Method for calculating undercompaction and overpressure contribution rate of drilled mudstone by using equivalent depth method
Calculate the contribution rate of mudstone under-compact overpressure by equivalent depth method, and solves the problems of complex calculation and difficult parameter acquisition of numerical simulation methods, achieving a faster and more efficient analysis process.
Patent Information
- Application Number
- CN202411799450.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-03-14
AI Technical Summary
The existing numerical simulation method has problems such as complex calculation and difficult to obtain parameters when calculating the contribution rate of mudstone under-compacting overpressure, resulting in high calculation costs and complex operation.
The equivalent depth method is used to collect the formation pressure test data of drilled wells, calculate the overlying rock formation pressure and hydrostatic pressure, and determine the equivalent depth of the formation pressure test point, and then calculate the contribution rate of mudstone under-compact overpressure.
The calculation process is simplified, the calculation cost and data requirements are reduced, and the analysis of mudstone under-compact overpressure contribution rate is faster and more efficient, and is suitable for different regions and multiple geological conditions.
Smart Images
Figure CN119623347A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of oil and gas exploration, and in particular to a method for calculating the overpressure contribution rate of under-compaction of drilled mudstone by using an equivalent depth 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 overpressure contribution rate of undercompaction of drilled mudstone using the equivalent depth 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: In a first aspect, the present invention discloses a method for calculating the overpressure contribution rate of undercompaction of drilled mudstone using an equivalent depth 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 equivalent depth H of the formation pressure test point 等效深度 ; 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 equivalent depth H of the formation pressure test point depth 等效深度 , 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:
[0008] 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.
[0009] The hydrostatic pressure P of the drilled well 静水 The calculation expression is:
[0010] 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.
[0011] Specifically, step C comprises the following steps: Step C1: Collect the acoustic logging curves of the wells drilled in the study area; Step C2: Determine the equivalent depth H of the formation pressure test point according to the acoustic logging curve of the drilled well 等效深度 .
[0012] 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 the depth and the pressure; Step D2: Based on the equivalent depth H of the formation pressure test point depth 等效深度 , respectively calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ) and the hydrostatic pressure corresponding to the depth of the formation pressure test point, and the difference is taken as the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ); Step D3: Calculate the total overpressure amplitude P at the depth of the formation pressure test point according to the pressure at the drilled formation pressure test point and the difference between the hydrostatic pressure at the same depth of the test point OP (H TEST ); Step D4: According to the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ) and the total overpressure amplitude P at the depth of the formation pressure test point OP (H TEST ), calculate the contribution rate R of undercompacted overpressure of the drilled mudstone.
[0013] Specifically, step D2 includes the following steps: Step D21: Based on the equivalent depth H of the formation pressure test point depth 等效深度 , calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ); Step D22: According to the formation pressure P at the depth of the formation pressure test point ED (H TEST ), calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ) and the hydrostatic pressure corresponding to the depth of the formation pressure test point, as the undercompaction overpressure amplitude P of the mudstone at the formation pressure test point UC (H TEST ).
[0014] Wherein, the formation pressure P at the depth of the formation pressure test point ED (H TEST ) is calculated as:
[0015] In the formula, is the hydrostatic pressure at the equivalent depth of the formation pressure test point; is the overburden pressure at the depth of the formation pressure test point; It is the overburden pressure at the equivalent depth of the formation pressure test point.
[0016] 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:
[0017] In the formula, Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; is the formation pressure at the depth of the formation pressure test point; Depth of formation pressure test point The corresponding hydrostatic pressure.
[0018] Among them, the total overpressure amplitude P at the depth of the formation pressure test point OP (H TEST ) is calculated as:
[0019] 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.
[0020] The calculation expression of the overpressure contribution rate R of the drilled mudstone undercompaction is:
[0021] 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.
[0022] 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 drilled well by using the equivalent depth 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 equivalent depth H of the formation pressure test point 等效深度 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 equivalent depth H of the formation pressure test point depth 等效深度 , and obtain the under-compaction overpressure contribution rate R of the drilled mudstone. The method disclosed in the present invention for calculating the under-compaction overpressure contribution rate of the drilled mudstone using the equivalent depth method does not require complex numerical simulation and a large number of parameters, simplifies the calculation process, significantly reduces the calculation cost and data requirements, and enables it to be applied to actual exploration more quickly.
[0023] (ii) Compared with the existing numerical simulation methods, the method disclosed in the present invention for calculating the contribution rate of undercompacted overpressure of drilled mudstone using the equivalent depth method has clearer and simpler operation steps, is suitable for the analysis of undercompacted overpressure of mudstone in different regions and under various geological conditions, and is convenient for promotion and use in oil and gas exploration and development. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 is the overburden pressure P0 of the well drilled provided in Example 1 of the present invention, the hydrostatic pressure P 静水 An interactive diagram showing the relationship between depth and pressure at formation pressure test points in drilled wells. DETAILED DESCRIPTION
[0025] 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.
[0026] 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 drilled mudstone using the equivalent depth method, comprising: collecting formation pressure test data of the drilled wells in the study area, including the formation pressure test points of the drilled wells; respectively calculating the overburden pressure P0 of the drilled wells and the hydrostatic pressure P 静水 ; Determine the equivalent depth H of the formation pressure test point 等效深度 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 equivalent depth H of the formation pressure test point depth 等效深度 , and obtain the overpressure contribution rate R of the drilled mudstone undercompaction. The method disclosed in the present invention provides a new mudstone undercompaction overpressure contribution rate analysis method for the oil drilling field by simplifying the calculation process, reducing costs and improving operability.
[0027] Example 1: A method for calculating the contribution rate of undercompaction and overpressure of drilled mudstone using the equivalent depth method Example 1 provides a method for calculating the overpressure contribution rate of undercompaction of drilled mudstone using the equivalent depth method, comprising the following steps: Step A: Collect formation pressure test data of wells drilled in the study area, including formation pressure test points of wells drilled.
[0028] Specifically, the depth of the formation pressure test point of the drilled well is 3100m and the pressure value is 52Mpa.
[0029] 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 .
[0030] 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.
[0031] 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.
[0032] Specifically, In a well application, 1 g / cm 3 .
[0033] Step C: Determine the equivalent depth H of the formation pressure test point 等效深度 , including the following steps: Step C1: Collect the acoustic logging curves of the wells drilled in the study area; Step C2: Determine the equivalent depth H of the formation pressure test point according to the acoustic logging curve of the drilled well 等效深度 .
[0034] Specifically, in an implementation application of a certain well that has been drilled, the depth of the formation pressure test point of the well that has been drilled is 3100m, and its equivalent depth is 2300m.
[0035] 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 equivalent depth H of the formation pressure test point depth 等效深度 , 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 and the interactive diagram of the relationship between depth and pressure at the formation pressure test points of the drilled wells, such as Figure 1 shown.
[0036] Step D2: Based on the equivalent depth H of the formation pressure test point depth 等效深度 , respectively calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ) and the hydrostatic pressure corresponding to the depth of the formation pressure test point, and the difference is taken as the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ), including the following steps: Step D21: Based on the equivalent depth H of the formation pressure test point depth 等效深度 , calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ); Among them, the equivalent depth method is used to calculate the formation pressure P at the depth of the formation pressure test point. ED (H TEST ) is: (Formula 3) In the formula, is the hydrostatic pressure at the equivalent depth of the formation pressure test point; is the overburden pressure at the depth of the formation pressure test point; It is the overburden pressure at the equivalent depth of the formation pressure test point.
[0037] Specifically, in a well application, P ED (H TEST ) is 44Mpa.
[0038] Step D22: According to the formation pressure P at the depth of the formation pressure test point ED (H TEST ), calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ) and the hydrostatic pressure corresponding to the depth of the formation pressure test point, as the undercompaction overpressure amplitude P of the mudstone at 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 4) In the formula, Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; is the formation pressure at the depth of the formation pressure test point; Depth of formation pressure test point The corresponding hydrostatic pressure.
[0039] 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 13Mpa.
[0040] Step D3: Calculate the total overpressure amplitude P at the depth of the formation pressure test point according to the pressure at the drilled formation pressure test point and the difference between the hydrostatic pressure at 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 5) 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.
[0041] Specifically, in a well application, the total overpressure amplitude P at the depth of the formation pressure test point is OP (H TEST ) is 22Mpa.
[0042] Step D4: According to the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ) and the total overpressure amplitude P at the depth of the formation pressure test point OP (H TEST ), calculate the contribution rate R of undercompacted overpressure of the drilled mudstone.
[0043] 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.
[0044] Specifically, in a certain well application, the overpressure contribution rate R of the drilled mudstone undercompaction is 60%.
[0045] 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 equivalent depth 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 equivalent depth H of the formation pressure test point 等效深度 ; 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 equivalent depth H of the formation pressure test point depth 等效深度 , 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: In the formula, is the depth of the overlying rock layer; is the density corresponding to the depth H of the overburden of the density logging curve of the drilled well; The hydrostatic pressure P of the drilled well 静水 The calculation expression is: 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.
4. The method according to claim 1, characterized in that: The step C comprises the following steps: Step C1: Collect the acoustic logging curves of the wells drilled in the study area; Step C2: Determine the equivalent depth H of the formation pressure test point according to the acoustic logging curve of the drilled well 等效深度 .
5. 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 the depth and the pressure; Step D2: Based on the equivalent depth H of the formation pressure test point depth 等效深度 , respectively calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ) and the hydrostatic pressure corresponding to the depth of the formation pressure test point, and the difference is taken as the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ); Step D3: Calculate the total overpressure amplitude P at the depth of the formation pressure test point according to the pressure at the drilled formation pressure test point and the difference between the hydrostatic pressure at the same depth of the test point OP (H TEST ); Step D4: According to the mudstone undercompaction overpressure amplitude P at the depth of the formation pressure test point UC (H TEST ) and the total overpressure amplitude P at the depth of the formation pressure test point OP (H TEST ), calculate the contribution rate R of undercompacted overpressure of the drilled mudstone.
6. The method according to claim 5, characterized in that The step D2 comprises the following steps: Step D21: Based on the equivalent depth H of the formation pressure test point depth 等效深度 , calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ); Step D22: According to the formation pressure P at the depth of the formation pressure test point ED (H TEST ), calculate the formation pressure P at the depth of the formation pressure test point ED (H TEST ) and the hydrostatic pressure corresponding to the depth of the formation pressure test point, as the undercompaction overpressure amplitude P of the mudstone at the formation pressure test point UC (H TEST ).
7. The method according to claim 6, characterized in that The formation pressure P at the depth of the formation pressure test point ED (H TEST ) is calculated as: In the formula, is the hydrostatic pressure at the equivalent depth of the formation pressure test point; is the overburden pressure at the depth of the formation pressure test point; It is the overburden pressure at the equivalent depth of the formation pressure test point.
8. 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: In the formula, Depth of formation pressure test point The magnitude of overpressure of mudstone undercompaction; is the formation pressure at the depth of the formation pressure test point; Depth of formation pressure test point The corresponding hydrostatic pressure.
9. The method according to claim 5, characterized in that The total overpressure amplitude P at the depth of the formation pressure test point OP (H TEST ) is calculated as: 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.
10. The method according to claim 5, characterized in that The calculation expression of the overpressure contribution rate R of the drilled mudstone undercompaction is: 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.