Shale formation inter-well interference measuring method and system and storage medium

Abstract

The invention discloses a shale formation inter-well interference determination method and system and a storage medium, and belongs to the technical field of shale formation inter-well interference identification testing. The measurement method at least comprises the following steps: acquiring original inter-well data and processing the original inter-well data to obtain available inter-well data; establishing a pressure interference model based on a linear flow formula and a material balance equation; and inputting the available inter-well data into the interference model to determine the inter-well interference. The original inter-well data at least comprises fracture parameters, formation pressure, bottom hole pressure, well gas yield, inter-well permeability and well depth. The interference model based on the linear flow formula and the material balance equation is constructed, the calculation process is simple, and the calculation result is accurate; the processed inter-well monitoring data is optimized and solved by using a pressure interference model, so that the interference degree between different wells can be quantitatively evaluated, and the source and action mechanism of interference can be accurately judged; the method is simple and easy to implement, and the obtained result is high in accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shale formation interwell interference identification testing, in particular to a shale formation interwell interference determination method and system and a storage medium. BACKGROUND

[0002] With the increase of global energy demand and the decline of conventional oil and gas reserves, unconventional resources such as shale gas are considered as an important energy replacement force that is abundant and reliable. However, as the shale gas development process continues to advance, the number of new wells and fractured wells drilled each year continues to increase, the platform spacing and well spacing continue to shrink, and the interwell interference phenomenon between production wells and fractured wells is increasingly prominent. Interwell interference is an important well spacing optimization indicator, and different development stages have different definitions of interwell interference, such as the fracturing interference formed by the fracture breakthrough (also known as pressure breakthrough) during the fracturing process. Once interwell interference occurs, it will restrict the fracturing effect of new wells and affect the normal production of production wells, bringing many adverse factors to the development of shale gas. Therefore, how to use interwell monitoring data to determine interwell interference is of great significance to effectively avoid or mitigate the adverse effects of interference.

[0003] After determining the interwell interference, measures can be taken in time to adjust the production strategy to avoid or mitigate the adverse effects of interwell interference on production effect and improve the utilization rate of capacity. Effective identification and control of interwell interference can better realize the development potential of oil and gas fields, improve production efficiency, reduce production costs, and maximize the production life of oil and gas fields.

[0004] At present, the methods for identifying and testing shale gas interwell interference mainly include analytical and semi-analytical methods, gray correlation method, numerical simulation method, etc. Among them, the commonly used well test analysis and production decline analysis methods in analytical and semi-analytical methods are widely used in the field because of their simplicity, but the gap between their assumptions and actual shale gas wells is large, making it difficult to accurately predict the degree of interwell interference of shale gas wells; the gray correlation model established by the gray correlation method can only qualitatively analyze factors related to the degree of interwell interference, cannot quantitatively evaluate the degree of interwell interference, and cannot meet the demand of actual field for quantitative evaluation of the degree of interwell interference of shale gas wells; the numerical simulation method fully considers complex fractures and multiphase flow, but it is complex to model and has large calculation amount, it is difficult to model history matching, and it has great application limitations, the process of establishing the model and the final established model can only be applied to the target oil and gas reservoir used, which is not conducive to popularization. Therefore, obtaining a simple and high-precision shale formation interwell interference determination method is one of the problems that those skilled in the art need to solve. SUMMARY

[0005] The present application aims to overcome the problems in the prior art, such as difficulty in accurately predicting the degree of interwell interference in shale gas wells, inability to quantitatively evaluate the degree of interwell interference, and large application limitations, and provides a shale formation interwell interference determination method, system and storage medium.

[0006] To achieve the above-mentioned application purposes, the present application provides the following technical solutions.

[0007] A shale formation interwell interference determination method. The determination method at least comprises: obtaining original interwell data and processing the original interwell data to obtain available interwell data; establishing a pressure interference model based on a linear flow formula and a material balance equation; and inputting the available interwell data into the interference model to determine the interwell interference. Preferably, the original interwell data at least comprises fracture parameters, formation pressure, bottom hole pressure, well gas production, interwell permeability and well depth.

[0008] According to a preferred embodiment, the processing of the original interwell data at least comprises missing value processing and abnormal value removal. The missing value processing can be to establish a linear model based on the original interwell data to predict the data to be filled in by using multiple imputation. The abnormal value removal can be to perform abnormal value inspection on the imputed original interwell data and remove the abnormal values in the imputed original interwell data.

[0009] According to a preferred embodiment, the processing of the interwell data further comprises principal component analysis. Specifically, the principal component analysis is performed on the original interwell data from which the abnormal values are removed to generate the available interwell data.

[0010] According to a preferred embodiment, the pressure interference model is used to evaluate the interwell interference between well 1 and well 2. Preferably, the establishment of the pressure interference model at least comprises: shutting in well 1 for a long enough time, the pressure of which is equal to the initial pressure, and well 2 is kept at normal pressure for production, simulating the corresponding bottom hole pressures of well 1 and well 2, and quantitatively characterizing the degree of interwell interference; and obtaining the corresponding relationship between the pseudo-pressure difference under production correction and time according to the linear flow formula:

[0011]

[0012] In the formula, m(p) is a pseudo-function of gas; L f is the fracture length; p i is the original formation pressure; p w is the bottom hole pressure; q sc is the gas production of the gas well under standard conditions; B gi is the gas volume factor under the original formation pressure; k SRV is the average formation permeability; n f is the number of fractures; h is the well depth; φ SRV is the average formation porosity; μgi viscosity of gas at initial formation pressure; c gi compressibility of gas at initial formation pressure; t is time.

[0013] According to a preferred embodiment, the pseudo pressure difference versus time relationship is converted into a gas pseudo function m(p) versus time t relationship:

[0014]

[0015] According to a preferred embodiment, the establishing of the pressure interference model further comprises: using material balance relationship, for the shut-in well 1, the mass of material flowing into the well 1 from the formation equals the mass of material flowing from the well 1 into the well 2; for the production well 2, the production from the wellbore equals the mass of material flowing into the well fracture from the formation + the mass of material flowing from the well 1 into the well 2. Linear flow formulas for the well 1 and the well 2 are respectively established:

[0016]

[0017]

[0018] According to the material balance equation, we have:

[0019] q sc1 (t) = q sc2 (t)

[0020] q sc4 (t) = q sc2 (t) + q sc3 (t)

[0021] According to the Darcy formula, we have:

[0022]

[0023] wherein, N D is the conductivity coefficient, p wf.1 is the observed point pressure of the well 1, p wf.2 is the observed point pressure of the well 2.

[0024] According to a preferred embodiment, the establishing of the pressure interference model further comprises: using dimensionless pressure to represent the interference signal of the well 1 to the well 2:

[0025]

[0026] According to a preferred embodiment, the establishing of the pressure interference model further comprises: extending the single fracture connection model into a multi-fracture connection model, so as to obtain specific values of the formation well interference.

[0027] The present application also provides a shale formation interwell interference measuring system.

[0028] The present application also provides a storage medium having a readable computer program stored thereon.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The present application constructs an interference model based on the linear flow formula and the material balance equation, and the calculation process is simple, and the calculated data is accurate; and the pressure interference model is used to optimize the calculation of the processed interwell monitoring data, so that the interference degree of different interwells can be quantitatively evaluated, which is helpful for accurately judging the source and mechanism of interference; and the method is simple and easy to implement, and the obtained result is accurate. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Figure 1 is a schematic diagram of a double well with a pressure penetrating fracture;

[0032] Figure 2 Figure 2 is a schematic diagram of interwell pressure penetrating interference of a double well with a pressure penetrating fracture. DETAILED DESCRIPTION

[0033] The present application will be further described in detail below in combination with test examples and specific embodiments. However, it should not be understood that the scope of the above-mentioned subject matter of the present application is limited to the following examples only, and any technology realized based on the content of the present application falls within the scope of the present application.

[0034] In the description of the embodiments of the present application, the terms of orientation or positional relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", and the like, are expressed based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product / device / apparatus of the present application is usually used. These terms of orientation or positional relationship are only for the convenience of describing the present application or simplifying the description in the embodiments, and for the convenience of the skilled person to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship, and therefore cannot be understood as a limitation on the present application.

[0035] In addition, the terms "horizontal", "vertical", "suspended", "parallel", and the like, do not mean that the corresponding device / component / element must be absolutely horizontal or vertical or suspended or parallel, but can be slightly inclined or have a deviation. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined. Alternatively, it can be simplified to understand that the corresponding device / component / element is arranged in the direction of "horizontal", "vertical", "suspended", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction, more preferably an error / deviation of ±8% or less, more preferably an error / deviation of ±6% or less, more preferably an error / deviation of ±5% or less, and more preferably an error / deviation of ±4% or less. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present application.

[0036] In addition, the terms "first", "second", "third", and the like, are only used to distinguish the same or similar components for description, and should not be understood as emphasizing or implying the relative importance of a specific component.

[0037] In addition, in the description of the embodiments of the present application, "several", "a plurality of", and "several" represent at least 2. It can be 2, 3, 4, 5, 6, 7, 8, 9, etc. in any case, or even more than 9.

[0038] In addition, in the description of the technical scheme of the present application, unless otherwise specified / limited / limited, the terms "arrangement", "installation", "connection", "connection", "provided with", "laid", "arrangement" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, such as welding, riveting, bolting, screwing, etc. The connection means commonly used in the art. Such connection can be mechanical connection, or electrical connection or communication connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements.

[0039] Embodiment 1

[0040] The embodiment provides a method for determining interwell interference in shale formation. The method comprises the following steps: obtaining original interwell data and processing the original interwell data to obtain available interwell data; establishing a pressure interference model based on a linear flow formula and a material balance equation; and inputting the available interwell data into the interference model to determine the interwell interference. Preferably, the original interwell data at least comprises fracture parameters, formation pressure, bottom hole pressure, well gas production, interwell permeability and well depth.

[0041] The method for determining interwell interference in shale formation provided by the embodiment has the advantages that: the interference model is established based on the linear flow formula and the material balance equation, the calculation process is simple, and the data obtained by calculation is accurate; the processed interwell monitoring data are optimized and calculated by using the pressure interference model, the interference degree of different interwells can be quantitatively evaluated, the source of interference and the action mechanism can be accurately judged, the method is simple and easy to implement, and the obtained result is accurate.

[0042] Embodiment 2

[0043] The embodiment is a further improvement of the embodiment 1, and the repeated contents will not be described herein. According to a preferred embodiment, the processing of the original interwell data at least comprises missing value processing and abnormal value removal. The missing value processing can be to establish a linear model based on the original interwell data, and to predict the data to be filled by using the linear model. The abnormal value removal can be to remove the abnormal values in the original interwell data after interpolation.

[0044] According to a preferred embodiment, the processing of the interwell data further comprises principal component analysis. Specifically, the principal component analysis is performed on the original interwell data after removal of abnormal values to generate the available interwell data.

[0045] According to a preferred embodiment, the pressure interference model is used to evaluate the interwell interference between well 1 and well 2. Preferably, the establishment of the pressure interference model at least comprises: shutting in the well 1 for a long enough time, so that the pressure is equal to the initial pressure, and the well 2 is kept at normal pressure for production, simulating the corresponding bottom hole pressures of the well 1 and the well 2, and quantitatively representing the interwell interference degree; obtaining the corresponding relationship between the pseudo-pressure difference under the corrected production and time according to the linear flow formula:

[0046]

[0047] In the formula, m(p) is a pseudo function of gas; L f is the fracture length; p i is the original formation pressure; p w is the bottom hole pressure; q sc is the gas production of the gas well under standard conditions; B giis the gas volume coefficient at the original formation pressure; k SRV is the average permeability of the formation; n f is the number of fractures; h is the well depth; φ SRV is the average porosity of the formation; μ gi is the gas viscosity at the original formation pressure; c gi is the gas compressibility coefficient under the original formation pressure; t is time.

[0048] According to a preferred embodiment, the corresponding relationship between the pseudo-pressure difference and time is converted into the relationship between the gas pseudo-function m(p) and time t:

[0049]

[0050] According to a preferred embodiment, the establishment of the pressure interference model also includes: using the material balance relationship, for the shut-in well 1, the mass of material flowing from the formation into well 1 = the mass of material entering well 2 from well 1; for the producing well 2, the mass produced from the wellbore = the mass of material flowing into the fracture of the formation into the well + the mass of material entering well 2 from well 1. The linear flow formulas for well 1 and well 2 are established respectively:

[0051]

[0052]

[0053] According to the material balance equation:

[0054] q sc1 (t) = q sc2 (t)

[0055] q sc4 (t) = q sc2 (t)+q sc3 (t)

[0056] According to Darcy's formula:

[0057]

[0058] Where N D is the conductivity coefficient, p wf.1 is the pressure at the observation point of well 1, p wf.2 is the pressure at the observation point of well 2.

[0059] According to a preferred embodiment, the establishment of the pressure interference model further includes:

[0060] Using the dimensionless pressure P D (t) Characterizes the interference signal of well 1 to well 2:

[0061]

[0062] According to a preferred embodiment, the establishing of the pressure interference model further comprises: extending the single fracture communication model to a multi-fracture communication model, so as to obtain specific values of the interwell interference of the formation.

[0063] Embodiment 3

[0064] This embodiment is a further improvement of Embodiment 1 and Embodiment 2, and the repeated contents will not be described herein.

[0065] This embodiment provides a method for determining the interwell interference of a shale formation, comprising the following steps:

[0066] S1, obtaining original interwell data, which can include fracture parameters, formation pressure, bottom hole pressure, well gas production, interwell permeability and well depth, etc.

[0067] S2, screening usable data, based on geological factors, drilling factors, fracturing factors and production factors, the original interwell data is screened and processed to obtain usable interwell data;

[0068] S3, inputting the usable interwell data into a pressure interference model, and determining the interwell interference by using the interference model.

[0069] Preferably, the original interwell data can be fracture parameters, formation pressure, bottom hole pressure, well gas production, interwell permeability and well depth, etc. obtained by using existing detection equipment. However, there are many missing values in the original interwell data obtained by using the existing detection equipment, and the quality of the data is low.

[0070] The original interwell data is processed into usable interwell data by step S2 to improve the data quality and ensure the accuracy of the output results of the pressure interference model.

[0071] The method for processing the original interwell data into usable interwell data can comprise the following steps:

[0072] A1, missing value processing;

[0073] A2, outlier detection;

[0074] A3, principal component analysis.

[0075] Preferably, the missing value processing means that the missing values in the original interwell data are filled by using multiple imputation method. Specifically, a linear model is established based on the variables except the missing values, and the data to be filled, i.e. the values of the missing values, are predicted.

[0076] Preferably, the outlier test refers to outlier test on the original interwell data after interpolation. The outlier test can include primary test and secondary test. Preferably, the primary test can include determining values in a group of measured values that differ in order of magnitude from other values as outliers, and directly deleting the values. Preferably, the order of magnitude difference can be 10 times, 100 times, etc. of the exponential value. Preferably, the data after the primary test is subjected to secondary test. Preferably, the secondary test can include using the box method and the Mahalanobis distance method to remove values deviating from the average value by more than twice the standard deviation in the measured values as outliers. Preferably, the secondary test combining the box method and the Mahalanobis distance method can be: first, using the Mahalanobis distance method to consider the correlation of each index in the outlier detection, if a certain index has no correlation with other indexes, then using the box method to perform outlier test.

[0077] Preferably, the principal component analysis refers to principal component analysis on the original interwell data after removing outliers using Python language. The specific analysis object is all parameters in the original interwell data except the interwell interference ratio. Through principal component analysis, the data dimension is reduced, and as few new variables as possible are established. The new variables established by principal component analysis retain most of the original data set information, and the new variables are mutually independent. Preferably, the new variables obtained by principal component analysis are the usable interwell data

[0078] Inputting the usable interwell data into the pressure interference model to determine the interwell interference can reduce the complexity and calculation time of the pressure interference model.

[0079] Referring to Figure 1 and Figure 2 , the pressure interference model is established for the case where the pressure is penetrated between two wells. During the fracturing process, the interwell fracture is penetrated, that is, after the interwell pressure penetration occurs, the fracture between the two wells becomes a connected fracture, and the fracturing interference between the two wells is formed. Preferably, when establishing the pressure interference model, it is assumed that well 1 is shut in and the shut-in time is long enough, and well 2 is a production well for normal production.

[0080] Preferably, when establishing the pressure interference model, it is assumed that well 1 is shut in for a long enough time, and the pressure is equal to the initial pressure, and well 2 is kept at normal pressure for production, simulating the corresponding bottom hole pressures of well 1 and well 2. The interwell interference degree is quantitatively characterized; and the corresponding relationship between the pseudo-pressure difference under yield correction and time is obtained according to the linear flow formula:

[0081]

[0082] In the formula, m(p) is a pseudo function of gas; L f is the fracture length, in meters; p i is the original formation pressure, in MPa; p wis the bottom hole pressure, in MPa; q sc is the gas production of the gas well under standard conditions, in units of 10 4 m 3 / d;B gi is the gas volume coefficient at the original formation pressure; k SRV is the average permeability of the formation, in units of 10 -3 μm 2 ;n f is the number of fractures; h is the well depth, in m; φ SRV is the average porosity of the formation, %; μ gi is the gas viscosity at the original formation pressure, in mPa·s; c gi is the gas compressibility coefficient at the original formation pressure, in MPa -1 ; t is time, unit is d.

[0083] Preferably, the above-mentioned correspondence between the pseudo-pressure difference and time is converted into the relationship between the gas pseudo-function m(p) and time t, and the linear flow formula is:

[0084]

[0085] See also Figure 2 , using the material balance relationship, for the shut-in well 1 in the pressure disturbance model, the mass q flowing from the formation into well 1 is: sc1 = the amount of material q entering well 2 from well 1 sc2 For production well 2, the output from the wellbore is q sc4 = the amount of formation flowing into the fracture of this well q sc3 + the amount of material q entering well 2 from well 1 sc2 .

[0086] Based on this, the linear flow formulas for well 1 and well 2 are established respectively:

[0087]

[0088]

[0089] According to the material balance equation:

[0090] q sc1 (t) = q sc2 (t)

[0091] q sc4 (t) = q sc2 (t)+q sc3 (t)

[0092] According to Darcy's formula:

[0093]

[0094] wherein N D is the conductivity coefficient, with units of m 3 / (Pa.s); p wf.1 is the well 1 observation point pressure; p wf.2 is the well 2 observation point pressure.

[0095] well 1 observation point pressure p wf.1 , well 2 observation point pressure p wf.2 , well 1 to well 2 dimensionless pressure P D (t) is characterized by the interference signal of pressure:

[0096]

[0097] The above formula obtains the well-to-well interference caused by a single fracture, and extends the single fracture connection model to multiple fractures, i.e., obtains the specific value of the well-to-well interference of the formation.

[0098] Embodiment 4

[0099] The embodiment provides a deep shale formation well-to-well interference measuring system, and the shale formation well-to-well interference measuring system provided by the embodiment can be used to implement the shale formation well-to-well interference measuring methods of Embodiments 1, 2 and 3. The measuring system can include a monitoring unit, a preprocessing unit, a calculation unit and an output unit.

[0100] The monitoring unit is used to obtain original well-to-well data. Preferably, the original well-to-well data obtained by the monitoring unit can include fracture parameters, formation pressure, bottom hole pressure, well gas production, well-to-well permeability and well depth, etc. The preprocessing unit is used to perform missing value processing, outlier removal and principal component analysis on the original well-to-well data, thereby generating available well-to-well data. The calculation unit is used to calculate the available well-to-well data to obtain the specific value of the well-to-well interference of the formation. Preferably, the calculation unit is configured with a pressure interference model established based on a linear flow formula and a material balance equation. The output unit is used to output the calculation result of the calculation unit.

[0101] Embodiment 5

[0102] The embodiment provides a storage medium having a readable computer program stored thereon. The computer program, when executed by a processor, can implement the steps of the shale formation well-to-well interference measuring methods of Embodiments 1, 2 and 3.

[0103] The above merely describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining interwell interference in a shale formation, comprising: The determination method comprises at least: obtaining original interwell data and processing the original interwell data to obtain available interwell data; a pressure interference model based on a linear flow formula and a material balance equation is established; the available interwell data is input into the interference model to determine interwell interference; wherein the original interwell data at least comprises fracture parameters, formation pressure, bottom hole pressure, well gas production, interwell permeability and well depth.

2. The method of claim 1, wherein, Processing the original interwell data at least comprises missing value processing and abnormal value removal; a linear model is established based on the original interwell data to predict the data to be filled in by using multiple interpolation methods; and abnormal value test is performed on the interpolated original interwell data to remove abnormal values in the interpolated original interwell data.

3. The method of claim 2, wherein, Processing the interwell data further comprises principal component analysis; principal component analysis is performed on the original interwell data from which abnormal values are removed to generate the available interwell data.

4. The method of claim 1, wherein, The pressure interference model is used to evaluate the interwell interference between well 1 and well 2; wherein the establishment of the pressure interference model at least comprises: well 1 is shut in for a long enough time, and its pressure is equal to the initial pressure; well 2 is kept at normal pressure for production, the corresponding bottom hole pressures of well 1 and well 2 are simulated, and the degree of interwell interference is quantitatively characterized; and the corresponding relationship between the pseudo pressure difference and time is obtained according to the linear flow formula: where: m(p) is the gas pseudo function; L f is the fracture length; p i is the initial formation pressure; p w is the bottom hole pressure; q sc is the gas well production at standard conditions; B gi is the gas volume factor at initial formation pressure; k SRV is the average formation permeability; n f is the number of fractures; h is the well depth; φ SRV is the average formation porosity; μ gi is the gas viscosity at initial formation pressure; c gi is the gas compressibility at initial formation pressure; t is time.

5. The method of claim 4, wherein, the corresponding relationship between the pseudo pressure difference and time is converted into the relationship between the gas pseudo function m(p) and time t:

6. The method of claim 5, wherein, the establishment of the pressure interference model further comprises: by using the material balance relationship, for the shut-in well 1, the mass of the material flowing into well 1 from the formation is equal to the mass of the material flowing from well 1 into well 2; for the production well well 2, the amount of the material produced from the wellbore is equal to the amount of the material flowing into the fracture of the well from the formation plus the mass of the material flowing from well 1 into well 2; linear flow formulas of well 1 and well 2 are respectively established: according to the material balance equation, we have: q sc1 (t) = q sc2 (t) q sc4 (t) = q sc2 (t) + q sc3 (t) according to the Darcy formula, we have: where N D is the conductivity coefficient, p wf.1 is the well 1 observation point pressure, p wf.2 is the well 2 observation point pressure.

7. The method of claim 6, wherein, the establishment of the pressure interference model further comprises: the dimensionless pressure is used to represent the interference signal of well 1 to well 2:

8. The method of claim 7, wherein, the establishment of the pressure interference model further comprises: the single-fracture connected model is extended to a multi-fracture connected model, and the specific value of the interwell interference of the formation is obtained.

9. A deep shale formation interwell interference determination system characterized by, The determination system comprises at least: a monitoring unit for obtaining original interwell data, wherein the original interwell data at least comprises fracture parameters, formation pressure, bottom hole pressure, well gas production, interwell permeability and well depth; a preprocessing unit for performing missing value processing, abnormal value removal and principal component analysis on the original interwell data to generate available interwell data; a calculation unit for calculating the available interwell data to obtain the specific value of the interwell interference of the formation, wherein the calculation unit is configured with a pressure interference model established based on a linear flow formula and a material balance equation; an output unit for outputting the calculation result of the calculation unit.

10. A storage medium having stored thereon a readable computer program, characterized in that, The computer program, when executed by a processor, implements the steps of the deep shale formation interwell interference quantitative identification test method according to any one of claims 1-8.

Images