Method and device for predicting depth of overpressure top surface of drilled well

Abstract

The invention relates to a method and device for predicting the overpressure top surface depth of a drilled well, and the method comprises the steps: collecting the formation pressure test data of a to-be-analyzed drilled well in a research area, and enabling the formation pressure test data to comprise a plurality of formation pressure test points of the to-be-analyzed drilled well; obtaining a density curve # imgabs0 # of the whole well section of the drilled well to be analyzed; according to the full-well-section density curve # imgabs1 # of the to-be-analyzed drilled well, the overlying stratum pressure PO of the to-be-analyzed drilled well and the hydrostatic pressure P hydrostatic of the to-be-analyzed drilled well are calculated respectively; and according to the overlying stratum pressure PO of the to-be-analyzed drilled well, the hydrostatic pressure P hydrostatic of the to-be-analyzed drilled well and the formation pressure test points of the to-be-analyzed drilled well, the pre-drilling overpressure top surface depth HTOP of the exploration well is obtained. According to the method for predicting the depth of the overpressure top surface of the drilled well, the application range of overpressure top surface analysis is expanded.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum exploration, and in particular to a method and a device for predicting the depth of the overpressure top surface of a drilled well. Background Art

[0002] The overpressure top is the top boundary of an abnormally high pressure area in an underground formation. Below this depth, the fluid pressure in the formation is significantly higher than the normal formation pressure. Identifying the overpressure top is very important for oil and gas exploration, because overpressure can significantly affect the safety and efficiency of drilling operations, and if overpressure is not correctly predicted and handled, it can lead to dangerous situations such as blowouts.

[0003] In the current analysis of overpressure top surface in drilled wells, the depth of overpressure top surface is usually determined by logging curve characteristics (such as density curve, acoustic wave time difference curve and resistivity curve). However, some well sections in the drilled wells have not been fully logged (there is no logging data at the location of the overpressure top surface). Therefore, the existing overpressure top surface depth prediction method cannot predict the depth of overpressure top surface in the drilled wells when the logging data is incomplete. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a method and device for predicting the depth of the overpressure top surface of a drilled well, so as to solve the problem that the existing overpressure top surface depth prediction method cannot predict the depth of the overpressure top surface of a drilled well when the logging data is incomplete.

[0005] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention discloses a method for predicting the depth of the overpressure top surface of a drilled well, comprising: Step A: Collect formation pressure test data of the wells to be analyzed in the study area, including multiple formation pressure test points of the wells to be analyzed; Step B: Obtain the density curve of the entire well section to be analyzed ; Step C: Based on the density curve of the entire well section to be analyzed , respectively calculate the overburden pressure P of the well to be analyzed O and the hydrostatic pressure P of the well to be analyzed 静水 ; Step D: According to the overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 and the plurality of formation pressure test points to be analyzed, and the overpressure top depth H before drilling of the exploration well is obtained. TOP .

[0006] Specifically, the step B comprises the following steps: Step B1: Collect the density data of the wells to be analyzed in the study area and the density data of the adjacent wells; Step B2: Based on the density data of adjacent wells, establish a trend curve of density variation with burial depth in the study area; Step B3: Obtain the density curve of the entire well section of the well to be analyzed based on the density curve of the well to be analyzed and the trend curve of density change with burial depth in the study area .

[0007] Specifically, the density curve of the entire well section to be analyzed is The calculation expression is: (Formula 1) In the formula, is the density curve of the well to be analyzed; is the trend curve of density changing with burial depth in the study area; is the fusion coefficient.

[0008] Specifically, the overburden pressure P of the well to be analyzed is O The calculation expression is: (Formula 2) In the formula, is the depth of the overlying rock layer; It is the density corresponding to the depth H of the overlying rock formation of the density curve of the entire well section to be analyzed.

[0009] Specifically, the hydrostatic pressure P of the well to be analyzed is 静水 The calculation expression is: (Formula 3) In the formula, is the depth of the overlying rock layer; It is the formation water density corresponding to the depth H of the overlying rock formation of the full-well density curve to be analyzed.

[0010] Specifically, the step D comprises the following steps: Step D1: The overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 The pressure test points of the drilled wells to be analyzed are plotted in the coordinate system of depth and pressure to obtain the overburden pressure P of the drilled wells to be analyzed. O , the hydrostatic pressure P of the well to be analyzed 静水 Interaction plots of depth and pressure for multiple drilled formation pressure test points to be analyzed; Step D2: In the overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 Draw an analysis auxiliary line P on the interactive diagram of depth and pressure of multiple well formation pressure test points to be analyzed L , the analysis auxiliary line P L Parallel or approximately parallel to the overburden pressure P of the well to be analyzed O And it should pass through the dense area of ​​the drilled formation pressure test points to be analyzed as much as possible; Step D3: According to the analysis of auxiliary line P L The hydrostatic pressure P of the well to be analyzed 静水 The depth at the intersection point gives the overpressure top depth H of the well to be analyzed. TOP .

[0011] Wherein, the analysis auxiliary line P L Depth on With pressure The relational expression is: (Formula 4) In the formula, The auxiliary line P for this analysis L Depth on; The auxiliary line P for this analysis L Depth on The pressure of is the slope; is the intercept.

[0012] Wherein, the analysis auxiliary line P L The hydrostatic pressure P of the well to be analyzed 静水 The depth at the intersection is the overpressure top depth H of the well to be analyzed. TOP .

[0013] In a second aspect, the present invention discloses a device for predicting the depth of the overpressure top surface of a drilled well, comprising: The first unit is used to collect formation pressure test data of the wells to be analyzed in the study area, including multiple formation pressure test points of the wells to be analyzed; The second unit is used to obtain the density curve of the entire well section to be analyzed. ; The third unit is used to analyze the density curve of the entire well section to be drilled. , respectively calculate the overburden pressure P of the well to be analyzed O and the hydrostatic pressure P of the well to be analyzed 静水 ; The fourth unit is used to determine the overburden pressure P of the well to be analyzed according to the overburden pressure P O , the hydrostatic pressure P of the well to be analyzed 静水 and the plurality of formation pressure test points to be analyzed, and the overpressure top depth H before drilling of the exploration well is obtained. TOP .

[0014] In a third aspect, the present invention discloses a computer-readable storage medium, characterized in that a computer program is stored thereon, and the computer program implements the steps of the above method when executed by a processor.

[0015] In a fourth aspect, the present invention discloses a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (I) The present invention discloses a method for predicting the depth of the overpressure top surface of a drilled well, comprising: collecting formation pressure test data of the drilled wells to be analyzed in the study area, including multiple formation pressure test points of the drilled wells to be analyzed; obtaining the density curve of the entire well section of the drilled wells to be analyzed; ; According to the density curve of the entire well section to be analyzed , respectively calculate the overburden pressure P of the well to be analyzed O and the hydrostatic pressure P of the well to be analyzed 静水 According to the overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 and the plurality of formation pressure test points to be analyzed, and the overpressure top depth H before drilling of the exploration well is obtained. TOP The method for predicting the overpressure top depth of a well disclosed in the present invention expands the application scope of overpressure top analysis, solves the problem that the existing overpressure top depth prediction method cannot predict the overpressure top depth of a well when the logging data is incomplete, and enables the prediction of the overpressure top depth to be performed even when the logging data is missing or incomplete, greatly expanding the application scope of the overpressure top depth prediction.

[0017] (ii) The present invention discloses a method for predicting the depth of the overpressure top surface of a drilled well, thereby improving the reliability of the overpressure top surface analysis: by introducing new analysis methods and means, the depth and characteristics of the overpressure top surface can be more accurately judged even when the logging data is incomplete, thereby avoiding misjudgment or omission caused by missing data and improving the reliability of the analysis.

[0018] (III) The present invention discloses a method for predicting the depth of the overpressure top surface of a drilled well, which is simple to operate and easy to implement. Moreover, the method has clear steps and a relatively simple calculation process, which is convenient for promotion and application in actual work, thereby improving work efficiency. The method is particularly suitable for predicting the depth of the overpressure top surface of a well caused by under-compaction overpressure of mudstone in clastic rock formations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the overburden pressure P of the well to be analyzed provided in Example 1 of the present invention O , the hydrostatic pressure P of the well to be analyzed 静水 Interaction plot of depth versus pressure for multiple formation pressure test points in the wells to be analyzed. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is described clearly and completely. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In order to solve the problem that the existing overpressure top depth prediction method cannot predict the overpressure top depth of a well when the well logging data is incomplete, the present invention discloses a method for predicting the overpressure top depth of a well, comprising: collecting formation pressure test data of the wells to be analyzed in the study area, including multiple formation pressure test points of the wells to be analyzed; obtaining the density curve of the whole well section of the well to be analyzed ; According to the density curve of the entire well section to be analyzed , respectively calculate the overburden pressure P of the well to be analyzed O and the hydrostatic pressure P of the well to be analyzed 静水 According to the overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 and the plurality of formation pressure test points to be analyzed, and the overpressure top depth H before drilling of the exploration well is obtained. TOP The method for predicting the depth of the overpressure top surface of a drilled well disclosed by the present invention improves the reliability of the overpressure top surface analysis of the drilled well when the well logging data is incomplete, and provides a new overpressure top surface analysis method for the oil drilling field.

[0022] Example 1: A method for predicting the depth of the overpressure top surface of a drilled well Embodiment 1 provides a method for predicting the depth of the overpressure top surface of a drilled well, comprising the following steps: Step A: Collect formation pressure test data of the wells to be analyzed in the study area, including multiple formation pressure test points of the wells to be analyzed; Step B: Obtain the density curve of the entire well section to be analyzed , including the following steps: Step B1: Collect the density data of the wells to be analyzed in the study area and the density data of the adjacent wells; Step B2: Based on the density data of adjacent wells, establish a trend curve of density variation with burial depth in the study area; Step B3: Obtain the density curve of the entire well section of the well to be analyzed based on the density curve of the well to be analyzed and the trend curve of density change with burial depth in the study area .

[0023] The density curve of the entire well section to be analyzed is The calculation expression is: (Formula 1) In the formula, is the density curve of the well to be analyzed; is the trend curve of density changing with burial depth in the study area; is the fusion coefficient.

[0024] Specifically, in the density curve of the well to be analyzed When it is a non-empty value, the fusion coefficient Take 0; in the density curve of the well to be analyzed When it is null, the fusion coefficient Take 1.

[0025] Step C: Based on the density curve of the entire well section to be analyzed , respectively calculate the overburden pressure P of the well to be analyzed O and the hydrostatic pressure P of the well to be analyzed 静水 ; The overburden pressure P of the well to be analyzed is O The calculation expression is: (Formula 2) In the formula, is the depth of the overlying rock layer; It is the density corresponding to the depth H of the overlying rock formation of the density curve of the entire well section to be analyzed.

[0026] The hydrostatic pressure P of the well to be analyzed 静水 The calculation expression is: (Formula 3) In the formula, is the depth of the overlying rock layer; It is the formation water density corresponding to the depth H of the overlying rock formation of the full-well density curve to be analyzed.

[0027] Specifically, In the implementation application of a well to be analyzed, 1g / cm 3 .

[0028] Step D: According to the overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 and the plurality of formation pressure test points to be analyzed, and the overpressure top depth H before drilling of the exploration well is obtained. TOP , including the following steps: Step D1: The overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 The pressure test points of the drilled wells to be analyzed are plotted in the coordinate system of depth and pressure to obtain the overburden pressure P of the drilled wells to be analyzed. O , the hydrostatic pressure P of the well to be analyzed 静水 Interaction diagram of depth and pressure of multiple drilled formation pressure test points to be analyzed, such as Figure 1 As shown; Step D2: In the overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 Draw an analysis auxiliary line P on the interactive diagram of depth and pressure of multiple well formation pressure test points to be analyzed L , the analysis auxiliary line P L Parallel or approximately parallel to the overburden pressure P of the well to be analyzed O And it should pass through the dense area of ​​the drilled formation pressure test points to be analyzed as much as possible; Wherein, the analysis auxiliary line P L Depth on With pressure The relational expression is: (Formula 4) In the formula, The auxiliary line P for this analysis L Depth on; The auxiliary line P for this analysis L Depth on The pressure of is the slope; is the intercept.

[0029] Specifically, in an application where a well has been drilled and is to be analyzed, Take 40, Take 1100.

[0030] Step D3: According to the analysis of auxiliary line P L The hydrostatic pressure P of the well to be analyzed 静水 The depth at the intersection point gives the overpressure top depth H of the well to be analyzed. TOP .

[0031] Specifically, the analysis auxiliary line P L The hydrostatic pressure P of the well to be analyzed 静水 The depth at the intersection is the overpressure top depth H of the well to be analyzed. TOP .

[0032] Specifically, in the implementation application of a certain well to be analyzed, the overpressure top depth H of the well to be analyzed is TOP It is 1800m.

[0033] Example 2: A device for predicting the depth of the overpressure top surface of a drilled well Embodiment 2 provides a device for predicting the depth of the overpressure top surface of a drilled well, comprising: The first unit is used to collect formation pressure test data of the wells to be analyzed in the study area, including multiple formation pressure test points of the wells to be analyzed; The second unit is used to obtain the density curve of the entire well section to be analyzed. ; The third unit is used to analyze the density curve of the entire well section to be drilled. , respectively calculate the overburden pressure P of the well to be analyzed O and the hydrostatic pressure P of the well to be analyzed 静水 ; The fourth unit is used to determine the overburden pressure P of the well to be analyzed according to the overburden pressure P O , the hydrostatic pressure P of the well to be analyzed 静水 and the plurality of formation pressure test points to be analyzed, and the overpressure top depth H before drilling of the exploration well is obtained. TOP .

[0034] Embodiment 3: A computer-readable storage medium Embodiment 3 provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the method of embodiment 1 are implemented.

[0035] Embodiment 4: A computer device Embodiment 4 provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method of embodiment 1 when executing the computer program.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for predicting the depth of the overpressure top surface of a drilled well, characterized in that: include Step A: Collect formation pressure test data of the wells to be analyzed in the study area, including multiple formation pressure test points of the wells to be analyzed; Step B: Obtain the density curve of the entire well section to be analyzed ; Step C: Based on the density curve of the entire well section to be analyzed , respectively calculate the overburden pressure P of the well to be analyzed O and the hydrostatic pressure P of the well to be analyzed 静水 ; Step D: According to the overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 and the plurality of formation pressure test points to be analyzed, and the overpressure top depth H before drilling of the exploration well is obtained. TOP .

2. The method for predicting the depth of the overpressure top surface of a drilled well according to claim 1, characterized in that: The step B comprises the following steps: Step B1: Collect the density data of the wells to be analyzed in the study area and the density data of the adjacent wells; Step B2: Based on the density data of adjacent wells, establish a trend curve of density variation with burial depth in the study area; Step B3: Obtain the density curve of the entire well section of the well to be analyzed based on the density curve of the well to be analyzed and the trend curve of density change with burial depth in the study area. .

3. The method for predicting the depth of the overpressure top surface of a drilled well according to claim 1, characterized in that: The density curve of the entire well section to be analyzed The calculation expression is: (Formula 1) In the formula, is the density curve of the well to be analyzed; is the trend curve of density changing with burial depth in the study area; is the fusion coefficient.

4. The method for predicting the depth of the overpressure top surface of a drilled well according to claim 1, characterized in that: The overburden pressure P of the well to be analyzed O The calculation expression is: (Formula 2) In the formula, is the depth of the overlying rock layer; It is the density corresponding to the depth H of the overlying rock formation of the density curve of the entire well section to be analyzed.

5. The method for predicting the depth of the overpressure top surface of a drilled well according to claim 1, characterized in that: The hydrostatic pressure P of the well to be analyzed 静水 The calculation expression is: (Formula 3) In the formula, is the depth of the overlying rock layer; It is the formation water density corresponding to the depth H of the overlying rock formation of the full-well density curve to be analyzed.

6. The method for predicting the depth of the overpressure top surface of a drilled well according to claim 1, characterized in that: The step D comprises the following steps: Step D1: The overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 The pressure test points of the drilled wells to be analyzed are plotted in the coordinate system of depth and pressure to obtain the overburden pressure P of the drilled wells to be analyzed. O , the hydrostatic pressure P of the well to be analyzed 静水 Interaction plots of depth and pressure for multiple drilled formation pressure test points to be analyzed; Step D2: In the overburden pressure P of the well to be analyzed O , the hydrostatic pressure P of the well to be analyzed 静水 Draw an analysis auxiliary line P on the interactive diagram of depth and pressure of multiple well formation pressure test points to be analyzed L , the analysis auxiliary line P L Parallel or approximately parallel to the overburden pressure P of the well to be analyzed O And it should pass through the dense area of ​​the drilled formation pressure test points to be analyzed as much as possible; Step D3: According to the analysis of auxiliary line P L The hydrostatic pressure P of the well to be analyzed 静水 The depth at the intersection point gives the overpressure top depth H of the well to be analyzed. TOP .

7. The method for predicting the depth of the overpressure top surface of a drilled well according to claim 5, characterized in that: The analysis auxiliary line P L Depth on With pressure The relational expression is: (Formula 4) In the formula, The auxiliary line P for this analysis L Depth on; The auxiliary line P for this analysis L Depth on The pressure of is the slope; is the intercept.

8. A device for predicting the depth of the overpressure top surface of a drilled well, characterized in that: include The first unit is used to collect formation pressure test data of the wells to be analyzed in the study area, including multiple formation pressure test points of the wells to be analyzed; The second unit is used to obtain the density curve of the entire well section to be analyzed. ; The third unit is used to analyze the density curve of the entire well section to be drilled. , respectively calculate the overburden pressure P of the well to be analyzed O and the hydrostatic pressure P of the well to be analyzed 静水 ; The fourth unit is used to determine the overburden pressure P of the well to be analyzed according to the overburden pressure P O , the hydrostatic pressure P of the well to be analyzed 静水 and the plurality of formation pressure test points to be analyzed, and the overpressure top depth H before drilling of the exploration well is obtained. TOP .

9. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a processor, the steps of any one of the methods described in claims 1 to 7 are implemented.

10. A computer device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any one of the methods of claims 1 to 7 when executing the computer program.

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