Deep stratum natural deflecting force evaluation method and device

Abstract

The invention relates to the technical field of oil and gas well engineering, in particular to a deep stratum natural deflecting force evaluation method and device.The method comprises the steps that micro-drill-bit drilling experiment data of outcrop rocks corresponding to an easily-deviated stratum when a target stratum is drilled is obtained; according to the micro drill bit drilling experiment data, based on a micro drill bit drilling speed equation, drilling speeds perpendicular to the layer and parallel to the layer are calculated; determining a stratum rock anisotropy characteristic index under the high-temperature and high-pressure environment according to the drilling speed perpendicular to the layer and the drilling speed parallel to the layer; and determining the natural deflecting force of the stratum according to the anisotropic characteristic index of the stratum rock. According to the method, the natural deflecting force of the deep stratum is rapidly and accurately obtained, the well track and the control track are efficiently designed, the drilling speed is increased, the well bore quality is improved, the drilling cost is reduced, and technical support is provided for deep oil-gas exploration and development.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well engineering technology, and is a method and device for evaluating the natural deviating force in deep formations. Background Technology

[0002] With the increasing demand for oil and gas resources year by year, the production of shallow and medium-depth oil and gas resources, which are easier to develop, is declining. Oil and gas exploration and development are shifting from shallow and medium-depth to deep and ultra-deep layers, from shallow and medium-deep seas to deep and ultra-deep seas, and from conventional to unconventional oil and gas. This has become an inevitable trend in global oil and gas exploration, especially with the broad prospects for deep and ultra-deep oil and gas development. In deep oil and gas exploration and development, steep structures or highly anisotropic formations are often encountered. These formations have high natural build-up characteristics, which can easily cause technical challenges such as well deviation. The natural build-up characteristics of formations are objective realities that can only be scientifically understood and effectively utilized. Studying the natural build-up force of formations is of great significance for preventing deviation in deep vertical wells, well trajectory design, and control. In terms of well trajectory design, three-dimensional trajectory design can be performed based on the natural build-up force of formations, thereby enabling drilling and target hitting using the natural build-up force of formations. Furthermore, understanding the natural build-up force of the formation allows for the design of reasonable lower drill string structures and drilling parameters. This enables the control of well inclination while significantly increasing the rate of drilling, improving wellbore quality, reducing drilling cycles, and enhancing the exploration and development efficiency of deep and ultra-deep wells. In terms of wellbore trajectory control, the natural build-up force of the formation is a crucial foundation for efficiently controlling wellbore inclination angles.

[0003] Current methods for evaluating the natural orogenic force in deep strata mainly rely on inversion from actual drilling data to estimate the natural geological patterns. However, inversion from actual drilling data cannot accurately calculate the natural orogenic force in steep tectonic strata. Furthermore, deep strata are situated in complex environments characterized by high temperature and pressure, and existing methods cannot accurately evaluate the natural orogenic force in anisotropic strata subjected to high temperature and pressure. Therefore, a comprehensive evaluation method for the natural orogenic force in deep strata has not yet been developed. Summary of the Invention

[0004] This invention provides a method for evaluating the natural orthotropic force in deep strata, which overcomes the shortcomings of the prior art and can effectively solve the problem that existing methods cannot accurately evaluate the natural orthotropic force in high-temperature and high-pressure anisotropic strata.

[0005] One of the technical solutions of this invention is achieved through the following measures: a method for evaluating the natural orthotropic force in deep strata, comprising:

[0006] Obtain micro-bit drilling experimental data of the outcrop rock corresponding to the easily inclined strata encountered during drilling in the target formation;

[0007] Based on the drilling experiment data of the micro-drill bit, the drilling speed perpendicular to and parallel to the plane was calculated according to the micro-drill bit drilling speed equation.

[0008] The anisotropy index of formation rocks under high temperature and high pressure environment is determined based on the drilling speed perpendicular to and parallel to the bedding plane.

[0009] The natural tilting force of strata is determined based on the anisotropic characteristic index of strata rocks.

[0010] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions:

[0011] The aforementioned micro-drilling experiment data includes micro-drilling experiment data parallel to and perpendicular to the bedding rock samples.

[0012] The above-mentioned micro-drilling experiment was an indoor high-temperature and high-pressure micro-drilling experiment. The experimental temperature environment was the same as the temperature measured near the drill bit while drilling in the target formation. The experimental pressure environment included formation pore pressure and confining pressure. The pore pressure was the same as the formation pore pressure measured near the drill bit while drilling in the target formation, and the confining pressure was the same as the formation confining pressure value corresponding to the well depth of the target formation.

[0013] The above micro-drill bit drilling speed equation is:

[0014]

[0015] In the formula, ROP v The drilling speed is perpendicular to the bedding direction, in mm / s; ROP p The drilling speed is parallel to the bedding direction, in mm / s; h s (t) represents the instantaneous advance of the initial segment, in mm; h e (t) represents the transient advance of the final segment, in mm; t sa The start time of drilling is s;t ea The drilling time is s; n is the number of data points in the initial segment, dimensionless; m is the number of data points in the final segment, dimensionless.

[0016] The above determination of the anisotropic characteristic index of formation rocks under high temperature and high pressure conditions based on drilling speeds perpendicular to and parallel to the bedding plane includes: determining the anisotropic characteristic index of formation rocks according to the following formula:

[0017]

[0018] In the formula, D H ROP is a dimensionless index representing the anisotropy characteristics of stratigraphic rocks. v The drilling speed is perpendicular to the bedding direction, in mm / s; ROP p The drilling speed is parallel to the bedding direction, in mm / s.

[0019] The above-mentioned determination of the natural orogenic force of strata based on the anisotropic characteristic index of strata rocks includes determining the natural orogenic force of strata according to the following formula:

[0020]

[0021] In the formula, F n The natural tilting force of the strata, N; D H α is the anisotropic characteristic index of the formation rocks, dimensionless; β is the formation dip angle, °; α is the well inclination angle near the drill bit during drilling, °; The drilling pressure is N.

[0022] The above also includes the natural orogenic force F of the strata. n The calculated values ​​are used to evaluate the natural orogenic force in deep strata, including:

[0023] F n If <0, then the natural orogenic force of the strata is the declination force;

[0024] F n If the value is greater than 0, then the natural orogenic force of the strata is the inclination-increasing force;

[0025] F n =0, then the natural orthotropic force of the strata does not exist.

[0026] The second technical solution of the present invention is achieved through the following measures: a device for evaluating the natural orogenic force of deep strata, comprising:

[0027] The data acquisition module obtains micro-drilling experimental data of outcrops of rocks corresponding to easily inclined strata encountered during drilling in the target formation.

[0028] The drilling speed module calculates the drilling speed perpendicular to and parallel to the bedding plane based on the drilling speed equation of the micro-drill bit and experimental data.

[0029] The characteristic index module determines the anisotropic characteristic index of formation rocks under high temperature and high pressure environment based on the drilling speed perpendicular to and parallel to the bedding plane.

[0030] The declination force determination module is used to determine the natural declination force of a stratum based on the anisotropic characteristic index of the strata rocks.

[0031] The following are further optimizations and / or improvements to the second technical solution of the above invention:

[0032] The aforementioned deep strata natural orogenic force evaluation device also includes:

[0033] The evaluation module assesses the natural orogenic force of deep strata based on the natural orogenic force, including:

[0034] F n If <0, then the natural orogenic force of the strata is the declination force;

[0035] F nIf the value is greater than 0, then the natural orogenic force of the strata is the inclination-increasing force;

[0036] F n =0, then the natural orthotropic force of the strata does not exist.

[0037] This invention provides a method for evaluating the natural build-up force in deep formations, enabling rapid and accurate acquisition of the natural build-up force in deep formations, efficient design of wellbore trajectories and control trajectories, improved drilling speed, improved wellbore quality and reduced drilling costs, providing technical support for deep oil and gas exploration and development. Attached Figure Description

[0038] Appendix Figure 1 This is a flowchart of Embodiment 10 of the present invention. Detailed Implementation

[0039] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0040] The present invention will be further described below with reference to embodiments:

[0041] Example 1: This method for evaluating the natural orogenic force in deep strata includes:

[0042] To obtain micro-bit drilling experimental data of the outcrops of rocks in the target formation when drilling encounters easily deviating formations (i.e., formations where wellbore deviation is likely to occur);

[0043] Based on the drilling experiment data of the micro-drill bit, the drilling speed perpendicular to and parallel to the plane was calculated according to the micro-drill bit drilling speed equation.

[0044] The anisotropy index of formation rocks under high temperature and high pressure environment is determined based on the drilling speed perpendicular to and parallel to the bedding plane.

[0045] The natural tilting force of strata is determined based on the anisotropic characteristic index of strata rocks.

[0046] Example 2: As an optimization of the above example, the micro-drilling experiment data includes micro-drilling experiment data parallel to and perpendicular to the bedding rock samples. Specifically, it includes data such as the transient footage in the initial segment, the transient footage in the final segment, the start time of drilling, the end time of drilling, the number of data points in the initial segment, and the number of data points in the final segment during the micro-drilling experiments parallel to and perpendicular to the bedding rock samples.

[0047] Example 3: As an optimization of the above example, the micro-drilling experiment is an indoor high-temperature and high-pressure micro-drilling experiment. The experimental temperature environment is the same as the temperature measured near the drill bit while drilling in the target formation. The experimental pressure environment includes formation pore pressure and confining pressure. The pore pressure is the same as the formation pore pressure measured near the drill bit while drilling in the target formation, and the confining pressure is the same as the formation confining pressure value corresponding to the well depth of the target formation.

[0048] In this invention, the specific operation of the indoor high temperature and high pressure micro drill bit drilling experiment can be referred to the literature "Suggestions on the improvement and optimization of rock drillability determination method" (Acta Petrolei Sinica, 2023, 44(09): 1562-1573).

[0049] Example 4: As an optimization of the above examples, the micro-drill bit drilling speed equation is as follows:

[0050]

[0051] In the formula, ROP v The drilling speed is perpendicular to the bedding direction, in mm / s; ROP p The drilling speed is parallel to the bedding direction, in mm / s; h s (t) represents the instantaneous advance of the initial segment, in mm; h e (t) represents the transient advance of the final segment, in mm; t sa The start time of drilling is s;t ea The drilling time is s; n is the number of data points in the initial segment, dimensionless; m is the number of data points in the final segment, dimensionless.

[0052] Example 5: As an optimization of the above embodiment, determining the anisotropic characteristic index of formation rocks under high temperature and high pressure conditions based on drilling speeds perpendicular to and parallel to the bedding plane includes: determining the anisotropic characteristic index of formation rocks according to the following formula:

[0053]

[0054] In the formula, D H ROP is a dimensionless index representing the anisotropy characteristics of stratigraphic rocks. v The drilling speed is perpendicular to the bedding direction, in mm / s; ROP p The drilling speed is parallel to the bedding direction, in mm / s.

[0055] Example 6: As an optimization of the above examples, the natural orogenic force of the formation is determined based on the anisotropic characteristic index of the formation rocks, including determining the natural orogenic force of the formation according to the following formula:

[0056]

[0057] In the formula, F nThe natural tilting force of the strata, N; D H β is the anisotropic characteristic index of the formation rocks, dimensionless; β is the formation dip angle, °; α is the near-bit borehole inclination angle during drilling, °; P B The drilling pressure is N.

[0058] Example 7: As an optimization of the above embodiment, it also includes adjusting the natural orogenic force F of the formation. n The calculated values ​​are used to evaluate the natural orogenic force in deep strata, including:

[0059] F n If <0, then the natural orogenic force of the strata is the declination force;

[0060] F n If the value is greater than 0, then the natural orogenic force of the strata is the inclination-increasing force;

[0061] F n =0, then the natural orthotropic force of the strata does not exist.

[0062] Example 8: This deep strata natural orogenic force evaluation device includes:

[0063] The data acquisition module obtains micro-drilling experimental data of outcrops of rocks corresponding to easily inclined strata encountered during drilling in the target formation.

[0064] The drilling speed module calculates the drilling speed perpendicular to and parallel to the bedding plane based on the drilling speed equation of the micro-drill bit and experimental data.

[0065] The characteristic index module determines the anisotropic characteristic index of formation rocks under high temperature and high pressure environment based on the drilling speed perpendicular to and parallel to the bedding plane.

[0066] The deflection force determination module is used to determine the natural deflection force of strata based on the anisotropic characteristic index of strata rocks;

[0067] Example 9: As an optimization of the above embodiments, the deep strata natural orogenic force evaluation device further includes:

[0068] The evaluation module assesses the natural orogenic force of deep strata based on the natural orogenic force, including:

[0069] F n If <0, then the natural orogenic force of the strata is the declination force;

[0070] F n If the value is greater than 0, then the natural orogenic force of the strata is the inclination-increasing force;

[0071] F n =0, then the natural orthotropic force of the strata does not exist.

[0072] Example 10: The specific implementation process of this method for evaluating the natural orthotropic force in deep strata is as follows:

[0073] Step 1: Obtain formation characteristics, wellbore trajectory survey data, and near-bit engineering parameters of drilled wells by collecting geological data and drilling data. The formation characteristics include formation dip and formation strike, the survey data includes well depth and well inclination angle, and the near-bit engineering parameters include drilling pressure, formation pore pressure, and formation temperature.

[0074] Step 2: Collect outcrop rocks corresponding to easily deviated formations encountered during drilling, and prepare rock samples required for the indoor high-temperature and high-pressure micro-drilling experiment. Conduct the high-temperature and high-pressure micro-drilling experiment and record the micro-drilling depth and time data. Two types of rock samples need to be prepared for the indoor high-temperature and high-pressure micro-drilling experiment: one parallel to the formation bedding angle and the other perpendicular to the formation bedding angle. The temperature environment for the high-temperature and high-pressure micro-drilling experiment is applied based on the temperature data measured near the drill bit in Step 1. The pressure environment includes formation pore pressure and confining pressure. The pore pressure is applied based on the formation pore pressure value measured near the drill bit in Step 1, and the confining pressure is applied based on the formation confining pressure value corresponding to the target formation depth in Step 1.

[0075] Step 3: Calculate the drilling speed based on the micro-drill bit drilling speed equations (Equations 1 and 2);

[0076] Step 4: Calculate the anisotropic characteristic index of the formation rocks under high temperature and high pressure based on the calculation equation (Equation 3).

[0077] Step 5: Calculate the natural formation force based on the natural formation force calculation equation (Equation 4), and evaluate the natural formation force of deep strata based on the calculated value of the natural formation force.

[0078] In summary, this invention provides a method for evaluating the natural build-up force in deep formations. This method considers the micro-drilling speed under high temperature and high pressure conditions in deep formations and defines the anisotropic characteristic index of the formation rock based on the micro-drilling speed in such conditions. Combined with actual drilling parameters, it accurately obtains the natural build-up force in deep formations. This invention solves the problem of accurately obtaining the natural build-up force in deep formations. Furthermore, this invention can be used for anti-deviation in deep vertical wells, and for the design and construction of various complex well structures such as directional wells, horizontal wells, and extended reach wells. It is applicable to various drilling methods such as sliding steerable, rotary steerable, and composite steerable drilling, and has broad application prospects.

[0079] The above technical features constitute the preferred embodiment of the present invention, which has strong adaptability and optimal implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A method for evaluating natural build-up of angle force in deep formations, characterized by The method comprises the following steps: obtaining micro-bit drilling experiment data of outcrop rock corresponding to a target stratum drilling encountered easy-inclined stratum; calculating drilling velocities perpendicular to and parallel to a stratum surface based on a micro-bit drilling velocity equation according to the micro-bit drilling experiment data; determining an anisotropy characteristic index of stratum rock in a high-temperature and high-pressure environment according to the drilling velocities perpendicular to and parallel to the stratum surface; determining a stratum natural build-up force according to the anisotropy characteristic index of the stratum rock.

2. The method of claim 1, wherein The micro-bit drilling experiment data includes micro-bit drilling experiment data of rock samples parallel to and perpendicular to stratum bedding.

3. The method of claim 1 or 2, wherein The micro-bit drilling experiment is a laboratory high-temperature and high-pressure micro-bit drilling experiment, the experimental temperature environment is the same as the temperature measured by the target stratum while drilling near the bit, and the experimental pressure environment includes stratum pore pressure and confining pressure, the pore pressure is the same as the stratum pore pressure measured by the target stratum while drilling near the bit, and the confining pressure is the same as the stratum confining pressure value corresponding to the target stratum well depth.

4. The method of claim 1-3, wherein The micro-bit drilling velocity equation is: where ROP v is the drilling rate perpendicular to the bedding direction, mm / s; ROP p is the drilling rate parallel to the bedding direction, mm / s; h s (t) is the initial transient footage, mm; h e (t) is the final transient footage, mm; t sa is the start drilling time, s; t ea is the end drilling time, s; n is the number of data points in the initial segment, dimensionless; m is the number of data points in the final segment, dimensionless.

5. The method of claim 1-4, wherein The determination of the anisotropy characteristic index of the stratum rock in the high-temperature and high-pressure environment according to the drilling velocities perpendicular to and parallel to the stratum surface comprises determining the anisotropy characteristic index of the stratum rock according to the following formula: wherein D H is the anisotropy index of the formation rock, dimensionless; ROP v is the drilling speed perpendicular to the bedding direction, mm / s; ROP p is the drilling speed parallel to the bedding direction, mm / s.

6. The method of claim 1-5, wherein The determination of the stratum natural build-up force according to the anisotropy characteristic index of the stratum rock comprises determining the stratum natural build-up force according to the following formula: where F n is the natural build-up force of the formation, N; D H is the anisotropy index of the formation rock, dimensionless β is the formation dip, °; a is the near-bit hole inclination while drilling, °; W is the weight on bit, N.

7. The method of claim 1-6, wherein Also included is the evaluation of the natural build-up of the deep formation according to the calculated value of the natural build-up force F n of the deep formation, including: F n If < 0, the natural build-up force of the formation is a drop-off force. F n If the value of the natural build-up angle is greater than 0, the natural build-up angle of the formation is a build-up angle. F n = 0, then the natural build-up of the formation does not exist.

8. A device for evaluating a natural build-up of a deep formation, which uses the method for evaluating a natural build-up of a deep formation according to any one of claims 1 to 7, characterized by The method comprises the following steps: a data acquisition module for obtaining micro-bit drilling experiment data of outcrop rock corresponding to a target stratum drilling encountered easy-inclined stratum; a drilling velocity module for calculating drilling velocities perpendicular to and parallel to a stratum surface based on a micro-bit drilling velocity equation according to the micro-bit drilling experiment data; a characteristic index module for determining an anisotropy characteristic index of stratum rock in a high-temperature and high-pressure environment according to the drilling velocities perpendicular to and parallel to the stratum surface; a build-up force determination module for determining a stratum natural build-up force according to the anisotropy characteristic index of the stratum rock.

9. The apparatus of claim 8, wherein The method further comprises the following steps: an evaluation module for evaluating a deep stratum natural build-up force according to the stratum natural build-up force, comprising: F n If < 0, the natural build-up force of the formation is a drop-off force. F n If the value of the natural build-up angle is greater than 0, the natural build-up angle of the formation is a build-up angle. F n = 0, then the natural build-up of the formation does not exist.

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