Method for predicting long time of pressure boosting and yield increasing of shale gas well, computer device and medium

Abstract

This invention provides a method, computer equipment, and medium for predicting the production increase duration of shale gas well pressurization. The method includes: S1, calculating the unit pressure drop production under different wellhead pressures before pressure transmission; S2, fitting the unit pressure drop production obtained in step S1 to obtain a relationship between the wellhead pressure and the unit pressure drop production; S3, calculating the unit pressure drop production when the wellhead pressure is reduced to a certain level based on the relationship obtained in step S2; S4, determining the cumulative production increase after pressurization based on the unit pressure drop production calculated in step S3; and calculating the production increase duration after pressurization. The equipment includes at least one processor; a memory storing program instructions, including instructions to execute the above method; and the storage medium storing the program instructions. The parameters used in this invention for predicting production increase duration are easily obtainable, have universality, and the prediction results are accurate with small errors.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development and application, specifically to a method, computer equipment, and medium for predicting the production increase time of shale gas well pressurization. Background Technology

[0002] In the mid-to-late stages of shale gas field production, the wellhead pressure drops to the pipeline transmission pressure, significantly reducing the well's ability to carry liquid and increasing the probability of water flooding, severely hindering stable production. In current gas production projects, pressurization plays a crucial role in stabilizing and increasing gas field production. However, shale gas pressurization differs from conventional gas reservoir pressurization. Shale gas production declines more rapidly, and new wells typically require pressurization after one year of operation. After a period of pressurization on the platform, the rapid decrease in gas volume causes the pressurizer unit load to drop below 50%, failing to fully utilize the unit's capacity and resulting in wasted load. Therefore, quickly evaluating the production increase duration after pressurization is crucial for the rational allocation, relocation, and reuse of pressurizer units.

[0003] Currently, the prediction of the production increase duration after pressurization mainly relies on two methods: summarizing patterns from data of existing pressurized wells in the gas field and numerical simulation. However, because the production conditions of individual shale gas wells vary, the accuracy of the pressurization duration obtained by the empirical method (i.e., summarizing patterns) is low, and it cannot support the duration prediction for wells in new development areas. Most gas wells use numerical simulation to predict the stable production duration after pressurization, but the accuracy of the numerical simulation results depends on the precision of the parameter values. The storage and migration characteristics of shale gas are complex, making it difficult to obtain accurate geological, engineering, and production data. This results in significant uncertainty in the parameters required for numerical simulation, making it difficult to develop a universally applicable prediction method. Summary of the Invention

[0004] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. For example, one objective of this invention is to provide a method for predicting the duration of increased production in shale gas well pressurization and extraction with accurate and universally applicable prediction results.

[0005] To achieve the above objectives, the present invention provides a method for predicting the production increase time of shale gas well pressurization.

[0006] The method includes the following steps: S1, calculating the unit pressure drop production under different wellhead pressures before pressure transmission; S2, fitting the unit pressure drop production under different wellhead pressures calculated in step S1 to obtain the relationship between the single wellhead pressure and the unit pressure drop production; S3, calculating the unit pressure drop production when the wellhead pressure is reduced by a certain pressure according to the relationship obtained in step S2; S4, determining the cumulative production increase after pressure boosting according to the unit pressure drop production calculated in step S3; S5, calculating the production increase duration after pressure boosting using the following formula: △t is the pressurization duration, in seconds; △Q is the cumulative increase in output after pressurization, in ten. 4 m 3 △q represents the preset increase in daily gas production after pressurization, 10 4 m 3 / d.

[0007] Alternatively, in step S1, the unit pressure drop output can be calculated using the following formula:

[0008]

[0009] Among them, Q t For the cumulative production at time t, 10 4 m 3 ;△P t P is the wellhead production pressure differential at time t, in MPa; max P represents the peak wellhead pressure, in MPa. t Let t be the wellhead pressure at time t, in MPa.

[0010] Alternatively, in step S2, the fitting may include fitting using a binomial.

[0011] Alternatively, in step S2, the relation is:

[0012]

[0013] in, Let t be the wellhead unit pressure drop production at time t, 10 4 m 3 / MPa; P t Let t be the wellhead pressure at time t, in MPa.

[0014] Alternatively, a, b, and c can be determined by fitting and are dimensionless.

[0015] Optionally, step S2 may further include: obtaining the relationship curve between single-wellhead pressure and unit pressure drop production through the fitting.

[0016] Alternatively, in step S3, the certain pressure is determined based on the intake pressure, exhaust pressure, intake temperature, processing volume, and power of the compressor selected for boosting.

[0017] Optionally, step S4 includes: calculating the decrease in wellhead pressure after pressurization, and then multiplying the decrease by the unit pressure drop production calculated in step S3 to obtain the cumulative increase in production after pressurization.

[0018] In another aspect, the present invention provides a computer device.

[0019] The device includes: at least one processor; and a memory storing program instructions, wherein the program instructions are configured to be executed by the at least one processor, the program instructions including instructions for performing the method as described above.

[0020] In another aspect, the present invention provides a computer-readable storage medium.

[0021] The computer-readable storage medium stores computer program instructions that, when executed by a processor, implement the method described above.

[0022] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0023] (1) This invention utilizes the relationship between wellhead pressure and cumulative gas production to calculate the change law of wellhead unit pressure drop production. By changing the wellhead pressure, the corresponding unit pressure drop production after the pressure is reduced is obtained. The calculation process is simple and the calculation results are accurate. Among them, the average relative error between the calculated unit pressure drop production of existing boosted gas wells and the actual unit pressure drop production is 2.1%, and the average relative error between the calculated production increase time and the actual production increase time is 5.5%, and the prediction results are accurate.

[0024] (2) This invention solves the problem that there is currently no mature method for predicting the duration of shale gas pressurization and production. The parameters used are the cumulative gas production of the gas well, the daily gas production, the wellhead pressure, etc., which do not involve the characteristic parameters of the gas well. The parameters are easy to obtain and have universality. Attached Figure Description

[0025] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0026] Figure 1 This illustrates a schematic diagram of the fitting relationship curves between production per unit pressure drop and wellhead pressure for different single wells in Exemplary Example 2.

[0027] Figure 2 A schematic diagram of the daily gas production change after pressurization in Exemplary Example 2 is shown.

[0028] Figure 3 A schematic diagram of the fitting curve of wellhead unit pressure drop production versus wellhead pressure in Example 1 is shown. Detailed Implementation

[0029] The following description, in conjunction with exemplary embodiments, details the method for predicting the production increase duration of shale gas well boosting and extraction according to the present invention, as well as the computer equipment and media.

[0030] Exemplary Example 1

[0031] This exemplary embodiment provides a method for predicting the production increase time of shale gas well pressurization.

[0032] The method may include the following steps:

[0033] S1. Calculate the unit pressure drop production under different wellhead pressures before the pressure is reduced to the level before the pressure is transmitted.

[0034] In this embodiment, the unit pressure drop production under different wellhead pressures before transmission can be calculated using the following formula based on wellhead pressure data under different cumulative production conditions of a single well:

[0035]

[0036] Among them, Q t For the cumulative production at time t, 10 4 m 3 ;△P t P is the wellhead production pressure differential at time t, in MPa; max P represents the peak wellhead pressure, in MPa. t Let t be the wellhead pressure at time t, in MPa.

[0037] S2. The unit pressure drop production calculated in step S1 under different wellhead pressures is fitted using a binomial formula to obtain the relationship between single wellhead pressure and unit pressure drop production.

[0038] In this embodiment, step S2 further includes: obtaining the relationship curve between single wellhead pressure and unit pressure drop production by fitting.

[0039] In step S2, the fitted relation is:

[0040]

[0041] in, Let t be the wellhead unit pressure drop production at time t, 10 4 m 3 / MPa; P t Let be the wellhead pressure at time t, in MPa; where a, b, and c can be determined by fitting and are dimensionless.

[0042] S3. Based on the relationship obtained in step S2, calculate the unit pressure drop production when the wellhead pressure is reduced by a certain pressure.

[0043] In this embodiment, the certain pressure is a fixed value, which can be determined according to the compressor model and the intake air volume.

[0044] S4. Based on the unit pressure drop output calculated in step S3, determine the cumulative increase in output after pressure boosting.

[0045] In this embodiment, step S4 may specifically include: calculating the reduction in wellhead pressure after pressurization, and then multiplying the reduction value by the unit pressure drop production calculated in step S3 to obtain the cumulative increase in production after pressurization.

[0046] In this embodiment, the reduction in wellhead pressure after pressurization can be obtained by subtracting the wellhead pressure values ​​before and after pressurization.

[0047] S5. Calculate the production increase time after boosting.

[0048] In this embodiment, the following formula is used for calculation:

[0049]

[0050] △t is the pressurization duration, in seconds; △Q is the cumulative increase in output after pressurization, in ten. 4 m 3 △q represents the preset increase in daily gas production after pressurization, 10 4 m 3 / d.

[0051] Exemplary Example 2

[0052] This exemplary embodiment provides a method for predicting the production increase duration of shale gas wells after pressurization. The invention does not require complex models; it uses pre-existing wellhead pressure data to fit a curve showing the change in production per unit pressure drop of a single well, predicts the production per unit pressure drop after the wellhead pressure is reduced, calculates the cumulative increase in gas production after pressurization, and then uses relevant relationships to calculate the production increase duration after pressurization. The calculation method is simple, requires few parameters, and is applicable to most normally producing shale gas wells, thus having a wide range of applications.

[0053] Specifically, the method includes the following steps:

[0054] A method for predicting the production enhancement time of shale gas well pressurization, characterized by the following steps:

[0055] (1) Based on the wellhead pressure data under different cumulative production conditions of a single well, the unit pressure drop production under different wellhead pressures before pressure transmission is calculated using the following formula:

[0056]

[0057] In the formula, Q t For the cumulative production at time t, 10 4 m 3 ;ΔP t P is the wellhead production pressure differential at time t, in MPa; max Peak wellhead pressure, MPa, P t Let t be the wellhead pressure at time t, in MPa.

[0058] (2) The calculated unit pressure drop production under different wellhead pressures was fitted using a binomial formula, resulting in the following: Figure 1 The curve showing the relationship between single-wellhead pressure and unit pressure drop production, along with related formulas, is as follows:

[0059]

[0060] In the formula, Let t be the wellhead unit pressure drop production at time t, 10 4 m 3 / MPa; P t Let be the wellhead pressure at time t, in MPa, and a, b, and c be the fitted parameters, which are dimensionless.

[0061] like Figure 1 As shown, this invention fits the relationship curves and related formulas for two wells, and then in the next step, the unit pressure drop production under other wellhead pressures can be calculated.

[0062] (3) Calculate the unit pressure drop production when the wellhead pressure decreases by ΔP′ based on the relationship obtained in step (2). ΔP′ is a known parameter that is related to the intake and exhaust pressures, intake temperature, gas processing capacity, and power parameters of the compressor selected for boosting.

[0063] (4) The cumulative increase in output ΔQ after pressurization can be obtained from the unit pressure drop output calculated in step (3).

[0064] (5) Assume that the gas well is pressurized at time t1, and the daily gas production of a single well increases from q to q' within 1-2 days, with an increase of Δq. By time t2, the daily gas production of a single well decreases back to the level before pressurization.

[0065] (6) The daily gas production after pressurization is considered to decrease linearly. The cumulative gas production ΔQ after pressurization is the area of ​​a triangle, which can be found in [reference]. Figure 2 The time Δt for increased production after pressurization can be calculated using the triangle area formula:

[0066]

[0067] ΔQ is obtained from step (4), 10 4 m 3 Δt is the pressurization duration, in days; Δq is the increase in daily gas production after pressurization, in ten. 4 m 3 / d.

[0068] To better understand the exemplary embodiments described above, further explanation is provided below with reference to specific examples.

[0069] Example 1

[0070] This example predicts the production increase time after pressurization of a gas well in the Changning shale gas field, including the following steps:

[0071] 1. The required calculation parameters for this well are shown in Table 1 below:

[0072] Table 1 Parameters required for calculation

[0073] Parameter name numerical values Peak wellhead pressure (MPa) 34.22 Wellhead pressure (MPa) at a cumulative production of 7.41 million cubic meters 26.15 Wellhead pressure (MPa) at a cumulative production of 15.86 million cubic meters 19.19 Wellhead pressure (MPa) at a cumulative production of 32.12 million cubic meters 13.32 Wellhead pressure (MPa) at a cumulative production of 57.71 million cubic meters 7.23 Wellhead pressure before pressurization (MPa) 5.27 Wellhead pressure after pressurization (MPa) 4.78 <![CDATA[Daily gas production before pressurization (10 4 m 3 )]]> 4.5 <![CDATA[Daily gas production after pressurization (10 4 m 3 )]]> 6.1

[0074] 2. Based on the wellhead pressure data under different cumulative production conditions of the well, the unit pressure drop production under different wellhead pressures was calculated as shown in Table 2.

[0075] Table 2 Production per unit pressure drop under different wellhead pressures

[0076] Wellhead pressure (MPa) <![CDATA[Calculating the production rate per unit pressure drop (10 4 m 3 / MPa)]]> 26.15 86.70 19.19 102.78 13.32 151.71 7.23 212.29

[0077] 3. The relationship curve and formula between the unit pressure drop production and the wellhead pressure of the well were obtained by fitting, as follows: Figure 3 And as shown in the following formula:

[0078] y = 0.3152x 2 -17.282x+322.04

[0079] y represents the wellhead unit pressure drop production, 10 4 m 3 / MPa; x is the wellhead pressure, in MPa.

[0080] 4. Based on the relationship between unit pressure drop output and wellhead pressure, the unit pressure drop output after pressurization (wellhead pressure decreases) is calculated as follows:

[0081] y = 0.3152 × 4.78 2 -17.282 × 4.78 + 322.04 = 246.6

[0082] 5. The wellhead pressure before pressurization was 5.27 MPa, and the wellhead pressure after pressurization was 4.78 MPa, a pressure reduction of 0.49 MPa. The increase in gas production is calculated by multiplying the decrease in wellhead pressure by the unit pressure drop production. The result is 0.49 × 246.6 = 1.209 million cubic meters.

[0083] 6. The daily gas production before pressurization was 4.5 × 10⁻⁶. 4 m 3 After pressurization, the daily gas production is 6.1 × 10⁻⁶. 4 m 3 Increase daily gas production by 1.6 × 10 4 m 3 The production increase duration Δt is obtained by inverse calculation using the area of ​​the triangle:

[0084] Δt=2×120.9÷1.6=151.1d.

[0085] The well has now passed the effective pressurization period, and the actual production per unit pressure drop after pressurization was 235.2 × 10⁻⁶. 4 m 3 / MPa, with a relative error of 1.74%, and the actual pressurization and production increase period was 160 days, with a relative error of 5.89%.

[0086] The shale gas well boosting production time prediction method according to the present invention can be programmed into a computer program and the corresponding program code or instructions can be stored in a computer-readable storage medium. When the program code or instructions are executed by a processor, the processor performs the above method. The processor and memory described below can be included in a computer device.

[0087] Exemplary Example 3

[0088] This exemplary embodiment provides a computer device, including:

[0089] At least one processor;

[0090] A memory storing program instructions configured to be executed by the at least one processor, the program instructions including instructions for executing the shale gas well boosting production enhancement time prediction method according to exemplary embodiment 1 or 2.

[0091] Exemplary Example 4

[0092] This exemplary embodiment provides a computer-readable storage medium.

[0093] The storage medium stores a computer program, and when the computer program instructions are executed by a processor, they implement the shale gas well pressurization and production enhancement time prediction method as described in exemplary embodiment 1 or 2.

[0094] The computer-readable storage medium can be any data storage device that stores data that can be read by a computer system. Examples of computer-readable storage media include: read-only memory, random access memory, read-only optical disc, magnetic tape, floppy disk, optical data storage device, and carrier waves (such as data transmission via the Internet through wired or wireless transmission paths).

[0095] Although the present invention has been described above in conjunction with exemplary embodiments and accompanying drawings, those skilled in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for predicting the production increase time of shale gas well pressurization and extraction, characterized in that, The method includes the following steps: S1. Calculate the unit pressure drop production under different wellhead pressures before the pressure is reduced to the wellhead pressure before the pressure is transmitted. S2. Fit the unit pressure drop production under different wellhead pressures calculated in step S1 to obtain the relationship between single wellhead pressure and unit pressure drop production. S3. Based on the relationship obtained in step S2, calculate the unit pressure drop production when the wellhead pressure is reduced by a certain pressure. S4. Based on the unit pressure drop output calculated in step S3, determine the cumulative increase in output after pressure boosting; S5. Calculate the production increase time after pressurization using the following formula: △t is the pressurization duration, in seconds; △Q is the cumulative increase in output after pressurization, in ten. 4 m 3 △q represents the preset increase in daily gas production after pressurization, 10 4 m 3 / d.

2. The method for predicting the production increase time of shale gas well boosting and extraction according to claim 1, characterized in that, In step S1, the unit pressure drop output is calculated using the following formula: Among them, Q t For the cumulative production at time t, 10 4 m 3 ;△P t P is the wellhead production pressure differential at time t, in MPa; max P represents the peak wellhead pressure, in MPa. t Let t be the wellhead pressure at time t, in MPa.

3. The method for predicting the production increase time of shale gas well boosting extraction according to claim 1, characterized in that, In step S2, the fitting includes fitting using a binomial.

4. The method for predicting the production increase time of shale gas well pressurization and extraction according to claim 1, characterized in that, In step S2, the relation is: in, Let t be the wellhead unit pressure drop production at time t, 10 4 m 3 / MPa; P t Let t be the wellhead pressure at time t, in MPa.

5. The method for predicting the production increase duration of shale gas well pressurization and extraction according to claim 4, characterized in that, a, b, and c are determined by fitting and are dimensionless.

6. The method for predicting the production increase time of shale gas well boosting extraction according to claim 1, characterized in that, Step S2 further includes obtaining the relationship curve between single-wellhead pressure and unit pressure drop production through the fitting.

7. The method for predicting the production increase time of shale gas well pressurization and extraction according to claim 1, characterized in that, In step S3, the certain pressure is determined based on the intake pressure, exhaust pressure, intake temperature, processing volume, and power of the compressor selected for boosting.

8. The method for predicting the production increase time of shale gas well pressurization and extraction according to claim 1, characterized in that, Step S4 includes: Calculate the decrease in wellhead pressure after pressurization, and then multiply this decrease by the unit pressure drop production calculated in step S3 to obtain the cumulative increase in production after pressurization.

9. A computer device, characterized in that, include: At least one processor; A memory storing program instructions configured to be executed by the at least one processor, the program instructions including instructions for performing the method according to any one of claims 1-8.

10. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the method of any one of claims 1-8.

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