Shale oil well variable pressure and variable production testing methods and well test data analysis methods

Abstract

This invention discloses a method for testing shale oil wells with varying pressure and production rates, and a method for analyzing the test data. The testing method includes: after a first set shut-in time, measuring the pressure at each measuring point in the wellbore from top to bottom to obtain first static pressure gradient data; during production using a nozzle device of a set specification, measuring oil production, water production, wellhead oil pressure, casing pressure, and the pressure at the first target measuring point at second set intervals to obtain continuous variable pressure test data; and sequentially changing nozzle devices of different specifications according to set rules, measuring oil production, water production, wellhead oil pressure, and casing pressure at third set intervals during production using each nozzle device to obtain continuous variable flow rate test data. This method, through variable production and variable pressure coupled well testing, accurately obtains data such as static pressure at the target measuring point and production under different operating conditions, even in shale oil wells with low permeability, low oil production, and long formation pressure recovery time.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to a method for testing shale oil wells with varying pressure and production rates, and a method for analyzing test data. Background Technology

[0002] Shale oil has extremely low permeability, often less than 0.1 md, and a complex and variable pore structure, with the main flow pores ranging in diameter from approximately 4 to 200 nm. Well testing is conducted to obtain important characteristics of its reservoir parameters.

[0003] Currently, there are four main well testing methods for oil wells: ① Single-point well testing: This method measures the stable pressure under only one operating condition, i.e., the stable pressure obtained during a fixed production stage. ② System well testing: This method involves stabilizing production at a small output, measuring the corresponding stable bottom hole flowing pressure, then increasing the output and measuring the bottom hole flowing pressure again. This process is repeated for 4-5 operating conditions to obtain production and pressure data under each operating condition. ③ Isochronous well testing: This method is an optimization of conventional backpressure well testing, involving equal time intervals at several different production levels and observing the corresponding pressure changes. ④ (Modified) isochronous well testing: This optimized method is based on isochronous well testing to shorten testing time and save costs. It requires continuous production for the same duration for 3-4 consecutive stable production levels. The difference is that in modified isochronous well testing, the shut-in time and well opening time are the same each time. Summary of the Invention

[0004] The inventors discovered that existing well testing methods for oil wells often require maintaining the same production rate for a certain period of time, which is difficult to achieve for shale oil wells. At the same time, well testing of shale oil wells also faces challenges such as small test oil volume, large oil-casing pressure difference, and large water production during the testing process.

[0005] In order to at least partially solve the technical problems existing in the prior art, the inventors made this invention, which provides a method for testing shale oil wells with variable pressure and variable production and a method for analyzing test data through specific implementation methods. Based on seepage theory, a coupled test method for variable production and variable pressure is established. This method can obtain data such as static pressure at the target measuring point and production under different working conditions when the permeability of shale oil wells is low, the oil production is low, and the formation pressure recovery time is long. This prepares for subsequent reservoir and fracture parameter inversion and production capacity equation determination.

[0006] In a first aspect, embodiments of the present invention provide a method for testing shale oil wells with varying pressure and production rates, including:

[0007] The procedure for shutting in a shale oil well is as follows: After the first set time has elapsed since shutting in the well, the pressure at each measuring point in the wellbore is measured sequentially from top to bottom to obtain the first static pressure gradient data.

[0008] The variable pressure continuous test procedure involves measuring the oil production, water production, wellhead oil pressure, casing pressure, and pressure at the first target measuring point at second set intervals within a second set time period during the production process using a nozzle device of set specifications, thereby obtaining variable pressure continuous test data.

[0009] The variable flow rate continuous test procedure involves sequentially changing different specifications of nozzle devices according to set rules. During the production process using each nozzle device, the oil production, water production, wellhead oil pressure, and casing pressure are measured at third set intervals within a third set time period to obtain variable flow rate continuous test data.

[0010] Secondly, embodiments of the present invention provide a method for analyzing well test data of shale oil wells with varying pressure and production rates, including:

[0011] The above-mentioned variable pressure and variable production well test method was used to obtain the well test data of shale oil wells;

[0012] The static pressure at the first target measuring point is obtained based on the variable pressure continuous test data in the well test data.

[0013] The static pressure at the target location in the wellbore is determined based on the static pressure at the first target measuring point and the first static pressure gradient data in the well test data.

[0014] Production capacity analysis is performed based on the variable flow rate continuous test data from the well test data.

[0015] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0016] (1) Existing well testing technologies often require strictly maintaining the production rate at a certain value. However, shale oil reservoirs have low porosity and permeability, low oil production, large oil-casing pressure difference, large water production, and a long time to recover pressure to a stable value. Therefore, it is difficult to guarantee that the production rate can be maintained at a certain value for a certain period of time. The shale oil well variable pressure and variable production well testing method provided in this embodiment includes a static pressure gradient test step and a variable pressure and variable production coupling of variable pressure continuous test and variable flow continuous test. The production rate is controlled by the specifications of the nozzle device. Based on the seepage theory, the variable production and variable pressure coupling test method can accurately obtain data such as static pressure and production under different working conditions at the target measuring point when the permeability and oil production of shale oil well are low. This prepares for subsequent reservoir and fracture parameter inversion and production capacity equation determination.

[0017] (2) The shale oil well variable pressure and variable production well test method provided in the embodiments of the present invention clearly defines the test and construction requirements, is highly operable, and conforms to the actual situation of shale oil field.

[0018] (3) The shale oil well variable pressure and variable production well test method provided in this embodiment of the invention combines pressure drop and pressure recovery unstable well test to obtain shut-in recovery pressure data and second static pressure gradient data. By comparing the static pressure interpreted by different well test methods, the accuracy and reliability of well test interpretation results are improved, and the problem of unstable and inaccurate measured static pressure data caused by the long formation pressure recovery time of shale oil reservoirs is overcome.

[0019] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 This is a flowchart of the variable pressure and variable production well test method for shale oil wells in Embodiment 1 of the present invention;

[0023] Figure 2 This is a test pressure curve diagram for each test stage in Embodiment 2 of the present invention. Detailed Implementation

[0024] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] This invention provides a method for testing shale oil wells with variable pressure and variable production, and a method for analyzing test data. By using a coupled test with variable production and variable pressure, the method can accurately obtain data such as static pressure at the target measuring point and production under different operating conditions when the shale oil well has low permeability, low oil production, and long formation pressure recovery time.

[0028] Example 1

[0029] Embodiment 1 of the present invention provides a method for testing shale oil wells with varying pressure and production rates, the process of which is as follows: Figure 1 As shown, it includes the following steps:

[0030] Step S11: Well shut-in static pressure gradient test step. After shutting in the shale oil well for the first set time, the pressure at each measuring point in the wellbore is measured sequentially from top to bottom to obtain the first static pressure gradient data.

[0031] The initial timeframe is typically 3 days, but the specific time can be flexibly set according to the on-site construction conditions.

[0032] The rule for determining measuring points in the wellbore is usually as follows: in the well section above 100m of the oil layer, one measuring point is designed every 500 to 1000m, and the density is gradually increased below that, with one measuring point designed every 20 to 100m after entering the oil layer section.

[0033] The above rules apply to vertical wells and horizontal wells that use cable-guided pressure gauges to measure pressure; for storage pressure gauges, since the wire cannot be lowered into the horizontal section, the measuring point cannot be set on the well section where the inclination is greater than the set inclination threshold.

[0034] After obtaining the pressure (static pressure) at each measuring point, the static pressure gradient data of the well section between the two measuring points can be obtained through the pressure at the previous measuring point. Based on the first static pressure gradient data obtained in real time, it is determined whether there is fluid accumulation. If so, the pressure measuring instrument is raised into the blowout preventer to drain the fluid, and the pressure measuring instrument is lowered into the measuring point before the drainage to continue the measurement.

[0035] In some embodiments, prior to the shut-in static pressure gradient test step, there are also steps for backflowing accumulated fluid and a safety test step.

[0036] The safety testing procedures include connecting the blowout preventer and the top seal, and performing pressure tests on the blowout preventer, the connection between the blowout preventer and the Christmas tree, and the top seal to ensure the safety of subsequent well testing.

[0037] Step S12: Variable pressure continuous test step. During the production process, the oil production, water production, wellhead oil pressure, casing pressure and pressure at the first target measuring point are measured at second set intervals within a second set time period to obtain variable pressure continuous test data.

[0038] If the pressure measuring instrument is not raised during the static pressure gradient test, the oil test can begin directly after the static pressure gradient test step, with the current measuring point as the first target measuring point, or the position of the pressure measuring instrument can be adjusted to the first target measuring point before starting the oil test.

[0039] The second set time can be around 60 days, which can be flexibly set according to the on-site construction conditions. The second set interval can be 1 hour. Continuous flow pressure and flow temperature are measured at the first target measuring point, while oil production, liquid production, water production, and sand content are continuously measured. During the test, oil pressure and casing pressure are continuously measured, and one point is recorded every hour.

[0040] Step S13: Variable flow rate continuous test step. According to the set rules, different specifications of oil nozzle devices are changed in sequence. During the production process using each oil nozzle device, the oil production, water production, wellhead oil pressure and casing pressure are measured at the third set interval within the third set time period to obtain variable flow rate continuous test data.

[0041] If the nozzle device setting in the variable pressure continuous test step is of a higher specification, i.e., with a larger flow rate, then starting from the next specification of this rule, the nozzle device specification changes from large to small; if the nozzle device setting in the variable pressure continuous test step is of a lower specification, i.e. with a smaller flow rate, then starting from the next specification of this rule, the nozzle device specification changes from small to large.

[0042] The third setting time is usually around 1 day. The third setting interval can be the same as or different from the second setting interval.

[0043] If the shale oil well is a horizontal well, both the first and second target measuring points must meet the following conditions:

[0044] Located on a well section with an inclination within a set inclination threshold, the distance between it and a well section where the inclination begins to exceed the set inclination threshold is less than the set distance threshold.

[0045] The locations of the first and second target measuring points can be the same or different. By combining the pressure test data from the first and / or second target measuring points with the static pressure gradient data, the static pressure at any point in the wellbore can be obtained.

[0046] Furthermore, the pressure at the measuring point, the first target measuring point, and the second target measuring point can be measured using a direct-reading pressure gauge; alternatively, the pressure at the measuring point, the first target measuring point, and the second target measuring point can be measured using a direct-reading pressure gauge and two storage pressure gauges connected in series. The measurement results of the storage pressure gauges are used to verify the measurement results of the direct-reading pressure gauges. The two storage pressure gauges connected in series are used to avoid the risk of damage to a single storage pressure gauge.

[0047] The first static pressure gradient data, variable pressure continuous test data, and variable flow continuous test data obtained through the above steps constitute the variable pressure and variable production well test data for shale oil wells.

[0048] Existing well testing technologies often require strictly maintaining production at a certain value. However, shale oil reservoirs are characterized by low porosity and permeability, low oil production, large pressure differential between oil and casing, large water production, and a long time for pressure to recover to stability. Therefore, it is difficult to guarantee that production will be maintained at a certain value for a certain period of time. The variable pressure and variable production well testing method for shale oil wells provided in Embodiment 1 of this invention includes a static pressure gradient testing step and a variable pressure and variable production coupling of variable pressure continuous testing and variable flow continuous testing. Production is controlled by the specifications of the nozzle device. Based on seepage theory, the variable production and variable pressure coupling testing method can accurately obtain data such as static pressure and production under different working conditions at the target measuring point when the permeability and oil production of shale oil wells are low. This prepares for subsequent reservoir and fracture parameter inversion and production capacity equation determination.

[0049] The variable pressure and variable production well test method for shale oil wells provided in Embodiment 1 of the present invention clearly defines the testing and construction requirements, is highly operable, and conforms to the actual situation in shale oil fields.

[0050] In some optional embodiments, after the variable flow rate continuous test step, a well shut-in formation pressure test step may also be included. During the formation pressure recovery process of well shut-in, the pressure at the second target measuring point is measured at a fourth set interval until the measured pressure change is less than the set range, and well shut-in recovery pressure data is obtained.

[0051] In some optional embodiments, the well shut-in formation pressure test step may further include measuring the pressure at each measuring point in the wellbore from bottom to top, starting from the second target measuring point, to obtain the second static pressure gradient data.

[0052] The second static pressure gradient data is used to verify the first static pressure gradient data; the static pressure data of the measuring points obtained from the shut-in recovery pressure data is used to verify the static pressure data of the measuring points obtained from the variable pressure continuous test data.

[0053] The variable pressure and variable production well test method for shale oil wells provided in Embodiment 1 of the present invention combines pressure drop and pressure recovery unstable well tests to obtain shut-in recovery pressure data and second static pressure gradient data. By comparing the static pressure interpreted by different well test methods, the accuracy and reliability of well test interpretation results are improved, and the problem of unstable and inaccurate measured static pressure data caused by the long formation pressure recovery time of shale oil reservoirs is overcome.

[0054] Example 2

[0055] Embodiment 2 of the present invention provides a specific application of a shale oil well variable pressure and variable production well test method.

[0056] (1) Well test equipment and data acquisition requirements

[0057] The equipment involved in the testing process is listed in the Equipment Required for Construction List, as shown in Table 1. Special attention should be paid to the high accuracy requirements of the pressure gauges used in the pressure test; please refer to the Parameter Requirements List for High-Precision Storage Electronic Pressure Gauges, as shown in Table 2. All data must be collected accurately and completely; please refer to the Well Test Data Acquisition Requirements List, as shown in Table 3. Specific equipment and parameter lists may be adjusted based on actual conditions.

[0058] Table 1. Equipment Required for Construction

[0059] name Models and specifications quantity Remark cable car - 1 unit test Wellhead blowout preventer - 1 set test Storage electronic pressure gauge 60MPa 2 stress test Direct-reading electronic pressure gauge 60MPa 1 stress test Weight bar 100kg 1 stress test Double-row cart - 1 unit Production Support crane - 1 unit Production Support

[0060] Table 2 Parameter Requirements for High-Precision Storage Electronic Pressure Gauges

[0061]

[0062] Table 3 Requirements for Well Test Data Acquisition

[0063]

[0064] (2) Well test implementation requirements

[0065] 1) Drain the accumulated fluid until the bottom of the well and the wellbore are clear and there is no more fluid at the bottom of the well (estimated to take 20 days).

[0066] 2) One direct-reading pressure gauge and two storage pressure gauges were connected in series and lowered into the well for testing. Static pressure was maintained for 3 days (72 hours), and the static pressure gradient was measured.

[0067] 3) The entire continuous flow test was conducted by setting one direct-reading pressure gauge and two storage pressure gauges in series in the well.

[0068] 4) This test adopted the continuous bottom hole pressure method, and the oil production and water production were continuously measured during the pressure test.

[0069] 5) After the continuous pressure and temperature tests are completed, shut in the well to test the pressure recovery data. It is required to continuously test the pressure in the middle of the oil layer for more than one month.

[0070] 6) The measured static pressure gradient in the wellbore shall be carried out as required.

[0071] 7) Oil sample composition testing requires sampling at least twice at the end of the production period for oil sample composition analysis.

[0072] 8) For water-producing oil wells, water samples should be taken three times during the production period for water quality analysis.

[0073] 9) During the well test, daily records of oil production, oil pressure, casing pressure, wellhead temperature, separator temperature and pressure, etc. should be kept, and parameters such as water cut and oil-water ratio should be analyzed based on sampling and testing.

[0074] 10) Throughout the entire construction process, the sand production status must be strictly monitored, the production pressure differential must be controlled, and sand production from the formation must be prevented.

[0075] 11) Follow the "Specifications for Recording Oil Testing Data" (SY / T 6013-2019) to ensure that all data are collected accurately and completely.

[0076] 12) Test-related parameters can be scientifically and reasonably adjusted based on the actual dynamic response of the oil well.

[0077] The specific testing process is as follows:

[0078] Step 1: Preparation before testing

[0079] The accumulated fluid is drained back until the bottom of the well and the wellbore are clear and there is no more fluid at the bottom of the well, at which point testing can begin.

[0080] Pressure testing after connecting the blowout preventer: After connecting the blowout preventer and the top seal, pressure test the blowout preventer, the connection between the blowout preventer and the Christmas tree, and the top seal to ensure construction safety.

[0081] Step 2: Well Static Pressure Gradient Test

[0082] After shutting in the well for approximately 3 days, one direct-reading pressure gauge and two tandem storage pressure gauges are lowered to test the static pressure gradient. Stopping depths are 0m, 500m, 1000m, 1500m, 2000m, 2290m, 2296m, and 2300m (this stopping depth design is just an example; the specific design should be flexibly set according to on-site construction and measurement schedule requirements). The pressure gauges are held at each measuring point for at least 15 minutes to ensure stable pressure and temperature values. Based on the analysis of the direct-reading test data, it is determined whether there is fluid accumulation in the wellbore. If fluid is present, it must be drained. The instrument is then raised to the blowout preventer, drained, and then lowered back in to begin continuous testing.

[0083] Step 3: Open the well and conduct continuous testing.

[0084] Before the oil test, one direct-reading and two storage-type electronic pressure gauges are lowered into the system. During lowering, the flow pressure gradient is measured at various depths: 0m, 500m, 1000m, 1500m, 2000m, 2290m, 2296m, and 2300m. Each measurement point is paused for 10 minutes. Finally, continuous oil testing is conducted at the 2300m depth. If the instrument is not raised after the static pressure test, oil testing begins directly. The pressure gauges are continuously used at the 2300m depth to measure continuous flow pressure and temperature, as well as continuous oil and water production. During the test, oil production, water volume, oil pressure, and casing pressure are continuously measured (one point is recorded every hour). Oil production is controlled by the nozzle size (6mm), and the test duration is approximately 60 days.

[0085] Step 4: Conduct capacity testing

[0086] After continuous testing, a production sequence similar to backpressure testing is adopted, with production increasing in an incremental manner, and multiple operating regimes are tested (the specific regime is determined according to the production capacity of a single well). Each operating regime test reaches stability in about one day, and the test continuously measures oil production, water production, oil pressure, and casing pressure (one point is recorded every hour).

[0087] Step 5: Well shut-in test formation pressure

[0088] After continuous testing, the designed pressure recovery time is approximately 45 days. If the wellhead pressure remains stable for more than 10 days, the shut-in time can be shortened (the shut-in test time is dynamically adjusted based on the direct-read test data). An unstable pressure recovery test is then conducted after shutting in the well. The recovery test process is monitored, and the direct-read pressure data is analyzed daily. The test ends once the pressure stabilizes and no longer changes.

[0089] Step 6: Measure the static pressure gradient

[0090] Raise the testing instrument, measuring the static pressure gradient at each stop point during the raising process. The depth of each stop point should match the depth of the static pressure gradient test in the wellbore. Stop point depths are: 2296m, 2000m, 1500m, 1000m, 500m, and 0m. Each stop should last 10-15 minutes. Remove the instrument and review the test data. After the test is completed, resume normal production.

[0091] See Figure 2 The figure shows the pressure curves for all test stages, where 1 represents the continuous test stage (the result of the third test), 2 represents the production capacity test stage (the result of the fourth test), and 3 represents the shut-in test stage (the result of the fifth and sixth test).

[0092] The time periods and time intervals set in Embodiments 1 and 2 of this invention are just examples. In practice, they can be flexibly set according to the on-site construction conditions.

[0093] Based on the inventive concept of this invention, embodiments of this invention also provide a method for analyzing shale oil well test data with varying pressure and production rates, including:

[0094] The above-mentioned variable pressure and variable production well test method was used to obtain the well test data of shale oil wells;

[0095] The static pressure at the first target measuring point is obtained based on the variable pressure continuous test data in the well test data.

[0096] The static pressure at the target location in the wellbore is determined based on the static pressure at the first target measuring point and the first static pressure gradient data in the well test data.

[0097] Production capacity analysis is performed based on the variable flow rate continuous test data from the well test data.

[0098] In some embodiments, it may further include:

[0099] The static pressure at the second target measuring point is obtained based on the shut-in recovery pressure data in the well test data; the static pressure at the target location in the wellbore is determined based on the static pressure at the second target measuring point and the first static pressure gradient data in the well test data; the static pressure at the target location is determined by combining the static pressure at the target location determined by the static pressure at the first target measuring point and the static pressure at the second target measuring point.

[0100] The static pressure at the second target measuring point is obtained based on the shut-in recovery pressure data in the well test data; the static pressure at the target location in the wellbore is determined based on the static pressure at the second target measuring point and the second static pressure gradient data in the well test data; the static pressure at the target location is determined by combining the static pressure at the target location determined by the static pressure at the first target measuring point and the static pressure at the second target measuring point.

[0101] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0102] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0103] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term “comprising” as used in the specification or claims is interpreted in a manner similar to the term “including,” as it is understood when used as a conjunction in the claims. Additionally, the use of any term “or” in the specification of the claims is intended to mean “non-exclusive or.” The terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

Claims

1. A method for testing shale oil wells with varying pressure and production rates, characterized in that, include: Well shut-in static pressure gradient test procedure: After shutting in the shale oil well for the first set time, measure the pressure at each measuring point in the wellbore from top to bottom to obtain the first static pressure gradient data; Variable pressure continuous test steps: During the production process using a nozzle device of set specifications, the oil production, water production, wellhead oil pressure, casing pressure, and pressure at the first target measuring point are measured at the first set interval time within the second set time period to obtain variable pressure continuous test data. Variable flow rate continuous test steps: Change the oil nozzle device of different specifications in sequence according to the set rules. During the production process using each oil nozzle device, measure the oil production, water production, wellhead oil pressure and casing pressure at the second set interval within the third set time period to obtain the variable flow rate continuous test data. Well shut-in formation pressure test procedure: During the formation pressure recovery process during well shut-in, the pressure at the second target measuring point is measured at the third set interval until the measured pressure change is less than the set range, and the well shut-in recovery pressure data is obtained; Starting from the second target measuring point, the pressure at each measuring point in the wellbore is measured sequentially from bottom to top to obtain the second static pressure gradient data.

2. The method as described in claim 1, characterized in that, Also includes: The pressure at the measuring point, the first target measuring point, and the second target measuring point is measured by using a direct-reading pressure gauge and two series-connected storage pressure gauges to obtain the first static pressure gradient data or the second static pressure gradient data.

3. The method as described in claim 1, characterized in that, If the shale oil well is a horizontal well, both the first target measuring point and the second target measuring point satisfy the following conditions: The distance between a well section located on a well section with an inclination within a set inclination threshold and a well section where the inclination begins to exceed the set inclination threshold is less than a set distance threshold.

4. The method as described in claim 1, characterized in that, The rules for determining the measuring points in the wellbore where the first or second static pressure gradient data is obtained are as follows: In the oil-bearing section above 100m, a measuring point is designed every 500-1000m, and the density is gradually increased below that, with a measuring point designed every 20-100m after entering the oil-bearing section.

5. The method as described in claim 1, characterized in that, The shut-in static pressure gradient test procedure also includes: Based on the real-time first static pressure gradient data, determine whether it is necessary to drain the accumulated fluid. If so, the accumulated fluid will be drained.

6. A method for analyzing well test data of shale oil wells with varying pressure and production rates, characterized in that, include: Well test data of shale oil wells are obtained by the method described in any one of claims 1 to 5; The static pressure at the first target measuring point is obtained based on the variable pressure continuous test data in the well test data. The static pressure at the target location in the wellbore is determined based on the static pressure at the first target measuring point and the first static pressure gradient data in the well test data. Production capacity analysis is performed based on the variable flow rate continuous test data from the well test data.

7. The method as described in claim 6, characterized in that, Also includes: The static pressure at the second target measuring point is obtained based on the shut-in recovery pressure data in the well test data. The static pressure at the target location in the wellbore is determined based on the static pressure at the second target measuring point and the first static pressure gradient data in the well test data. The static pressure at the target location is determined by combining the static pressure determined by the static pressure at the first target measuring point and the static pressure determined by the static pressure at the second target measuring point.

8. The method as described in claim 6, characterized in that, Also includes: The static pressure at the second target measuring point is obtained based on the shut-in recovery pressure data in the well test data. The static pressure at the target location in the wellbore is determined based on the static pressure at the second target measuring point and the second static pressure gradient data in the well test data. The static pressure at the target location is determined by combining the static pressure determined by the static pressure at the first target measuring point and the static pressure determined by the static pressure at the second target measuring point.

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