Method for calculating undercompaction and overpressure contribution rate of drilled mudstone by using static rock chart method

Abstract

The invention discloses a method for calculating an undercompaction and overpressure contribution rate of drilled mudstone by using a static rock chart method, and relates to the technical field of petroleum and natural gas exploration, and the method comprises the following steps: collecting formation pressure test data of a drilled well in a research area, including formation pressure test points of the drilled well; respectively calculating the overlying rock pressure P0 of the drilled well and the hydrostatic pressure Phydrostatic of the drilled well; determining an overpressure initial depth HTOP; and according to the overlying rock pressure P0 of the drilled well, the hydrostatic pressure P hydrostatic of the drilled well, the formation pressure test point of the drilled well and the overpressure initial depth HTOP, the undercompaction overpressure contribution rate R of the mudstone of the drilled well is obtained. According to the method for calculating the undercompaction and overpressure contribution rate of the drilled mudstone by using the static rock chart method, the calculation complexity and cost are reduced by adopting the static rock chart method.

Description

Technical Field

[0001] The invention relates to the technical field of oil and natural gas exploration, and in particular to a method for calculating the under-compaction overpressure contribution rate of drilled mudstone by using a static lithograph method. Background Art

[0002] Overpressure contribution rate refers to the contribution of different overpressure mechanisms to the formation pressure exceeding the hydrostatic pressure. The study of overpressure contribution rate helps to improve the safety and economy of oil and gas exploration and development, and can also deepen the understanding of geological processes, which has a wide range of application value.

[0003] At present, the commonly used method for calculating the contribution rate of undercompaction overpressure in mudstone is numerical simulation, which uses numerical simulation methods (such as finite element method and finite difference method) to simulate the formation and evolution of fluid pressure to evaluate the contribution of various overpressure formation mechanisms (such as tectonic compression, sedimentary overloading, chemical diagenesis, etc.). However, the numerical simulation method has the disadvantages of complex calculation and difficulty in obtaining parameters, which undoubtedly increase the calculation cost and increase the complexity of operation. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a method for calculating the contribution rate of under-compaction and overpressure of drilled mudstone using the static rock plate method, so as to solve the problems of complex calculation and difficulty in obtaining parameters in the current numerical simulation method.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The invention discloses a method for calculating the undercompaction overpressure contribution rate of drilled mudstone by using a static rock plate method, comprising: Step A: Collect formation pressure test data of wells that have been drilled in the study area, including formation pressure test points of wells that have been drilled; Step B: Calculate the overburden pressure P0 and the hydrostatic pressure P of the drilled well respectively 静水 ; Step C: Determine the overpressure starting depth H TOP ; Step D: According to the overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 and the formation pressure test point of the drilled well and the overpressure starting depth H TOP , and obtain the overpressure contribution rate R of the drilled mudstone undercompaction.

[0006] Specifically, the step B comprises the following steps: Step B1: Collect density logging curves of wells drilled in the study area; Step B2: Calculate the overburden pressure P0 and the hydrostatic pressure P of the well according to the density logging curve of the well. 静水 .

[0007] The calculation expression of the overburden pressure P0 of the drilled well is: (Formula 1) 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 logging curve of the drilled well.

[0008] The hydrostatic pressure P of the drilled well 静水 The calculation expression is: (Formula 2) 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 layer of the density logging curve of the drilled well.

[0009] Specifically, step C comprises the following steps: Step C1: Collect density logging curves, sonic logging curves, and resistivity logging curves of wells drilled in the study area; Step C2: Determine the overpressure starting depth H according to the change characteristics of the density logging curve, acoustic logging curve, and resistivity logging curve of the drilled well TOP .

[0010] Specifically, the step D comprises the following steps: Step D1: The overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 The depth of the formation pressure test point of the drilled well is used as the ordinate and the pressure is used as the abscissa, and the depth and pressure are plotted in the same coordinate system of the relationship between depth and pressure to obtain the overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 A lithostatic chart showing the interaction between depth and pressure at formation pressure test points in the drilled wells; Step D2: The overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 Draw an analysis auxiliary line P on the static rock chart of the interaction between the depth and pressure of the formation pressure test point of the drilled well L , the analysis auxiliary line P L The starting point is the overpressure starting depth H TOP The corresponding hydrostatic pressure point, and the analysis auxiliary line P L Parallel or approximately parallel to the overburden pressure P0 of the drilled well; Step D3: Calculate the total overpressure amplitude P at the depth of the formation pressure test point according to the difference between the pressure at the formation pressure test point of the drilled well and the hydrostatic pressure corresponding to the same depth of the test point.OP (H TEST ); Step D4: The depth of the formation pressure test point of the drilled well is within the analysis auxiliary line P L The difference between the pressure value on the test point and the hydrostatic pressure at the same depth of the test point is used to calculate the undercompaction overpressure amplitude P of the mudstone at the depth of the formation pressure test point. UC (H TEST ); Step D5: Using the total overpressure amplitude P at the formation pressure test point depth OP (H TEST ) and the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ), calculate the contribution rate R of undercompacted overpressure of the drilled mudstone.

[0011] Specifically, the analysis auxiliary line P L Depth on With pressure The relational expression is: (Formula 3) 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] Specifically, the total overpressure amplitude P at the depth of the formation pressure test point OP (H TEST ) is calculated as: (Formula 4) In the formula, Depth of formation pressure test point The total overpressure amplitude; is the pressure value of the formation pressure test point of the drilled well; Depth of formation pressure test point of hydrostatic pressure.

[0013] Specifically, the undercompaction overpressure amplitude P of the mudstone at the depth of the formation pressure test point is UC (H TEST ) is calculated as: (Formula 5) In the formula Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; Depth of formation pressure test point In the analysis of auxiliary line P L Pressure value on Depth of formation pressure test point of hydrostatic pressure.

[0014] Specifically, the calculation expression of the overpressure contribution rate R of the drilled mudstone undercompaction is: % (Formula 6) In the formula Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; Depth of formation pressure test point The total overpressure amplitude.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (I) The present invention discloses a method for calculating the overpressure contribution rate of undercompaction of mudstone in a well using a static lithograph method, comprising: collecting formation pressure test data of wells in a study area, including formation pressure test points of wells; respectively calculating the overburden pressure P0 of the wells and the hydrostatic pressure P 静水 ; Determine the overpressure starting depth H TOP According to the overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 and the formation pressure test point of the drilled well and the overpressure starting depth H TOP , and obtain the under-compaction overpressure contribution rate R of the drilled mudstone. The method for calculating the under-compaction overpressure contribution rate of the drilled mudstone using the static rock plate method disclosed in the present invention adopts the static rock plate method, does not require complex numerical simulation and a large number of parameters, simplifies the calculation process, greatly reduces the calculation cost and data requirements, is easy to be quickly applied in actual exploration, and is particularly suitable for clastic rock formations.

[0016] (ii) Compared with the existing numerical simulation method, the method for calculating the contribution rate of undercompaction and overpressure of drilled mudstone using the static rock plate method disclosed in the present invention has clear operation steps, simple operation, strong applicability, and is suitable for the analysis of undercompaction and overpressure of mudstone in different regions and under various geological conditions, which is convenient for promotion and application in oil and gas exploration and development. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1is the overburden pressure P0 of the well drilled provided in Example 1 of the present invention, the hydrostatic pressure P 静水 A lithostatic chart showing the interaction between depth and pressure at formation pressure test points in the drilled well. DETAILED DESCRIPTION

[0018] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0019] In order to solve the problems of complex calculation and difficulty in obtaining parameters in the current numerical simulation method, the present invention discloses a method for calculating the overpressure contribution rate of undercompaction of mudstone in a drilled well by using a static rock plate method, comprising: collecting formation pressure test data of the wells drilled in the study area, including formation pressure test points of the wells drilled; respectively calculating the overburden pressure P0 of the wells drilled and the hydrostatic pressure P 静水 ; Determine the overpressure starting depth H TOP According to the overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 and the formation pressure test point of the drilled well and the overpressure starting depth H TOP , and obtain the overpressure contribution rate R of the drilled mudstone undercompaction. The method disclosed in the present invention reduces the calculation complexity and cost, is easy to operate and improves the applicability, and provides a new method for the overpressure contribution rate of the drilled mudstone undercompaction for the oil drilling field.

[0020] Example 1: A method for calculating the contribution rate of undercompaction and overpressure of drilled mudstone using the static rock plate method Example 1 provides a method for calculating the undercompaction overpressure contribution rate of drilled mudstone using the static rock plate method, comprising the following steps: Step A: Collect formation pressure test data of wells that have been drilled in the study area, including formation pressure test points of wells that have been drilled.

[0021] Specifically, the depth of the formation pressure test point of the drilled well is 3100m and the pressure value is 52Mpa.

[0022] Step B: Calculate the overburden pressure P0 and the hydrostatic pressure P of the drilled well respectively 静水 , including the following steps: Step B1: Collect density logging curves of wells drilled in the study area; Step B2: Calculate the overburden pressure P0 and the hydrostatic pressure P of the well according to the density logging curve of the well. 静水.

[0023] The calculation expression of the overburden pressure P0 of the drilled well is: (Formula 1) 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 logging curve of the drilled well.

[0024] The hydrostatic pressure P of the drilled well 静水 The calculation expression is: (Formula 2) 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 layer of the density logging curve of the drilled well.

[0025] Specifically, In a drilling application, 1g / cm 3 .

[0026] Step C: Determine the overpressure starting depth H TOP , including the following steps: Step C1: Collect density logging curves, sonic logging curves, and resistivity logging curves of wells drilled in the study area; Step C2: Determine the overpressure starting depth H according to the change characteristics of the density logging curve, acoustic logging curve, and resistivity logging curve of the drilled well TOP .

[0027] Specifically, the overpressure starting depth H TOP In a certain well application, the depth is 2100m.

[0028] Step D: According to the overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 and the formation pressure test point of the drilled well and the overpressure starting depth H TOP , obtaining the overpressure contribution rate R of the drilled mudstone undercompaction, including the following steps: Step D1: The overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 The depth of the formation pressure test point of the drilled well is used as the ordinate and the pressure is used as the abscissa, and the depth and pressure are plotted in the same coordinate system of the relationship between depth and pressure to obtain the overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 A static lithograph showing the interaction between depth and pressure at the formation pressure test point of the drilled well, such as Figure 1 As shown; Step D2: The overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 Draw an analysis auxiliary line P on the static rock chart of the interaction between the depth and pressure of the formation pressure test point of the drilled well L , the analysis auxiliary line P L The starting point is the overpressure starting depth H TOP The corresponding hydrostatic pressure point, and the analysis auxiliary line P L Parallel or approximately parallel to the overburden pressure P0 of the drilled well; Wherein, the analysis auxiliary line P L Depth on With pressure The relational expression is: (Formula 3) 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, Take 40, Take 1250.

[0030] Step D3: Calculate the total overpressure amplitude P at the depth of the formation pressure test point according to the difference between the pressure at the formation pressure test point of the drilled well and the hydrostatic pressure corresponding to the same depth of the test point. OP (H TEST ); Among them, the total overpressure amplitude P at the depth of the formation pressure test point OP (H TEST ) is calculated as: (Formula 4) In the formula, Depth of formation pressure test point The total overpressure amplitude; is the pressure value of the formation pressure test point of the drilled well; Depth of formation pressure test point of hydrostatic pressure.

[0031] Specifically, in a well application, the total overpressure amplitude P at the depth of the formation pressure test point is OP (H TEST ) can be 22Mpa.

[0032] Step D4: The depth of the formation pressure test point of the drilled well is within the analysis auxiliary line P L The difference between the pressure value on the test point and the hydrostatic pressure at the same depth of the test point is used to calculate the undercompaction overpressure amplitude P of the mudstone at the depth of the formation pressure test point. UC (H TEST ); Among them, the under-compaction overpressure amplitude P of the mudstone at the depth of the formation pressure test point UC (H TEST ) is calculated as: (Formula 5) In the formula Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; Depth of formation pressure test point In the analysis of auxiliary line P L Pressure value on Depth of formation pressure test point of hydrostatic pressure.

[0033] Specifically, in a well application, the undercompacted overpressure amplitude P of the mudstone at the depth of the formation pressure test point is UC (H TEST ) is 15Mpa.

[0034] Step D5: Using the total overpressure amplitude P at the formation pressure test point depth OP (H TEST ) and the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ), calculate the contribution rate R of undercompacted overpressure of the drilled mudstone.

[0035] The calculation expression of the overpressure contribution rate R of the drilled mudstone undercompaction is: (Formula 6) In the formula Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; Depth of formation pressure test point The total overpressure amplitude.

[0036] Specifically, in a certain well application, the contribution rate of mudstone undercompaction to overpressure was 68%; 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 calculating the contribution rate of undercompaction and overpressure of drilled mudstone using the static rock plate method, characterized in that: include Step A: Collect formation pressure test data of wells that have been drilled in the study area, including formation pressure test points of wells that have been drilled; Step B: Calculate the overburden pressure P0 and the hydrostatic pressure P of the drilled well respectively 静水 ; Step C: Determine the overpressure starting depth H TOP ; Step D: According to the overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 and the formation pressure test point of the drilled well and the overpressure starting depth H TOP , and obtain the overpressure contribution rate R of the drilled mudstone undercompaction.

2. The method according to claim 1, characterized in that The step B comprises the following steps: Step B1: Collect density logging curves of wells drilled in the study area; Step B2: Calculate the overburden pressure P0 and the hydrostatic pressure P of the well according to the density logging curve of the well. 静水 .

3. The method according to claim 2, characterized in that The calculation expression of the overburden pressure P0 of the drilled well is: (Formula 1) 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 logging curve of the drilled well.

4. The method according to claim 2, characterized in that: The hydrostatic pressure P of the drilled well 静水 The calculation expression is: (Formula 2) 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 layer of the density logging curve of the drilled well.

5. The method according to claim 1, characterized in that The step C comprises the following steps: Step C1: Collect density logging curves, sonic logging curves, and resistivity logging curves of wells drilled in the study area; Step C2: Determine the overpressure starting depth H according to the change characteristics of the density logging curve, acoustic logging curve, and resistivity logging curve of the drilled well TOP .

6. The method according to claim 1, characterized in that The step D comprises the following steps: Step D1: The overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 The depth of the formation pressure test point of the drilled well is used as the ordinate and the pressure is used as the abscissa, and the depth and pressure are plotted in the same coordinate system of the relationship between depth and pressure to obtain the overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 A lithostatic chart showing the interaction between depth and pressure at formation pressure test points in the wells that have been drilled; Step D2: The overburden pressure P0 of the drilled well and the hydrostatic pressure P 静水 Draw an analysis auxiliary line P on the static rock chart of the interaction between the depth and pressure of the formation pressure test point of the drilled well L , the analysis auxiliary line P L The starting point is the overpressure starting depth H TOP The corresponding hydrostatic pressure point, and the analysis auxiliary line P L Parallel or approximately parallel to the overburden pressure P0 of the drilled well; Step D3: Calculate the total overpressure amplitude P at the depth of the formation pressure test point according to the difference between the pressure at the formation pressure test point of the drilled well and the hydrostatic pressure corresponding to the same depth of the test point. OP (H TEST ); Step D4: The depth of the formation pressure test point of the drilled well is within the analysis auxiliary line P L The difference between the pressure value on the test point and the hydrostatic pressure at the same depth of the test point is used to calculate the undercompaction overpressure amplitude P of the mudstone at the depth of the formation pressure test point. UC (H TEST ); Step D5: Using the total overpressure amplitude P at the formation pressure test point depth OP (H TEST ) and the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ), calculate the contribution rate R of undercompacted overpressure of the drilled mudstone.

7. The method according to claim 6, characterized in that The analysis auxiliary line P L Depth on With pressure The relational expression is: (Formula 3) 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. The method according to claim 6, characterized in that The total overpressure amplitude P at the depth of the formation pressure test point OP (H TEST ) is calculated as: (Formula 4) In the formula, Depth of formation pressure test point The total overpressure amplitude; is the pressure value of the formation pressure test point of the drilled well; Depth of formation pressure test point of hydrostatic pressure.

9. The method according to claim 6, characterized in that The under-compaction overpressure amplitude P of the mudstone at the depth of the formation pressure test point UC (H TEST ) is calculated as: (Formula 5) In the formula Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; Depth of formation pressure test point In the analysis of auxiliary line P L Pressure value on Depth of formation pressure test point of hydrostatic pressure.

10. The method according to claim 6, characterized in that The calculation expression of the overpressure contribution rate R of the drilled mudstone undercompaction is: % (Formula 6) In the formula Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; Depth of formation pressure test point The total overpressure amplitude.

Images