Method and device for predicting yield of fracturing reformed oil reservoir

Abstract

The invention discloses a method and device for predicting the yield of a fracturing reformed oil reservoir. The method comprises the steps that wellhead oil-gas-water and produced sand produced by an oil well of the fracturing reformed oil reservoir serve as the total produced solid-liquid volume; according to the volume of all produced solid and liquid, the underground converted volume of produced wellhead oil, gas and water and produced sand is determined; taking the volume sum of the underground fracturing fluid and the propping agent as the underground total volume; based on the fracturing construction parameters, according to the underground converted volume or the total output solid-liquid volume and the underground total volume, the underground total volume flowback rate is determined; establishing an oil well flowback rate and oil pressure accumulated oil production fitting prediction chart according to the oil well data of the flowback rate and the production dynamics; determining the oil well production state according to the morphological characteristics of the prediction plate; and according to the production state of the oil well and the linear segment characteristics of the prediction chart, the accumulated oil production of each oil well in the fracturing reformed oil reservoir is determined. The method can accurately predict the yield of the oil well in the fracturing reformed oil reservoir on the basis of the oil well flowback rate and the oil pressure accumulated oil production fitting prediction chart.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas field development, and particularly relates to a method and device for predicting the yield of a fractured and reconstructed reservoir. BACKGROUND

[0002] This section is intended to provide background information to facilitate an understanding of embodiments of the application as set forth in the claims. The description herein does not constitute admission of prior art.

[0003] With the continuous advancement of oilfield exploration and development, accurate yield trend recognition and research are of great significance for resource assessment, development planning and investment decision-making. Oilfield yield prediction plays a core role in the planning, decision-making and management of the oil industry. A large number of relevant literature studies show that with the progress of exploration and development technology, many scholars and research institutions have carried out a large number of studies on oil and gas field yield prediction methods.

[0004] The technology disclosed in patent No. CN119129159A relates to a method for predicting the yield of a horizontal well in a volumetrically fractured unconventional reservoir, which includes: obtaining the horizontal well parameters of a horizontal well to be predicted; obtaining the yield of a surrounding vertical well of the horizontal well to be predicted; constructing a horizontal well post-fracturing yield prediction formula for the horizontal well to be predicted; determining the coefficients of the horizontal well post-fracturing yield prediction formula; and calculating the yield of the horizontal well to be predicted. This method uses actual field data regression analysis method to calculate the yield of the horizontal well after volumetric fracturing, considers the influence of oil and gas enrichment degree and fracturing reconstruction degree on yield improvement effect, and reduces the difference in yield improvement effect of different blocks and different parts by introducing the yield of surrounding vertical wells, and has been well applied in low-grade oil reservoir exploration and development practice. However, by constructing an optimal classification hyperplane or a regression function to predict the yield, it has good generalization ability in the case of small samples, and can handle nonlinear relationships in shale oil yield prediction, but the selection and parameter optimization of the kernel function are difficult, and the fundamental reason is that vertical wells and horizontal development have essentially different principles and mechanisms. Compared with vertical wells, horizontal wells not only have differences in percolation mechanics principles, but also increase a series of engineering factors affecting the fracturing reconstruction process, and increase the percolation mechanics mechanism of reservoir matrix imbibition replacement, so the technology has the problem of low precision in predicting the yield of a fractured and reconstructed reservoir.

[0005] The technology disclosed in patent publication CN110175412A relates to an oil reservoir data fitting method, which comprises the following steps: obtaining pressure data and pressure related data according to multiple groups of measured oil reservoir data; determining key data nodes in the pressure related data according to the change trend of the pressure related data; dividing first change trend information formed by the pressure data and second change trend information formed by the pressure related data into multiple data segments according to the key data nodes; matching a corresponding target data segment for each target parameter to be determined in a target oil reservoir model from the multiple data segments; taking the target data segment corresponding to each target parameter as calibration data to fit each target parameter to be determined, so as to determine the target oil reservoir model. The oil reservoir data fitting method matches the multiple data segments in the two kinds of change trend information to calibrate different target parameters, can specifically fit the target parameters, and thus can improve the convergence speed of fitting and the fitting speed of the oil reservoir model. However, the simulation method depends on a relatively reliable data system, and it is difficult to study a fracturing system with strong uncertainty. In addition, it is difficult for numerical simulation to represent a dynamically changing drainage volume and flow channel. The core mechanism of the patent technology lies in using the measured pressure as a dependent parameter. On the one hand, the pressure is affected by wellbore flow and choke, and is a dynamic variable. The prediction of the yield, especially the cumulative yield, is a volume parameter. Therefore, the selection of the dependent parameter based on the patent technology limits the reliability of the prediction result, and thus the technology also has the problem of low prediction accuracy of the yield of the fracturing transformed oil reservoir.

[0006] In summary, the prior art has the technical problem of being unable to accurately predict the yield of the fracturing transformed oil reservoir. SUMMARY

[0007] The embodiment of the present application provides a method for predicting the yield of a fracturing transformed oil reservoir, which is used for accurately predicting the yield of the fracturing transformed oil reservoir based on the well flowback rate and the oil pressure cumulative oil fitting prediction chart. The method comprises the following steps:

[0008] The wellhead oil, gas, water and sand produced by the oil well of the fracturing transformed oil reservoir are taken as the total output solid-liquid volume. The in-situ conversion volume of the wellhead oil, gas, water and sand produced is determined according to the total output solid-liquid volume.

[0009] The volume of the fracturing fluid and the proppant entering the ground is taken as the total volume entering the ground. The total volume entering the ground is determined according to the in-situ conversion volume or the total output solid-liquid volume and the total volume entering the ground based on the fracturing construction parameters.

[0010] The fracturing transformed oil reservoir well flowback rate and oil pressure cumulative oil fitting prediction chart is established according to the flowback rate and the oil well data of the production dynamic.

[0011] Determine the production state of the oil well according to the shape characteristics of the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart;

[0012] Determine the cumulative oil production of each oil well in the fracturing reservoir according to the production state of the oil well and the linear segment characteristics of the prediction chart.

[0013] The embodiment of the present application also provides a device for predicting the yield of the fracturing reservoir, which is used for accurately predicting the yield of the fracturing reservoir based on the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart, and the device comprises:

[0014] The underground conversion volume determination unit is used for taking the wellhead oil, gas, water and sand produced by the oil well in the fracturing reservoir as the total output solid-liquid volume, and determining the underground conversion volume of the wellhead oil, gas, water and sand produced according to the total output solid-liquid volume.

[0015] The flowback rate determination unit is used for taking the volume of the fracturing fluid and the proppant as the total volume, and determining the total volume flowback rate according to the underground conversion volume or the total output solid-liquid volume and the total volume based on the fracturing construction parameters.

[0016] The chart establishment unit is used for establishing the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart according to the flowback rate and the oil well data of the production dynamic.

[0017] The production state determination unit is used for determining the production state of the oil well according to the shape characteristics of the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart.

[0018] The cumulative oil production determination unit is used for determining the cumulative oil production of each oil well in the fracturing reservoir according to the production state of the oil well and the linear segment characteristics of the prediction chart.

[0019] The embodiment of the present application also provides a computer device, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, and the processor realizes the fracturing reservoir yield prediction method when executing the computer program.

[0020] The embodiment of the present application also provides a computer readable storage medium, which stores a computer program, and the computer program realizes the fracturing reservoir yield prediction method when executed by the processor.

[0021] The embodiment of the present application also provides a computer program product, which comprises a computer program, and the computer program realizes the fracturing reservoir yield prediction method when executed by the processor.

[0022] Compared with the technical scheme that cannot accurately predict the production of the fractured reservoir in the prior art, the scheme for predicting the production of the fractured reservoir in the embodiment of the present application has the following advantages: the wellhead oil, gas, water and sand produced by the oil well of the fractured reservoir are taken as the total output solid-liquid volume; the underground converted volume of the wellhead oil, gas, water and sand produced is determined according to the total output solid-liquid volume; the volume of the fracturing fluid and the proppant into the ground is taken as the total volume into the ground; the total volume into the ground flowback rate is determined according to the underground converted volume or the total output solid-liquid volume and the total volume into the ground based on the fracturing construction parameters; the fracturing reservoir oil well flowback rate and oil pressure cumulative oil fitting prediction graph is established according to the flowback rate and the oil well data of the production performance; the oil well production state is determined according to the morphological characteristics of the fracturing reservoir oil well flowback rate and oil pressure cumulative oil fitting prediction graph; and the cumulative oil production of each oil well in the fractured reservoir is determined according to the oil well production state and the linear segment characteristics of the prediction graph, so that the production of the fractured reservoir can be accurately predicted based on the oil well flowback rate and oil pressure cumulative oil fitting prediction graph, and the accuracy of the production prediction of the fractured reservoir is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort. In the drawings:

[0024] Figure 1 The flowchart of the method for predicting the production of the fractured reservoir in the embodiment of the present application is shown in the figure;

[0025] Figure 2 The schematic diagram of the relationship between the oil pressure and the flowback rate in the embodiment of the present application is shown in the figure;

[0026] Figure 3 The schematic diagram of the relationship between the cumulative oil production and the flowback rate in the embodiment of the present application is shown in the figure;

[0027] Figure 4 The schematic diagram of the fracturing channeling of the fractured oil well in the embodiment of the present application is shown in the figure;

[0028] Figure 5 The schematic diagram of the repeated fracturing of the fractured oil well in the embodiment of the present application is shown in the figure;

[0029] Figure 6 The schematic diagram of the stable change of the oil pressure with the flowback rate in the embodiment of the present application is shown in the figure;

[0030] Figure 7 The schematic diagram of the pressure of the fracturing channeling oil well in the embodiment of the present application is shown in the figure;

[0031] Figure 8 A pressure diagram of a repeatedly fractured oil well in the embodiment of the present application;

[0032] Figure 9 A pressure diagram of an oil well with a changed production system in the embodiment of the present application;

[0033] Figure 10 A pressure diagram of an oil well with a low oil pressure in the embodiment of the present application;

[0034] Figures 11A-11C A fitting prediction chart of cumulative oil production of a fractured production well in the embodiment of the present application;

[0035] Figure 12 A structure diagram of a device for predicting the production of a fractured reservoir in the embodiment of the present application. DETAILED DESCRIPTION

[0036] To make the purpose, technical scheme and advantages of the embodiment of the present application clearer and more apparent, the embodiment of the present application is further described in detail below with reference to the drawings. Herein, the schematic embodiment of the present application and its description are used to explain the present application, but not as a limitation to the present application.

[0037] The acquisition, storage, use, processing and the like of data in the technical scheme of the present application all comply with the relevant provisions of laws and regulations.

[0038] Considering the technical problems existing in the prior art, how to establish a relatively stable and reliable mathematical model and find the law of production change when the field of pressure or fracturing reconstruction changes is a real problem to be solved. Therefore, the embodiment of the present application proposes a scheme for predicting the production of a fractured reservoir. The scheme for predicting the production of a fractured reservoir is described in detail below.

[0039] Figure 1 A flowchart of a method for predicting the production of a fractured reservoir in the embodiment of the present application, as shown in Figure 1 The method comprises the following steps:

[0040] Step 101: Taking the wellhead oil, gas, water and sand produced by the fractured reservoir oil well as the total output solid-liquid volume; determining the underground converted volume of the wellhead oil, gas, water and sand produced according to the total output solid-liquid volume;

[0041] Step 102: Taking the volume of the fracturing fluid and proppant into the ground as the total volume into the ground; determining the total volume into the ground flowback rate based on the fracturing construction parameters, the underground converted volume or the total output solid-liquid volume, and the total volume into the ground;

[0042] Step 103: Establishing a fracturing reservoir well flowback rate and oil pressure cumulative oil production fitting prediction chart according to the flowback rate and the oil well data of production dynamics.

[0043] Step 104: determining the production state of the oil well according to the shape characteristics of the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart;

[0044] Step 105: determining the cumulative oil production of each oil well in the fracturing reservoir according to the production state of the oil well and the characteristics of the straight line segment of the prediction chart.

[0045] The method for predicting the production of the fracturing reservoir provided by the embodiment of the present application works as follows: taking the wellhead oil, gas, water and sand produced by the oil well in the fracturing reservoir as the total output solid-liquid volume; determining the underground conversion volume of the wellhead oil, gas, water and sand produced according to the total output solid-liquid volume; taking the volume of the fracturing fluid and the proppant as the total volume of the earth; determining the total volume of the earth return rate based on the fracturing construction parameters, the underground conversion volume or the total output solid-liquid volume, and the total volume of the earth; establishing the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart according to the flowback rate and the oil well data of the production dynamic; determining the production state of the oil well according to the shape characteristics of the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart; and determining the cumulative oil production of each oil well in the fracturing reservoir according to the production state of the oil well and the characteristics of the straight line segment of the prediction chart.

[0046] Compared with the technical scheme in the prior art which cannot accurately predict the production of the fracturing reservoir, the method for predicting the production of the fracturing reservoir provided by the embodiment of the present application can accurately predict the production of the fracturing reservoir based on the oil well flowback rate and the oil pressure cumulative oil production fitting prediction chart, thereby improving the accuracy of the prediction of the production of the fracturing reservoir. The method for predicting the production of the fracturing reservoir will be described in detail below.

[0047] In order to solve the problems in the prior art, the embodiment of the present application realizes the reservoir and single well dynamic understanding close to the production practice, refers to the curve characteristics on the part of the cumulative value chart in the water drive characteristic curve, and establishes a straight line chart completely different from the water drive characteristic curve through multiple attempts. First, the total volume of the fracturing fluid and the proppant pressed into the earth is taken as the total volume of the earth, and the oil, gas, water and sand discharged from the wellhead are taken as the total discharge volume. The ratio of the two is referred to as the total volume of the earth return rate, which is referred to as the flowback rate. Through statistical analysis, it is found that the pressure straight line segment and the cumulative production straight line segment are often formed on the flowback rate chart after the fracturing production well, and the fracturing reservoir production prediction method is established combining the characteristics of the two straight line segments. The specific technical scheme process is as follows:

[0048] (1) The cumulative output fluid underground conversion volume of the wellhead is calculated by comprehensively considering the oil, water and gas production, that is, step 101.

[0049] The wellhead oil, gas and water production of the oil well of the oil reservoir is different in the underground volume under the influence of high temperature and high pressure, the patent mainly considers the underground fluid flow, and therefore needs to be combined with the oil reservoir engineering to convert the wellhead oil, gas and water and sand production to the underground, so as to facilitate the calculation of the deep suction effect of the fracturing fluid replacing the crude oil.

[0050] In a specific implementation, the underground volume of the produced water is calculated by using the formation water volume coefficient B w The calculation (formula 1-2) that determines the underground converted volume of the produced wellhead oil, gas, water and sand according to the total produced solid-liquid volume in an embodiment can include: the underground converted volume of the produced water is calculated by using the formation water volume coefficient.

[0051] In a specific implementation, the underground volume of the produced oil is calculated by using the underground crude oil volume coefficient B o The calculation (formula 3-4) that determines the underground converted volume of the produced wellhead oil, gas, water and sand according to the total produced solid-liquid volume in an embodiment can include: the underground converted volume of the produced oil is calculated by using the underground crude oil volume coefficient.

[0052] In a specific implementation, if the underground oil reservoir is saturated, the produced gas is calculated by using the produced gas state equation combined with the dissolved gas-oil ratio (formula 5-9), and if the underground oil reservoir is not saturated, the produced gas exists in the form of dissolved gas in the underground and is included in the calculation of the underground volume coefficient of the crude oil, without additional calculation. The calculation (formula 5-9) that determines the underground converted volume of the produced wellhead oil, gas, water and sand according to the total produced solid-liquid volume in an embodiment can include: if the underground oil reservoir is saturated, the underground converted volume of the produced gas is calculated by using the produced gas state equation combined with the dissolved gas-oil ratio; and if the underground oil reservoir is not saturated, the underground converted volume of the produced gas exists in the form of dissolved gas in the underground and is included in the calculation of the underground volume coefficient of the crude oil, without additional calculation.

[0053] In a specific implementation, if the produced well produces sand (proppant quartz sand, etc.), the underground additional discharge volume is converted by using the relationship between the produced sand mass and the density or by using the relationship between the sand volume and the sand pore volume. The calculation (formula 6-7) that determines the underground converted volume of the produced wellhead oil, gas, water and sand according to the total produced solid-liquid volume in an embodiment can include: if the produced well produces sand, the underground converted volume of the produced sand is converted by using the relationship between the produced sand mass and the density or by using the relationship between the sand volume and the sand pore volume.

[0054] (1)

[0055] (2)

[0056] (3)

[0057] (4)

[0058] (5)

[0059] (6)

[0060] (7)

[0061] (8)

[0062] (9)

[0063] (10)

[0064] Volume of crude oil at pressure P and temperature T, m 3 ;

[0065] Volume of crude oil after degassing at surface conditions (20°C, 0.1 MPa), m 3 ;

[0066] Volume factor of formation water, decimal

[0067] Volume of formation water at reservoir conditions, m 3 ;

[0068] Volume of this formation water at surface conditions, m 3 ;

[0069] Volume factor of natural gas, m 3 / m 3 ;

[0070] Volume of the quantified natural gas at standard conditions, m 3 ;

[0071] Volume of the quantified natural gas at reservoir conditions, m 3 ;

[0072] Density at the temperature and pressure of the gas reservoir, kg / m 3 ;

[0073] Density at surface standard conditions, kg / m 3 ;

[0074] — pressure of natural gas at standard conditions;

[0075] — volume of natural gas at standard conditions;

[0076] — temperature of natural gas at standard conditions;

[0077] t — temperature of oil and gas layer, ℃;

[0078] — original dissolved gas-oil ratio of formation oil, m 3 / m 3 ;

[0079] — dissolved gas-oil ratio at pressure P, m 3 / m 3 ;

[0080] — volume of degassed surface crude oil, m 3 ;

[0081] — volume at surface conditions, m 3 ;

[0082] — volume at formation conditions, m 3 ;

[0083] — compressibility factor, unit usually Pa -1 ;

[0084] — volumetric thermal expansion coefficient, 1 / ℃;

[0085] — pressure change from surface to formation, MPa;

[0086] — temperature change from surface to formation, ℃.

[0087] The above parameters constitute the total volume discharged from the formation in the whole chain production process after well fracturing.

[0088] (2) Combined with the fracturing construction parameters, the volume of the solid discharged from the well is calculated, that is, the above step 102.

[0089] Due to the complex underground features of unconventional reservoirs, and the uncertainty of fracturing reconstruction, the complexity of the fracture network structure is formed, and the double complexity greatly increases the uncertainty of reservoir modeling after fracturing, so that the natural decline and numerical simulation methods suitable for conventional reservoirs lose their basis. However, during the fracturing process, the sanding amount, pump speed, pressure, fracturing fluid composition, segment number, cluster number, segment spacing, cluster spacing and the like have an influence on the fracturing fluid flowback, and this influence is relatively easy to predict, that is, in an embodiment, the fracturing operation parameters can include one or any combination of sanding amount, pump speed, pressure, fracturing fluid composition, segment number, cluster number, segment spacing or cluster spacing, which are used to distinguish the classification form features of the typical curve, and are used to predict the selection of the segment interval. Therefore, combined with the fracturing operation situation, if the fracturing is one-time fracturing, the total volume of the fracturing fluid and the proppant volume into the ground are taken as the total volume into the ground, and the in-situ converted volume of the produced oil, gas and water and the sand is taken as the molecule to obtain the fracturing operation total volume into the ground flowback rate R (formula 11); if repeated fracturing occurs, the total volume of the fracturing fluid into the ground is taken as the denominator, and the total produced solid-liquid volume is taken as the molecule to calculate the flowback rate (formula 12), at this time the flowback rate often occurs at the fracturing time point. Return, thereby affecting the form features of the pressure graph and the cumulative production graph. In the embodiment of the present application, the calculation of the flowback rate is carried out by taking the in-situ volume as the target, that is, how much is injected into the ground, and how much is returned to the ground, to see the production condition at the time of 100% flowback rate, which also helps to observe the occurrence of in-situ imbibition.

[0090] As can be seen from the above, in an embodiment, the total volume into the ground flowback rate is determined according to the in-situ converted volume or the total produced solid-liquid volume, and the total volume into the ground, which can include:

[0091] Combined with the fracturing operation situation, if the fracturing is one-time fracturing, the total volume into the ground is taken as the denominator, and the in-situ converted volume is taken as the molecule to obtain the fracturing operation total volume into the ground flowback rate;

[0092] If repeated fracturing occurs, Figure 5 In the embodiment of the present application, the repeated fracturing schematic diagram of the fracturing oil well is shown, the total volume into the ground of at least two times of fracturing is taken as the denominator, and the total produced solid-liquid volume is taken as the molecule to determine the total volume into the ground flowback rate.

[0093] (11)

[0094] (12)

[0095] R --- flowback rate;

[0096] V out --- cumulative production volume, m3 ;

[0097] V in Total volume of the ground, m 3 ;

[0098] V wd Volume of the liquid into the ground, m 3 ;

[0099] V sd Volume of the proppant into the ground, m 3 ;

[0100] V oR Underground volume of cumulative oil production, m 3 ;

[0101] V gR Underground volume of cumulative gas production, m 3 ;

[0102] V wR Underground volume of cumulative water production, m 3 ;

[0103] V sR Underground volume of sand production, m 3 .

[0104] (3) Combined with dynamic data and monitoring data, a single well flowback rate-wellhead oil pressure / cumulative oil production chart (as shown in Figures 11A-11C ) is established, that is, the above step 103.

[0105] Figure 2 is a schematic diagram of the relationship between oil pressure and flowback rate in the embodiment of the present application, that is, a flowback rate-wellhead oil pressure chart. Figure 3 is a schematic diagram of the relationship between cumulative oil production and flowback rate in the embodiment of the present application, that is, a flowback rate-cumulative oil production chart. Figure 2 and Figure 3 , an oil pressure-cumulative oil production fitting prediction chart as shown in Figures 11A-11C is constructed, and the linear trend existing between the cumulative oil production and the oil pressure can be used as the chart. Figures 11A-11C is a fracturing production well oil pressure-cumulative oil production fitting prediction chart in the embodiment of the present application, that is, a fracturing reservoir oil well flowback rate-oil pressure-cumulative oil production fitting prediction chart. Figures 11A-11C In the chart, X represents the flowback rate; in the increasing trend line formula, Y represents the cumulative oil production; and in the decreasing trend line formula, Y represents the oil pressure.

[0106] In the above step 103, in one embodiment, according to the flowback rate and the oil well data of production dynamics, the fracturing reservoir oil well flowback rate-oil pressure-cumulative oil production fitting prediction chart can be established, which can include: using the flowback rate as the horizontal axis to construct the prediction chart.

[0107] In actual implementation, the reason why the flowback rate is used as the horizontal axis to construct the graph is that the general permeability of the fractured production well is not high, the formation pressure transmission height depends on the fracture network system, and thus the wellhead pressure is relatively high in the early stage and the production is relatively high, and then the pressure decreases rapidly, which causes the production to decrease rapidly. After the flowback rate graph is used, the wellhead pressure change in the early stage and the late stage can be reduced to make the production fluctuate, so it is difficult to predict. In addition, due to the problems such as sand plugging and salt plugging in the fracturing, the well is shut down, which also causes the wellhead pressure change or the continuity of the production to be damaged, thereby affecting the stability of the calculation and operation of the natural decline and numerical simulation. It can be seen from the use of the graph that the pressure and the volume of the material injected into the formation can form a good straight line relationship, and the actual data verifies the stability of this data trend. Figure 2 、 Figure 4

[0108] In actual implementation, in the embodiment of the present application, the dynamic data can be dynamic change data such as oil well oil production and liquid production, and the monitoring data is mainly pressure, and there can also be output profile and along-the-way output intensity monitoring (profile data is rare).

[0109] In actual implementation, in one embodiment, the method for predicting the production of the fractured reservoir can further include: when a major measure such as salt plugging and sand plugging removal and repeated fracturing occurs, the flowback rate and the oil pressure cumulative oil fitting prediction graph needs to be updated, the equation corresponding to the straight line segment of the oil pressure-flowback rate and the cumulative oil-flowback rate is re-made, and a new prediction template is established.

[0110] (4) Determine the production state of the oil well according to the shape characteristics of the comprehensive pressure graph, that is, the above step 104.

[0111] In the above step 104, in one embodiment, the production state of the oil well is determined according to the shape characteristics of the flowback rate and the oil pressure cumulative oil fitting prediction graph of the fractured reservoir oil well, which can include: the production state of the oil well is determined according to the following shape characteristics of the flowback rate and the oil pressure cumulative oil fitting prediction graph of the fractured reservoir oil well:

[0112] When the oil pressure changes with the increase of the flowback rate within a preset range, the pressure characteristics of the fractured well in the late stage are presented; the straight line segment is interrupted in the production process and presents a new straight line segment with different slopes; when the flowback rate returns and the pressure rises by more than a preset amplitude value, the flowback rate and pressure data characteristics are presented; when the size of the oil nozzle is changed, the slope of the straight line segment is changed or other pressure fluctuations are presented; when the oil pressure is lower than zero and the flowback rate continues to increase but the oil pressure is low, the actual converted formation pressure is decreased by more than a preset amplitude value.

[0113] In actual implementation, the following five or more shape characteristics can be presented on the pressure graph: first, the pressure changes stably with the increase of the flowback rate, which is the pressure characteristic of the fractured well in the late stage (​Figure 6 ) ; the second is that the straight line segment is broken in the production process, and presents a new straight line segment with different slope, because the oil pressure is greatly increased due to the fracturing of other surrounding wells and the channeling into the fracture system of the well ( Figure 7 ) ; the third is that the flowback rate returns and the flowback rate and pressure data characteristics when the pressure exceeds the preset amplitude value, because the repeated fracturing of the well affects the flowback rate and pressure data ( Figure 8 ) ; the fourth is to change the size of the choke, so that the slope of the straight line segment changes or other pressure fluctuates ( Figure 9 ) ; the fifth is that the flowback rate continues to increase but the oil pressure runs at a low level when the oil pressure is lower than zero and the actual converted formation pressure is greatly reduced ( Figure 10 ). According to the five morphological characteristics, the straight line segment is determined, the flowback rate of the well fluid is extrapolated, and the cumulative oil production is extrapolated.

[0114] (5) According to the straight line segment characteristics of the oil pressure and cumulative production graph, the straight line segment is determined, the flowback rate of the well fluid is extrapolated, and the cumulative oil production is extrapolated, that is, the above step 105.

[0115] In the above step 105, in an embodiment, according to the production state of the oil well and the straight line segment characteristics of the predicted graph, the cumulative oil production of each oil well in the fractured reservoir can include:

[0116] According to the production state of the oil well and the fractured reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction graph, the preferred straight line segment characteristics are determined;

[0117] According to the straight line segment characteristics of the oil pressure and cumulative production, the straight line equation of the oil pressure straight line segment and the cumulative oil production straight line segment is established;

[0118] According to the straight line equation of the oil pressure straight line segment and the cumulative oil production straight line segment, the natural flowback rate limit value when the oil pressure is zero is predicted;

[0119] The natural flowback rate limit value of the oil well is substituted into the straight line equation to determine the natural flowback cumulative oil production of each oil well in the fractured reservoir.

[0120] In specific implementation, the single-well oil pressure and cumulative production comprehensive graph (as shown in Figures 11A-11C , the fractured reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction graph) is taken as a reference, the production state is combined, the appropriate straight line stage is selected, the straight line equation of the pressure straight line segment and the cumulative straight line segment is fitted and established, the linear trend line is drawn for the straight line segment, and the trend line equation is taken as the straight line segment equation. According to the straight line equation, the natural flowback rate limit value when the oil pressure is zero is predicted, the natural flowback rate limit value of the oil well is substituted into the straight line equation, and the natural flowback cumulative oil production of each oil well in the fractured reservoir is determined (as shown in Figures 11A-11C ).

[0121] In a specific implementation, in combination with the production state, a suitable straight line stage is selected, and in order to more accurately predict the flowback multiple of the oil well under the condition of zero oil pressure, the embodiment of the present application can determine that the dimensionless oil pressure is in the interval of 0.02 to 0.2 as the key production period of oil well fitting. Since the production states of various wells are not the same, in this interval, a smaller production period is selected for each well, so as to improve the accuracy of prediction.

[0122] In a specific implementation, according to the characteristics of the straight line segment of the oil pressure and cumulative production graph, the straight line segment is determined, the flowback rate of the well material is extrapolated, and the cumulative oil production is extrapolated, for example, as shown in Figures 11A-11C After the straight line segment is determined, the linear fitting of the straight line segment is performed, and the trend line is extended to predict the flowback rate of the final oil well abandonment and the cumulative oil production under the flowback rate.

[0123] (6) Statistical analysis of the flowback rate and the predicted cumulative oil production of each well, analysis of the influencing factors of oil well production, that is, the further preferred scheme of the embodiment of the present application.

[0124] In one embodiment, the method for predicting the production of the fractured reservoir can further include: determining the cumulative oil production of all oil wells in a preset research area of the fractured reservoir according to the cumulative oil production of each oil well in the fractured reservoir.

[0125] In a specific implementation, the flowback rate and the cumulative oil production of all oil wells are statistically analyzed, and the proportional relationship of different types of oil wells is statistically analyzed, so as to form an understanding of the production state of the oil wells in the overall block. Specifically, the proportional relationship can be to count the number of different types of oil wells to form a proportional relationship, which can include: stable change of oil pressure with flowback rate, fracturing channeling type, repeated fracturing, production system change, and low position operation of oil pressure.

[0126] In the embodiment of the present application, the data of the oil company in multiple regions is collected, and a graph is established. In the actual oil field application of multiple oil fields, it is confirmed that the law is generally present, and can be used to predict the production and for the production application of the fractured reservoir evaluation and the like.

[0127] The embodiment of the present application further provides a device for predicting the production of the fractured reservoir, as described in the following embodiment. Since the principle of solving the problem of the device is similar to that of the method for predicting the production of the fractured reservoir, the implementation of the device can be referred to the implementation of the method for predicting the production of the fractured reservoir, and the repeated parts will not be described herein.

[0128] Figure 12 The structure diagram of the device for predicting the production of the fractured reservoir in the embodiment of the present application is shown in Figure 12 The device includes:

[0129] The underground conversion volume determination unit 01 is configured to take the wellhead oil, gas, water and sand production of the fractured reservoir well as the total solid-liquid volume, and determine the underground conversion volume of the wellhead oil, gas, water and sand production according to the total solid-liquid volume.

[0130] The flowback rate determination unit 02 is configured to take the volume of the fracturing fluid and the proppant as the total volume, and determine the total volume flowback rate according to the underground conversion volume or the total solid-liquid volume, and the total volume based on the fracturing construction parameters.

[0131] The chart establishment unit 03 is configured to establish a fracturing reservoir well flowback rate and oil pressure cumulative oil fitting prediction chart according to the flowback rate and the oil well data of the production dynamic.

[0132] The production state determination unit 04 is configured to determine the oil well production state according to the shape features of the fracturing reservoir well flowback rate and oil pressure cumulative oil fitting prediction chart.

[0133] The cumulative oil production determination unit 05 is configured to determine the cumulative oil production of each oil well in the fractured reservoir according to the oil well production state and the linear segment features of the prediction chart.

[0134] In one embodiment, the cumulative oil production determination unit is specifically configured to:

[0135] determine the preferred linear segment features according to the oil well production state and the fracturing reservoir well flowback rate and oil pressure cumulative oil fitting prediction chart;

[0136] establish the oil pressure linear segment and the cumulative oil linear segment linear equation according to the preferred linear segment features;

[0137] predict the natural flowback rate limit value when the oil pressure is zero according to the oil pressure linear segment and the cumulative oil linear segment linear equation;

[0138] determine the natural flowback cumulative oil production of each oil well in the fractured reservoir by substituting the oil well natural flowback rate limit value into the linear equation.

[0139] In one embodiment, the production state determination unit is specifically configured to determine the oil well production state according to the following shape features of the fracturing reservoir well flowback rate and oil pressure cumulative oil fitting prediction chart:

[0140] The pressure characteristics presented in the later stage of fracturing well when the oil pressure changes with the increase of the flowback rate within the preset range; the straight line segment is interrupted in the production process, and a new straight line segment with different slope is presented; the flowback rate and pressure data characteristics when the pressure rises more than the preset amplitude value when the flowback rate returns; the characteristics of changing the choke size to change the slope of the straight line segment or other pressure fluctuations; the characteristics that the flowback rate continues to increase when the oil pressure is lower than zero, but the oil pressure runs at a low level, and the actual converted formation pressure decreases more than the preset amplitude value.

[0141] In one embodiment, the flowback rate determination unit is specifically configured to:

[0142] In combination with the fracturing construction situation, if the fracturing is one-time fracturing, the total volume of the ground is taken as the denominator, and the underground converted volume is taken as the numerator to obtain the total volume of the ground flowback rate changing with time.

[0143] If repeated fracturing occurs, the total volume of the ground of at least two fracturing is taken as the denominator, and the total output solid-liquid volume is taken as the numerator to determine the total volume of the ground flowback rate.

[0144] In one embodiment, the graph building unit is specifically configured to: build the prediction graph with the flowback rate as the horizontal axis.

[0145] In one embodiment, the underground converted volume determination unit is specifically configured to: if the underground oil reservoir is saturated, the underground converted volume of the output gas is calculated using the output gas state equation combined with the dissolved gas-oil ratio; if the underground oil reservoir is not saturated, the underground converted volume of the output gas exists in the form of dissolved gas in the underground and is included in the calculation of the crude oil underground volume coefficient, without additional calculation.

[0146] In one embodiment, the underground converted volume determination unit is specifically configured to: the underground converted volume of the output water is calculated using the formation water volume coefficient.

[0147] In one embodiment, the underground converted volume determination unit is specifically configured to: the underground converted volume of the output oil is calculated using the underground crude oil volume coefficient.

[0148] In one embodiment, the underground converted volume determination unit is specifically configured to: if the sand production well produces sand, the underground converted volume of the sand production is converted from the relationship between the mass and the density of the sand production or from the volume of the sand production and the pore volume of the sand production.

[0149] In one embodiment, the fracturing construction parameters include one or any combination of sanding amount, pump speed, pressure, fracturing fluid composition, segment number, cluster number, segment spacing, or cluster spacing.

[0150] In one embodiment, the device for predicting the production of the fractured reservoir can further comprise an overall condition determining unit configured to determine the cumulative oil production of all the oil wells in the preset research area of the fractured reservoir according to the cumulative oil production of each oil well in the fractured reservoir.

[0151] The embodiment of the present application further provides a computer device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the method for predicting the production of the fractured reservoir when executing the computer program.

[0152] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program, and the computer program implements the method for predicting the production of the fractured reservoir when executed by a processor.

[0153] The embodiment of the present application further provides a computer program product, which comprises a computer program, and the computer program implements the method for predicting the production of the fractured reservoir when executed by a processor.

[0154] In the embodiment of the present application, the scheme for predicting the production of the fractured reservoir can accurately predict the production of the fractured reservoir by taking the wellhead oil, gas, water and sand produced by the oil well in the fractured reservoir as the total output solid-liquid volume, determining the underground conversion volume of the wellhead oil, gas, water and sand produced according to the total output solid-liquid volume, taking the volume of the fracturing fluid and the proppant as the total volume of the earth, determining the total volume of the earth flowback rate based on the fracturing construction parameters, the underground conversion volume or the total output solid-liquid volume and the total volume of the earth, establishing the fracturing reservoir oil well flowback rate and oil pressure cumulative oil fitting prediction graph according to the flowback rate and the oil well data of the production dynamic, determining the oil well production state according to the shape characteristics of the fracturing reservoir oil well flowback rate and oil pressure cumulative oil fitting prediction graph, and determining the cumulative oil production of each oil well in the fractured reservoir according to the oil well production state and the linear segment characteristics of the prediction graph, thereby improving the accuracy of the prediction of the production of the fractured reservoir.

[0155] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can adopt a computer program product embodied 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.

[0156] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 one or more flowcharts and / or blocks

[0157] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 one or more flowcharts and / or blocks

[0158] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 one or more flowcharts and / or blocks

[0159] The above-described specific embodiments, the purpose, technical solutions and advantages of the present application are further described in detail, it should be understood that the above-described is only the specific embodiments of the present application, and is not used to limit the protection scope of the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method of predicting the production of a reservoir undergoing fracturing reformation, characterized in that, The method comprises the following steps: The wellhead oil, gas, water and sand produced by the well of the fractured reservoir are taken as the total solid-liquid volume of the production, and the underground converted volume of the wellhead oil, gas, water and sand produced is determined according to the total solid-liquid volume of the production; The volume of the fracturing fluid and the proppant is taken as the total volume of the fracturing fluid and the proppant into the ground, and the total volume of the fracturing fluid and the proppant into the ground is determined according to the underground converted volume or the total solid-liquid volume of the production and the total volume of the fracturing fluid and the proppant into the ground based on the fracturing construction parameters; A fitting prediction graph of the fracturing well flowback rate and the cumulative oil production of the oil well is established according to the flowback rate and the oil well data of the production performance; The production state of the oil well is determined according to the shape characteristics of the fitting prediction graph of the fracturing well flowback rate and the cumulative oil production of the oil well; The cumulative oil production of each oil well in the fractured reservoir is determined according to the production state of the oil well and the linear segment characteristics of the fitting prediction graph.

2. The method of claim 1, wherein, The cumulative oil production of each oil well in the fractured reservoir is determined according to the production state of the oil well and the linear segment characteristics of the fitting prediction graph, which comprises the following steps: The preferred linear segment characteristics are determined according to the production state of the oil well and the fitting prediction graph of the fracturing well flowback rate and the cumulative oil production of the oil well; The linear equation of the oil pressure linear segment and the cumulative oil production linear segment is established according to the preferred linear segment characteristics; The natural flowback rate limit value when the oil pressure is zero is predicted according to the linear equation of the oil pressure linear segment and the cumulative oil production linear segment; The natural flowback cumulative oil production of each oil well in the fractured reservoir is determined by substituting the natural flowback rate limit value into the linear equation.

3. The method of claim 1, wherein, The production state of the oil well is determined according to the shape characteristics of the fitting prediction graph of the fracturing well flowback rate and the cumulative oil production of the oil well, which comprises the following steps: The pressure characteristics of the fractured well in the later stage when the oil pressure changes within a preset range with the increase of the flowback rate; the linear segment is interrupted in the production process, and a new linear segment with different slope characteristics is presented; the flowback rate and pressure data characteristics when the pressure rises by more than a preset amplitude value with the flowback rate returning; the characteristics of the change of the slope of the linear segment or other pressure fluctuations when the size of the oil nozzle is changed; the characteristics that the flowback rate continues to increase but the oil pressure runs at a low level when the oil pressure is lower than zero and the actual converted formation pressure decreases by more than a preset amplitude value.

4. The method of claim 1, wherein, The total volume of the fracturing fluid and the proppant into the ground is determined according to the underground converted volume or the total solid-liquid volume of the production and the total volume of the fracturing fluid and the proppant into the ground based on the fracturing construction parameters, which comprises the following steps: If the fracturing is one-time fracturing, the total volume of the fracturing fluid and the proppant into the ground is taken as the denominator, and the underground converted volume is taken as the numerator to obtain the total volume of the fracturing fluid and the proppant into the ground flowback rate changing with time; If repeated fracturing occurs, the total volume of the fracturing fluid and the proppant into the ground of at least two times is taken as the denominator, and the total solid-liquid volume of the production is taken as the numerator to determine the total volume of the fracturing fluid and the proppant into the ground flowback rate.

5. The method of claim 1, wherein, The fitting prediction graph of the fracturing well flowback rate and the cumulative oil production of the oil well is established according to the flowback rate and the oil well data of the production performance, which comprises the following steps: The fitting prediction graph is constructed by taking the flowback rate as the horizontal axis.

6. The method of claim 1, wherein, The underground conversion volume of the wellhead oil, gas, water and sand production is determined according to the total solid-liquid volume, including that the underground conversion volume of the produced gas is calculated using a gas state equation combined with a dissolved gas-oil ratio if the underground reservoir is saturated, and the underground conversion volume of the produced gas exists in the form of dissolved gas in the underground and is included in the calculation of the underground oil volume factor if the underground reservoir is not saturated, without additional calculation.

7. The method of claim 1, wherein, The underground conversion volume of the wellhead oil, gas, water and sand production is determined according to the total solid-liquid volume, including that the underground conversion volume of the produced water is calculated using a formation water volume factor.

8. The method of claim 1, wherein, The underground conversion volume of the wellhead oil, gas, water and sand production is determined according to the total solid-liquid volume, including that the underground conversion volume of the produced oil is calculated using an underground oil volume factor.

9. The method of claim 1, wherein, The underground conversion volume of the wellhead oil, gas, water and sand production is determined according to the total solid-liquid volume, including that if the production well produces sand, the underground conversion volume of the sand is converted from the mass and density relationship or the volume and pore volume of the sand.

10. The method of claim 1, wherein, The fracturing operation parameters include one or any combination of the following: sand addition amount, pump speed, pressure, fracturing fluid composition, segment number, cluster number, segment spacing or cluster spacing.

11. The method of claim 1, wherein, Further comprising: The cumulative oil production of all the oil wells in the preset research area of the fracturing reservoir is determined according to the cumulative oil production of each oil well in the fracturing reservoir.

12. An apparatus for fracturing a reservoir production forecast, characterized by, Further comprising: The underground conversion volume determination unit is configured to determine the wellhead oil, gas, water and sand production of the oil well in the fracturing reservoir as the total solid-liquid volume; The underground conversion volume of the wellhead oil, gas, water and sand production is determined according to the total solid-liquid volume; The flowback rate determination unit is configured to determine the total volume of the fracturing fluid and the proppant as the total volume of the fracturing fluid and the proppant into the ground; based on the fracturing operation parameters, the underground conversion volume or the total solid-liquid volume, and the total volume of the fracturing fluid and the proppant into the ground, the flowback rate of the total volume of the fracturing fluid and the proppant into the ground is determined; The chart establishment unit is configured to establish a fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart according to the flowback rate and the oil well data of the production performance; The production state determination unit is configured to determine the production state of the oil well according to the shape characteristics of the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart; The cumulative oil production determination unit is configured to determine the cumulative oil production of each oil well in the fracturing reservoir according to the production state of the oil well and the linear segment characteristics of the prediction chart.

13. The apparatus of claim 12, wherein, The cumulative oil production determination unit is specifically configured to: determine the preferred linear segment characteristics according to the production state of the oil well and the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart; establish a straight line equation of the oil pressure linear segment and the cumulative oil production linear segment according to the preferred linear segment characteristics; predict the natural flowback rate limit value when the oil pressure is zero according to the straight line equation of the oil pressure linear segment and the cumulative oil production linear segment; determine the natural flowback cumulative oil production of each oil well in the fracturing reservoir by substituting the natural flowback rate limit value of the oil well into the straight line equation.

14. The apparatus of claim 12, wherein, The production state determination unit is specifically configured to determine the production state of the oil well according to the following shape characteristics of the fracturing reservoir oil well flowback rate and oil pressure cumulative oil production fitting prediction chart: The pressure characteristics presented in the later stage of fracturing the well when the oil pressure changes with the increase of the flowback rate within a preset range; the straight line segment is interrupted in the production process, and a new straight line segment with different slope is presented; the flowback rate and pressure data characteristics when the pressure rises by more than a preset amplitude value when the flowback rate returns; the characteristics of changing the size of the choke valve to change the slope of the straight line segment or other pressure fluctuations; the characteristics that when the oil pressure is lower than zero, the flowback rate continues to increase, but the oil pressure runs at a low level, and the actual converted formation pressure decreases by more than a preset amplitude value.

15. The apparatus of claim 12, wherein, The flowback rate determination unit is specifically used for: In combination with the fracturing construction condition, if the fracturing is one-time fracturing, the total volume into the ground is taken as the denominator, and the underground converted volume is taken as the numerator to obtain the flowback rate of the total volume into the ground changing with time; If repeated fracturing occurs, the total volume into the ground of at least two times of fracturing is taken as the denominator, and the total output solid-liquid volume is taken as the numerator to determine the flowback rate of the total volume into the ground.

16. The apparatus of claim 12, wherein, The chart establishment unit is specifically used for: constructing the prediction chart with the flowback rate as the horizontal axis.

17. The apparatus of claim 12, wherein, The underground converted volume determination unit is specifically used for: if the underground oil reservoir is saturated, the underground converted volume of the output gas is calculated using the output gas state equation combined with the dissolved gas-oil ratio; if the underground oil reservoir is not saturated, the underground converted volume of the output gas exists in the form of dissolved gas in the underground and is included in the calculation of the crude oil underground volume coefficient, without additional calculation.

18. The apparatus of claim 12, wherein, The underground converted volume determination unit is specifically used for: the underground converted volume of the output water is calculated using the formation water volume coefficient.

19. The apparatus of claim 12, wherein, The underground converted volume determination unit is specifically used for: the underground converted volume of the output oil is calculated using the underground crude oil volume coefficient.

20. The apparatus of claim 12, wherein, The underground converted volume determination unit is specifically used for: if the sand production well produces sand, the underground converted volume of the sand production is converted from the relationship between the mass and the density of the sand production or from the volume and the pore volume of the sand production.

21. The apparatus of claim 12, wherein, The fracturing construction parameters include one or any combination of the sand amount, the pump speed, the pressure, the fracturing fluid composition, the segment number, the cluster number, the segment spacing, or the cluster spacing.

22. The apparatus of claim 12, wherein, Further comprising an overall condition determination unit for determining the cumulative oil production of all oil wells in the preset research area of the fracturing and reconstruction oil reservoir according to the cumulative oil production of each oil well in the fracturing and reconstruction oil reservoir.

23. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the computer program comprises the steps of: The processor executes the computer program to realize the method of any one of claims 1 to 11.

24. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the method of any one of claims 1 to 11.

25. A computer program product, characterised in that, The computer program product comprises a computer program, and the computer program is executed by the processor to realize the method of any one of claims 1 to 11.

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