套管 -thermal conductivity of casing, W / (m·℃); r3-inner diameter of casing, m; r4-outer diameter of casing, m; λ 水泥环 -thermal conductivity of cement sheath, W / (m·℃); r5-outer diameter of cement sheath, m; λ 地层 - thermal conductivity of the formation, W / (m·℃); r6- outer diameter of the formation, m.

[0098] Table 2 Sample table of thermal resistance calculation parameters of a carbonate fault-karst reservoir oil well

[0099]

[0100]

[0101] Step S302, summing up the thermal resistances in the calculation parameter table, a complete expression of the thermal resistance from the axis of the oil pipe to the formation can be obtained;

[0102] R t =R o +R h +R g +R s +R d

[0103]

[0104] Step S303: The total heat transfer coefficient U from the oil pipe axis to the formation can be obtained through the above thermal resistance expression: t ;

[0105]

[0106] Step S40: Take the bottom of the well as the origin of the coordinate axis and let the Z axis point upward. Then the microelement at a distance of (n-1)dZ from the bottom of the well satisfies the following equation: Figure 2 According to the energy conservation shown, the heat Q(ndZ) transferred out of the microelement should be equal to the heat Q[(n-1)dZ] transferred into the microelement minus the heat lost by radial heat transfer, which can be described by the following expression;

[0107] Q ndZ =Q (n-1)dZ -Q 径传[(n-1)dZ]

[0108] Q ndZ =c o m o(n-1) T on

[0109] Q (n-1)dZ =c o m o(n-1) T o(n-1)

[0110] Q 径传[(n-1)dZ] =2πU t [T o (n-1)]dZ

[0111] In the formula, m o(n-1) -Mass of crude oil in microelement, kg; c o -Specific heat capacity of crude oil, J / (kg·℃); T o(n-1) - Temperature at the entrance of crude oil microelement, °C; T on -Crude oil microelement outlet temperature, °C; U t -The total heat transfer coefficient from the oil pipe axis to the formation, W / (m·℃).

[0112] Step S50, obtaining the formation temperature expression of the microelement through the ground temperature and the geothermal gradient;

[0113] T d(n-1) =T d +hZ0

[0114] Where, T d(n-1) -Temperature of the formation where the microelement is located, °C; T d -Surface temperature, °C; Z0-geothermal gradient, °C / m; h-wellbore depth, m.

[0115] Step S60: Substitute the above parameters into the formula of the heat change of the microelement to obtain the microelement of the flow from the wellbore to the bottom of the well with respect to T o(n) The iterative formula is used, and VB programming is used for iterative calculation. The wellbore depth is divided into n micro-elements, and the bottom hole temperature is calculated from the wellhead temperature.

[0116]

[0117] Step S70: Establish a reservoir thermodynamic model. In the vertical direction, the microelement considers one-dimensional heat conduction in the Z direction, such as Figure 3 As shown, the conservation of energy leads to the thermodynamic differential equation;

[0118]

[0119] Initial condition: T(z,0) = T i (z) = T Ro -αz

[0120] Boundary conditions: T(0,t)=T Ro

[0121] Where, ξ(T)—thermal diffusion coefficient, m 2 / s; T—temperature, ℃; Z—the distance from any point in the vertical direction to the oil-water interface, m; α—geothermal gradient, ℃ / m.

[0122] Step S80, solving the differential equation by separating variables, introducing eigenvalues, inverse Fourier transform, introducing error functions, etc.;

[0123] Step S801: Let θ(z,t)=T(z,t)-T ∞ , we can separate the variables of the differential equation to obtain;

[0124]

[0125] Step S802: Introducing eigenvalue-β 2 , the above formula can be written as;

[0126]

[0127] Step S803, introduce characteristic functions into the above equation and superimpose them to obtain a general solution;

[0128]

[0129] Step S804, perform inverse Fourier transform on the above equation and substitute the boundary conditions into it to obtain;

[0130]

[0131] Step S805: Introduce the error function into the above equation, and then the above equation can be written as:

[0132]

[0133] The series expansion of the error function is:

[0134] Step S90, solve and obtain the semi-analytical expression of the temperature field. For the bottom position of the wellbore (point A), we have:

[0135]

[0136]

[0137] In the formula, h A —Height from oil-water interface to bottom of well (m); T A1 —Initial bottom hole temperature (°C); T A2 —The second test bottom hole temperature (℃); T Ro —Temperature at the oil-water interface (℃); t—production time (d).

[0138] Step S100: Perform VB programming on the model, and calculate the bottom hole temperature T of the two tests obtained from the wellbore thermodynamic model. A1 、T A2 Substitute into the formula for iterative calculation to obtain the height h from the oil-water interface to the bottom of the well. A ;

[0139] Step S110: obtain the height h A Add the height h of the target formation known from the drilling and completion data c Adding them together, we can get the oil column height h of the reservoir;

[0140] h=h A +h c

[0141] Example:

[0142] Step S10, collecting temperature test data, geological data and drilling and completion data of well XX1 in carbonate fault-karst reservoir, obtaining relevant production data, and obtaining a temperature gradient table of the two tested oil wells, as shown in Table 3;

[0143] Table 3 Temperature test data of H1 oil well in carbonate fault-karst reservoir

[0144]

[0145]

[0146] Step S20: Based on the energy conservation principle of the microelement and the fact that the heat transfer from the axis of the oil pipe to the formation during the production of crude oil is a steady-state one-dimensional heat transfer, the heat change per unit length of the microelement can be obtained;

[0147]

[0148] Step S30: According to the heat loss of crude oil in the wellbore production process, the total thermal resistance R of the heat loss of crude oil in the wellbore is calculated. t and the total heat transfer coefficient U t ;

[0149] Step S301: Collect drilling data and survey related data of Well XX1 to obtain a table of thermal resistance calculation parameters for the oil well, as shown in Table 4. The total thermal resistance R from the axis of the oil pipe to the formation is t It is mainly composed of five parts: oil pipe thermal resistance (R o ), convection and radiation thermal resistance inside the annulus (R h )、Thermal resistance of the casing (R g ), cement ring thermal resistance (R s ), formation thermal resistance (R d );

[0150]

[0151] Table 4 Calculation parameters of thermal resistance of H1 oil well in carbonate fault-karst reservoir

[0152]

[0153]

[0154] Step S302, summing up the thermal resistances in the calculation parameter table, a complete expression of the thermal resistance from the axis of the oil pipe to the formation can be obtained;

[0155]

[0156] Step S303: The total heat transfer coefficient U from the oil pipe axis to the formation can be obtained by using the complete thermal resistance expression of the above steps: t ;

[0157]

[0158] Step S40: Divide the wellbore into n corresponding micro-elements according to the wellbore depth of 7400m, and calculate the o(n) The iterative formula is used to iterate, and the two test wellhead temperatures (35.6℃, 36.2℃) and related parameters are substituted into the calculation to obtain the two test bottom hole temperatures T A1 and T A2 .

[0159]

[0160]

[0161] Step S50, establishing a reservoir thermodynamic model, in the vertical direction, the microelement considers the one-dimensional heat conduction in the Z direction, and obtains the energy conservation to obtain the thermodynamic differential equation;

[0162]

[0163] Initial condition: T(z,0) = T i (z) = T Ro -αz

[0164] Boundary conditions: T(0,t)=T Ro

[0165] Step S60, solve and obtain the semi-analytical expression of the temperature field. For the bottom position of the wellbore (point A), we have:

[0166]

[0167] Step S60: Program the model and calculate the temperature T at the oil-water interface by default. ro =180℃, the bottom hole temperature T of the two tests obtained from the wellbore thermodynamic model A1 、T A2 Substitute into the formula for iterative calculation to obtain the height h from the oil-water interface to the bottom of the well. A .

[0168] h A =494.4m

[0169] Step S70: The height h of the target layer is known. c is 12 m, add the calculated hA to the height of the target formation h c Calculate the oil column height h of well XX1;

[0170] h=h A +h c =506.4m.

[0171] In yet another embodiment of the present invention, a system for determining the oil column height of a carbonate fault-karst reservoir is provided, which can be used to implement the above-mentioned method for determining the oil column height of a carbonate fault-karst reservoir. Specifically, the system comprises:

[0172] The data acquisition module is used to collect temperature test data and geological data of oil wells in carbonate fault-controlled reservoirs, and obtain static temperature test data at the initial stage of production and flow temperature test data on the scheduled production date;

[0173] A model building module is used to build a wellbore-reservoir coupled thermodynamic physical model of the fault-karst reservoir based on the above data;

[0174] The processing module is used to establish a wellbore temperature distribution model using the law of conservation of energy, and calculate the bottom hole temperature using the wellhead temperature; then establish a one-dimensional vertical thermodynamic model of the reservoir, substitute the two temperature test data into the heat transfer model, and iteratively calculate the height from the bottom of the well to the bottom of the reservoir; finally, the calculated height is added to the height of the development layer drilled by drilling to obtain the oil column height of the carbonate fault-karst reservoir.

[0175] The division of modules in the embodiments of the present invention is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present invention may be integrated into one processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0176] In another embodiment of the present invention, a computer device is provided, the computer device comprising a processor and a memory, the memory is used to store a computer program, the computer program comprises program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, which are suitable for implementing one or more instructions, and are specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the method for determining the oil column height of carbonate fault-karst reservoirs.

[0177] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both the built-in storage medium in the computer device and the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for determining the oil column height of the carbonate fault-karst reservoir in the above embodiment.

[0178] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0179] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0180] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0181] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0182] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for determining the oil column height of a carbonate fault-karst reservoir, characterized in that: include: Collect temperature test data and geological data of oil wells in carbonate fault-controlled reservoirs to obtain static temperature test data at the initial stage of production and flow temperature test data on the scheduled production date; Based on the above data, a wellbore-reservoir coupled thermodynamic physical model of fault-karst reservoirs is established; Using the law of energy conservation, a wellbore temperature distribution model is established, and the bottom hole temperature is calculated from the wellhead temperature; Then a one-dimensional vertical thermodynamic model of the reservoir is established, and the height from the bottom of the well to the bottom of the reservoir is obtained by iterative calculation by substituting the data of two temperature tests into the heat transfer model. Finally, the calculated height is added to the height of the development layer drilled by the well to obtain the oil column height of the carbonate fault-karst reservoir.

2. The method for determining the oil column height of a carbonate fault-karst reservoir according to claim 1, characterized in that: Based on the above data, a coupled thermodynamic physical model of wellbore and reservoir for fault-karst reservoirs is established: According to the fact that the heat transfer from the axis of the oil pipe to the formation during the production of crude oil is a steady one-dimensional heat transfer, the heat change per unit length of the microelement is obtained; Where, dQ is the heat change over the length of the microelement, kcal / h; dZ is the unit length, m; To is the temperature of the oil in the oil pipe, °C; T r - formation temperature, °C; R t -Thermal resistance from the tubing axis to the formation, kcal / (h·m·℃).

3. The method for determining the oil column height of a carbonate fault-karst reservoir according to claim 1, characterized in that: Using the law of energy conservation, a wellbore temperature distribution model is established, and the bottom hole temperature is calculated from the wellhead temperature: According to the heat loss of crude oil in the wellbore production process, as shown in Figure 1, the total thermal resistance R of the heat loss of crude oil in the wellbore is calculated. t and the total heat transfer coefficient U t ; Taking the bottom of the well as the origin of the coordinate axis and setting the Z axis upward, the microelement at a distance of (n-1)dZ from the bottom of the well satisfies the energy conservation law. The heat Q(ndZ) transferred out of the microelement should be equal to the heat Q[(n-1)dZ] transferred into the microelement minus the heat lost by radial heat transfer, which can be described by the following expression: Q ndZ =Q (n-1)dZ -Q 径传[(n-1)dZ] Q ndZ =c o m o(n-1) T on Q (n-1)dZ =c o m o(n-1) T o(n-1) Q 径传[(n-1)dZ] =2πU t [T o (n-1)]dZ In the formula, m o(n-1) -Mass of crude oil in microelement, kg; c o -Specific heat capacity of crude oil, J / (kg·℃); T o(n-1) - Temperature at the entrance of crude oil microelement, °C; T on -Crude oil microelement outlet temperature, °C; U t -Total heat transfer coefficient from the tubing axis to the formation, W / (m·℃); The temperature expression of the formation where the microelement is located is obtained by using the ground temperature and the geothermal gradient: T d(n-1) =T d +hZ0 Where, T d(n-1) -Temperature of the formation where the microelement is located, °C; T d - surface temperature, °C; Z0- geothermal gradient, °C / m; h- wellbore depth, m; Substituting the above parameters into the formula of heat change of the microelement, we can get the microelement flow from the wellbore to the bottom of the well with respect to T o(n) The iterative formula is used, and VB programming is used for iterative calculation. The wellbore depth is divided into n micro-elements, and the bottom hole temperature is calculated from the wellhead temperature:

4. The method for determining the oil column height of a carbonate fault-karst reservoir according to claim 3, characterized in that: The total thermal resistance R of the heat loss of crude oil in the wellbore is calculated t and the total heat transfer coefficient U t : Collect well data to obtain the oil well parameter table, the total thermal resistance R from the oil pipe axis to the formation t It is mainly composed of 5 parts: oil pipe thermal resistance R o , convection and radiation thermal resistance R inside the annulus h , sleeve thermal resistance R g , Cement ring thermal resistance R s , formation thermal resistance R d ; In the formula, λ 管 -thermal conductivity of the oil pipe, W / (m·℃); r1-inner diameter of the oil pipe, m; r2-outer diameter of the oil pipe, m; h c -Convection heat transfer coefficient, W / (m·℃); h r- Radiation heat transfer coefficient, W / (m·℃); λ casing-casing thermal conductivity, W / (m·℃); r 3- Casing inner diameter, m; r4-casing outer diameter, m; λ cement sheath-cement sheath thermal conductivity, W / (m·℃); r5-cement sheath outer diameter, m; λ formation-formation thermal conductivity, W / (m·℃); r6-formation outer diameter, m; Sum up the thermal resistances in the calculation parameter table to get the complete expression of the thermal resistance from the tubing axis to the formation: R t =R o +R h +R g +R s +R d The total heat transfer coefficient U from the tubing axis to the formation is obtained by the above thermal resistance expression t :

5. The method for determining the oil column height of a carbonate fault-karst reservoir according to claim 1, characterized in that: Then, a one-dimensional vertical thermodynamic model of the reservoir is established, and the two temperature test data are substituted into the heat transfer model, and the height from the bottom of the well to the bottom of the reservoir is obtained by iterative calculation: In the vertical direction, the microelement considers the one-dimensional heat conduction in the Z direction, and the energy conservation is obtained to obtain the thermodynamic differential equation; Initial condition: T(z,0) = T i (z) = T Ro -αz Boundary conditions: T(0,t)=T Ro Where, ξ(T)—thermal diffusion coefficient, m2 / s; T—temperature, °C; Z—the distance from any point in the vertical direction to the oil-water interface, m; α—geothermal gradient, °C / m; Solve differential equations by separating variables, introducing eigenvalues, inverse Fourier transforms, and introducing error functions; The semi-analytical expression of the temperature field is obtained by solving the problem. For point A at the bottom of the wellbore, we have In the formula, h A —The height from the oil-water interface to the bottom of the well, m; T A1 —Initial bottom hole temperature °C; T A2 —The second test of the bottom temperature ℃; T Ro —Temperature at the oil-water interface ℃; t—production time d; The model is programmed in VB, and the bottom hole temperature T of the two tests obtained from the wellbore thermodynamic model is A1 、T A2 Substitute into the formula for iterative calculation to obtain the height h from the oil-water interface to the bottom of the well. A .

6. The method for determining the oil column height of a carbonate fault-karst reservoir according to claim 5, characterized in that: Solve the differential equation by separating variables, introducing eigenvalues, inverse Fourier transform, and introducing error function steps: Let θ(z,t)=T(z,t)-T ∞ , separating the variables of the differential equation gives: Introducing eigenvalue-β 2 , the above formula can be written as The general solution is obtained by introducing the characteristic function and superimposing it. After performing inverse Fourier transform on the above equation, substituting the boundary conditions into the equation, we can obtain Introducing the error function into the above formula, the above formula can be written as The series expansion of the error function is:

7. The method for determining the oil column height of a carbonate fault-karst reservoir according to claim 1, characterized in that: Finally, the calculated height is added to the height of the development layer drilled by the well to obtain the oil column height of the carbonate fault-karst reservoir: The obtained height h A Add the height h of the target formation known from the drilling and completion data c Adding them together, we get the oil column height h of the reservoir. h=h A +h c 。 8. A system for determining the oil column height of a carbonate fault-karst reservoir, characterized in that: include: The data acquisition module is used to collect temperature test data and geological data of oil wells in carbonate fault-controlled reservoirs, and obtain static temperature test data at the initial stage of production and flow temperature test data on the scheduled production date; A model building module is used to build a wellbore-reservoir coupled thermodynamic physical model of the fault-karst reservoir based on the above data; The processing module is used to establish a wellbore temperature distribution model using the law of conservation of energy, and calculate the bottom hole temperature using the wellhead temperature; then establish a one-dimensional vertical thermodynamic model of the reservoir, substitute the two temperature test data into the heat transfer model, and iteratively calculate the height from the bottom of the well to the bottom of the reservoir; finally, the calculated height is added to the height of the development layer drilled by drilling to obtain the oil column height of the carbonate fault-karst reservoir.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for determining the oil column height of a carbonate fault-karst reservoir as claimed in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for determining the oil column height of a carbonate fault-karst reservoir as claimed in any one of claims 1 to 7 are implemented.

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