A method and apparatus for predicting the depth of overpressure top surface before drilling in exploration wells.

Abstract

This invention relates to a method and apparatus for predicting the depth of the overpressure top surface before drilling in exploration wells. The method includes: collecting formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points; obtaining the density curves of the exploration wells; and calculating the overlying strata pressure P of the exploration wells based on the density curves. O and the hydrostatic pressure P of the exploration well 静水 According to the overlying strata pressure P of the exploration well O The hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP This invention relates to a method for predicting the depth of the overpressure top surface before drilling in exploration wells. It utilizes the trend of density variation with burial depth and analysis of formation pressure test data from drilled wells to avoid the uncertainty caused by relying solely on formation velocity to predict the overpressure top surface, thereby improving the accuracy of overpressure top surface prediction before drilling in exploration wells.

Description

Technical Field

[0001] This invention relates to the field of petroleum exploration technology, specifically to a method and apparatus for predicting the depth of the overpressure top surface before drilling exploration wells. Background Technology

[0002] The overpressure cap is the top boundary of an abnormally high-pressure zone in a subsurface formation. Below this depth, the fluid pressure in the formation is significantly higher than the normal formation pressure. Identifying the overpressure cap is crucial for oil and gas exploration because overpressure can significantly impact drilling safety and operational efficiency, and if overpressure is not properly predicted and managed, it can lead to dangerous situations such as well blowouts.

[0003] Current research on pre-drilling overpressure top depth prediction in exploration wells typically utilizes seismic formation velocity characteristics to predict the depth of the overpressure top. However, due to the difficulty in obtaining accurate formation velocity data pre-drilling, the prediction results for the depth of the pre-drilling overpressure top in exploration wells exhibit significant uncertainty and large prediction errors. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method and apparatus for predicting the overpressure top depth before drilling in exploration wells, thereby solving the problems of large uncertainty and large prediction errors in the current prediction results of the overpressure top depth before drilling in exploration wells.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention discloses a method for predicting the depth of the overpressure top surface before drilling in an exploration well, including...

[0007] Collect formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points;

[0008] Obtain the density curve of the exploration well;

[0009] Based on the density curves of the exploration wells, calculate the overlying strata pressure P of each exploration well. O and the hydrostatic pressure P of the exploration well 静水 ;

[0010] According to the overlying strata pressure P of the exploration well O The hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP .

[0011] Obtaining the density curve of the exploration well includes the following steps:

[0012] Collect density data of drilled wells in the study area;

[0013] A trend curve of density variation with burial depth in the study area was established based on the density data of the drilled wells in the study area.

[0014] Based on the trend curve of density variation with burial depth in the study area, the density curve of the exploration well is obtained.

[0015] Specifically, the overlying strata pressure P of the exploration well O The calculation expression is:

[0016] (Equation 1)

[0017] In the formula, The depth of the overlying rock strata;

[0018] This represents the density at depth H of the overlying strata in the density curve of the exploration well.

[0019] Specifically, the hydrostatic pressure P of the exploration well 静水 The calculation expression is:

[0020] (Equation 2)

[0021] In the formula, The depth of the overlying rock strata;

[0022] This represents the formation water density at depth H of the overlying strata in the density curve of the exploration well.

[0023] Among them, the depth H of the pre-drilling overpressure top surface of the exploration well was obtained. TOP Includes the following steps:

[0024] The pressure P of the overlying strata of the exploration well O The hydrostatic pressure P of the exploration well 静水 The multiple drilled formation pressure test points are plotted in the same depth-pressure coordinate system to obtain the overlying strata pressure P of the exploration well. O The hydrostatic pressure P of the exploration well 静水 Interaction graph of depth and pressure with multiple drilled formation pressure test points;

[0025] The pressure P of the overlying strata above the exploration well O The hydrostatic pressure P of the exploration well 静水 Draw an analysis auxiliary line P on the depth-pressure interaction graph of multiple drilled formation pressure test points. L The analysis auxiliary line P L The pressure P of the overlying strata parallel or approximately parallel to the exploration well. O And it should pass through areas with a high density of drilled formation pressure test points as much as possible;

[0026] Based on the analysis of auxiliary line P L With hydrostatic pressure P 静水 The depth at the intersection point yields the pre-drilling overpressure top surface depth H of the exploration well. TOP .

[0027] Specifically, the analysis auxiliary line P L Depth With pressure The relational expression is:

[0028] (Equation 3)

[0029] In the formula, For this analysis, the auxiliary line P L Depth above;

[0030] For this analysis, the auxiliary line P L Depth Pressure at the location;

[0031] The slope;

[0032] This is the intercept.

[0033] Specifically, the analysis auxiliary line P L With the hydrostatic pressure P 静水 The depth at the intersection is H, which represents the pre-drilling overpressure top surface depth of the exploration well. TOP .

[0034] Secondly, this invention discloses a device for predicting the depth of the overpressure top surface before drilling in an exploration well, comprising:

[0035] The first unit is used to collect formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points;

[0036] The second unit is used to obtain the density curves of exploration wells;

[0037] The third unit is used to calculate the overlying strata pressure P of the exploration well based on the density curve of the exploration well. O and the hydrostatic pressure P of the exploration well 静水 ;

[0038] The fourth unit is used to determine the overlying strata pressure P of the exploration well. O The hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP .

[0039] Thirdly, the present invention discloses a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described method.

[0040] Fourthly, the present invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] (I) This invention discloses a method for predicting the overpressure top depth before drilling exploration wells, comprising: collecting formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points; obtaining the density curve of the exploration well; and calculating the overlying strata pressure P of the exploration well based on the density curve of the exploration well. O and the hydrostatic pressure P of the exploration well 静水 According to the overlying strata pressure P of the exploration well O The hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP The method for predicting the overpressure top depth before drilling exploration wells disclosed in this invention utilizes the trend of density variation with burial depth and the formation pressure test data of drilled wells for analysis, avoiding the uncertainty caused by relying solely on formation velocity to predict the overpressure top depth, and improving the accuracy of overpressure top depth prediction before drilling exploration wells.

[0043] (II) This invention discloses a method for predicting the depth of the overpressure top surface before drilling in exploration wells. It is simple to operate and easy to implement. Moreover, the steps of the method are clear and the calculation process is relatively simple, which makes it easy to promote and apply in actual exploration work, thereby improving work efficiency and reducing drilling risks. As a new method, it can improve the accuracy of predicting the overpressure top surface before drilling in exploration wells. Attached Figure Description

[0044] Figure 1 The overlying strata pressure P of the exploration well provided in Embodiment 1 of the present invention is... O The hydrostatic pressure P of the exploration well 静水 Interaction graph of depth and pressure at multiple drilled formation pressure test points. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0046] To address the issues of high uncertainty and large prediction errors in the current prediction results of pre-drilling overpressure top surface depth for exploration wells, this invention discloses a method for predicting the pre-drilling overpressure top surface depth for exploration wells. The method includes: collecting formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points; obtaining the density curves of the exploration wells; and calculating the overlying strata pressure P of the exploration wells based on the density curves. O and the hydrostatic pressure P of the exploration well 静水 According to the overlying strata pressure P of the exploration well O The hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP The method for predicting the overpressure top surface depth before drilling in exploration wells disclosed in this invention improves the accuracy and reliability of overpressure top surface prediction before drilling in exploration wells, and provides a new method for predicting the overpressure top surface depth before drilling in the field of oil drilling.

[0047] Example 1: A method for predicting the depth of overpressure top surface before drilling in exploration wells

[0048] Example 1 provides a method for predicting the depth of the overpressure top surface before drilling in an exploration well, including the following steps:

[0049] Step a: Collect formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points;

[0050] Step b: Obtain the density curve of the exploration well, including the following steps:

[0051] Step b1: Collect density data of drilled wells in the study area;

[0052] Step b2: Establish a trend curve of density variation with burial depth in the study area based on the density data of the drilled wells in the study area;

[0053] Step b3: Obtain the density curve of the exploration well based on the trend curve of density variation with burial depth in the study area.

[0054] Step c: Calculate the overlying strata pressure P of the exploration well based on the density curve of the exploration well. O and the hydrostatic pressure P of the exploration well 静水 ;

[0055] Among them, the overlying strata pressure P of the exploration well O The calculation expression is:

[0056] (Equation 1)

[0057] In the formula, The depth of the overlying rock strata;

[0058] This represents the density at depth H of the overlying strata in the density curve of the exploration well.

[0059] The hydrostatic pressure P of the exploration well 静水 The calculation expression is:

[0060] (Equation 2)

[0061] In the formula, The depth of the overlying rock strata;

[0062] This represents the formation water density at depth H of the overlying strata in the density curve of the exploration well.

[0063] Specifically, In the implementation of a certain exploration well, 1 g / cm³ was taken. 3 .

[0064] Step d: Based on the overlying strata pressure P of the exploration well O The hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP This includes the following steps:

[0065] Step d1: The pressure P of the overlying strata of the exploration well O The hydrostatic pressure P of the exploration well 静水 The multiple drilled formation pressure test points are plotted in the same depth-pressure coordinate system to obtain the overlying strata pressure P of the exploration well. O The hydrostatic pressure P of the exploration well 静水 Interaction graphs of depth and pressure with multiple drilled formation pressure test points, such as... Figure 1 As shown.

[0066] Step d2: The pressure P of the overlying strata in the explored well O The hydrostatic pressure P of the exploration well 静水 Draw an analysis auxiliary line P on the depth-pressure interaction graph of multiple drilled formation pressure test points. L The analysis auxiliary line P L The pressure P of the overlying strata parallel or approximately parallel to the exploration well. O And it should pass through areas with a high density of drilled formation pressure test points as much as possible.

[0067] Wherein, the analysis auxiliary line P L Depth With pressure The relational expression is:

[0068] (Equation 3)

[0069] In the formula, For this analysis, the auxiliary line P L Depth above;

[0070] For this analysis, the auxiliary line P L Depth Pressure at the location;

[0071] The slope;

[0072] This is the intercept.

[0073] Specifically, in the implementation and application of a certain exploration well, Take 40, Take 800.

[0074] Step d3: Based on the analysis auxiliary line P L With hydrostatic pressure P 静水 The depth at the intersection point yields the pre-drilling overpressure top surface depth H of the exploration well. TOP .

[0075] Specifically, the analysis auxiliary line P L With the hydrostatic pressure P 静水 The depth at the intersection is H, which represents the pre-drilling overpressure top surface depth of the exploration well. TOP .

[0076] Specifically, in the implementation of a certain exploration well, the pre-drilling overpressure top surface depth H of the exploration well... TOP It is 1350m.

[0077] Example 2: A device for predicting overpressure top surface before drilling in exploration wells

[0078] Example 2 provides a device for predicting overpressure top surface before drilling in exploration wells, comprising:

[0079] The first unit is used to collect formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points;

[0080] The second unit is used to obtain the density curves of exploration wells;

[0081] The third unit is used to calculate the overlying strata pressure P of the exploration well based on the density curve of the exploration well. O and the hydrostatic pressure P of the exploration well 静水 ;

[0082] The fourth unit is used to determine the overlying strata pressure P of the exploration well. OThe hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP .

[0083] Example 3: A computer-readable storage medium

[0084] Example 3 provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method of Example 1.

[0085] Example 4: A computer device

[0086] Example 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 executes the computer program to implement the steps of the method of Example 1.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate 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 before drilling in an exploration well, characterized in that, include Step a: Collect formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points; Step b: Obtain the density curve of the exploration well; Step c: Calculate the overlying strata pressure P of the exploration well based on the density curve of the exploration well. O and the hydrostatic pressure P of the exploration well 静水 ; Step d: Based on the overlying strata pressure P of the exploration well O The hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP This includes the following steps: Step d1: The pressure P of the overlying strata of the exploration well O The hydrostatic pressure P of the exploration well 静水 The multiple drilled formation pressure test points are plotted in the same depth-pressure coordinate system to obtain the overlying strata pressure P of the exploration well. O The hydrostatic pressure P of the exploration well 静水 Interaction graph of depth and pressure with multiple drilled formation pressure test points; Step d2: The pressure P of the overlying strata in the explored well O The hydrostatic pressure P of the exploration well 静水 Draw an analysis auxiliary line P on the depth-pressure interaction graph of multiple drilled formation pressure test points. L The analysis auxiliary line P L The pressure P of the overlying strata parallel or approximately parallel to the exploration well. O And it should pass through areas with a high density of drilled formation pressure test points as much as possible; Step d3: Based on the analysis auxiliary line P L With hydrostatic pressure P 静水 The depth at the intersection point yields the pre-drilling overpressure top surface depth H of the exploration well. TOP .

2. The method for predicting the depth of the overpressure top surface before drilling in an exploration well according to claim 1, characterized in that, Obtaining the density curve of the exploration well includes the following steps: Collect density data of drilled wells in the study area; A trend curve of density variation with burial depth in the study area was established based on the density data of the drilled wells in the study area. Based on the trend curve of density variation with burial depth in the study area, the density curve of the exploration well is obtained.

3. The method for predicting the depth of the overpressure top surface before drilling in an exploration well according to claim 1, characterized in that, The overlying strata pressure P of the exploration well O The calculation expression is: (Equation 1) In the formula, The depth of the overlying rock strata; This represents the density at depth H of the overlying strata in the density curve of the exploration well.

4. The method for predicting the depth of the overpressure top surface before drilling in exploration wells according to claim 1, characterized in that... The hydrostatic pressure P of the exploration well 静水 The calculation expression is: (Equation 2) In the formula, The depth of the overlying rock strata; This represents the formation water density at depth H of the overlying strata in the density curve of the exploration well.

5. The method for predicting the depth of the overpressure top surface before drilling in an exploration well according to claim 1, characterized in that, The analysis auxiliary line P L Depth With pressure The relational expression is: (Equation 3) In the formula, For this analysis, the auxiliary line P L Depth above; For this analysis, the auxiliary line P L Depth Pressure at the location; The slope; This is the intercept.

6. A device for predicting the depth of overpressure top surface before drilling in an exploration well, characterized in that, include The first unit is used to collect formation pressure test data from drilled wells in the study area, including multiple drilled formation pressure test points; The second unit is used to obtain the density curves of exploration wells; The third unit is used to calculate the overlying strata pressure P of the exploration well based on the density curve of the exploration well. O and the hydrostatic pressure P of the exploration well 静水 ; The fourth unit is used to determine the overlying strata pressure P of the exploration well. O The hydrostatic pressure P of the exploration well 静水 Based on the aforementioned multiple drilled formation pressure test points, the pre-drilling overpressure top surface depth H of the exploration well was determined. TOP This includes the following steps: The pressure P of the overlying strata of the exploration well O The hydrostatic pressure P of the exploration well 静水 The multiple drilled formation pressure test points are plotted in the same depth-pressure coordinate system to obtain the overlying strata pressure P of the exploration well. O The hydrostatic pressure P of the exploration well 静水 Interaction graph of depth and pressure with multiple drilled formation pressure test points; The pressure P of the overlying strata above the exploration well O The hydrostatic pressure P of the exploration well 静水 Draw an analysis auxiliary line P on the depth-pressure interaction graph of multiple drilled formation pressure test points. L The analysis auxiliary line P L The pressure P of the overlying strata parallel or approximately parallel to the exploration well. O And it should pass through areas with a high density of drilled formation pressure test points as much as possible; Based on the analysis of auxiliary line P L With hydrostatic pressure P 静水 The depth at the intersection point yields the pre-drilling overpressure top surface depth H of the exploration well. TOP .

7. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the steps of the method described in any one of claims 1 to 5.

8. A computer device, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of the method according to any one of claims 1 to 5.

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