Wellbore trajectory identification method and device based on formation rock crushing specific work calculation

Abstract

The application discloses a wellbore trajectory identification method and device based on formation rock broken specific work calculation and belongs to the technical field of oil and gas drilling process. Firstly, formation rock drilling resistance characteristic experiment test is carried out to measure relevant parameters; rock broken specific work under drillability grade value measurement conditions is obtained respectively; a function relationship among logging data, drillability grade value and broken specific work is established; logging data is used to calculate formation rock broken specific work profile curve; real drilling broken specific work calculation model is directly derived and obtained profile curve according to drilling pressure, rotating speed, drilling time and drill bit diameter information in real drilling data; correlation analysis is carried out according to the profile curves obtained by the two broken specific work calculation models; formation rock drilling resistance strength test and broken specific work profile analysis method are tested; and similarity principle is used to extract similarity index parameters through the curves, and then the conformity degree of the drilling trajectory is judged. The application realizes effective plugging of old wellbores and is suitable for popularization and application.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling technology, and specifically to a wellbore trajectory identification method based on formation rock fracturing specific work calculation. Background Technology

[0002] my country is a major natural gas reserve holder and a major natural gas consumer, especially with the rapid growth in natural gas consumption due to the construction of large long-distance pipelines such as the West-East Gas Pipeline I and II. my country needs to import and store large quantities of natural gas. Currently, natural gas is mainly stored in two forms: gaseous storage and liquid storage. The former includes surface tank storage, pipeline storage, and underground gas storage tanks. Surface gas storage can only be used to eliminate the uneven distribution of gas demand between day and night, and its high cost and complex operation are not conducive to long-term storage. The fundamental solution to the problem of uneven seasonal gas demand and long-term gas storage is to build underground gas storage facilities. my country's gas storage facilities are mainly gas reservoir type, primarily converted from depleted oil and gas fields. Currently, some areas awaiting construction or selected for storage facilities still have complex abandoned old wells that need priority treatment. For example, in storage areas such as Jilin and Dagang, some old wells have gas-bearing sections without casing sealing, and open-hole sections have penetrated the upper caprock of the gas reservoir, damaging the caprock's sealing. The effective treatment of these wells is crucial to the feasibility of building gas storage facilities.

[0003] These open-hole wells require re-drilling and then sealing the original wellbore. Accurately determining whether the drilled well's trajectory matches that of an old well is crucial during the drilling process. There is an urgent need for a practical technical method for identifying the trajectory of a new wellbore drilled from an old well. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems in the prior art and to provide a wellbore trajectory identification method and device based on formation rock fracture specific work calculation.

[0005] To address the aforementioned technical problems, in one aspect, embodiments of the present invention provide a wellbore trajectory identification method based on formation rock fracturing specific work calculation, comprising the following steps:

[0006] Step 1: Conduct drill resistance tests on the formation rocks and determine relevant parameters;

[0007] Step 2: Obtain the rock breaking specific work under the conditions of drilling grade determination;

[0008] Step 3: Establish the functional relationship between the three based on well logging data, drillability grade value, and fracture specific power;

[0009] Step 4: Calculate the formation rock fracturing specific work profile curve using well logging data;

[0010] Step 5: Based on the information such as drilling pressure, rotation speed, drilling time, and drill bit diameter in the actual drilling data, directly derive the actual drilling breakage specific work calculation model and obtain the profile curve;

[0011] Step 6: Perform correlation analysis on the profile curves obtained from the two crushing specific work calculation models;

[0012] Step 7: Verify the method of "testing the drilling resistance of formation rocks and analyzing the specific work of fracturing".

[0013] Step 8: Using the principle of similarity, extract similarity index parameters through curves to determine the degree of conformity of the drilling trajectory.

[0014] Furthermore, in step 1, the relevant parameters include compressive strength and drillability rating.

[0015] Furthermore, in step 6, the two specific models for calculating the specific work of crushing are as follows:

[0016] ① The model for calculating the specific work of formation rock fracturing based on actual drilling data is expressed as follows:

[0017]

[0018] in:

[0019] i D - Breaking specific work calculated based on actual drilling data;

[0020] C - constant; t - drilling time, min / m;

[0021] p - drilling pressure, kN; D h - Drill bit diameter, mm;

[0022] n - Rotational speed, r / min; V - Rock-breaking volume, m 3 ;

[0023] ②Based on the principle of drillability rating testing, the method for calculating the breaking specific work based on drillability determination is expressed as follows:

[0024]

[0025] in:

[0026] i Kd - Breaking specific work based on drillability determination;

[0027] Δh -- Drilling depth;

[0028] Kd - Drillability grade; T(t) - Torque as a function of time;

[0029] π - Pi (the mathematical constant in Chinese); t - drilling time

[0030] Furthermore, in step 7, the verification of the "drill resistance test and fracture specific energy profile analysis of formation rock" method specifically involves: establishing the two fracture specific energy evaluation methods mentioned above, respectively, to calculate the fracture specific energy under the original state, and using the "mean square error" of the deviation between the two as the similarity to establish the correlation between the two as the evaluation index; this can be expressed as:

[0031]

[0032] in:

[0033] σ - mean square deviation;

[0034] -Average;

[0035] σ D - Drillability extreme values ​​calculated from actual drilling data;

[0036] σ kd - Drillability extreme values ​​obtained from well logging data analysis.

[0037] Furthermore, in step 8, the specific steps of using the similarity principle to extract similarity index parameters through curves and then determining the degree of conformity of the drilling trajectory are as follows: Set C... p The value is a threshold for judging the degree of deviation, obtained through actual working conditions. Within a certain formation range, σ > C. p This represents the differences in wellbore characteristics, where σ≤C p This indicates that the wellbore diameters are the same. (C) p - Threshold for judging the degree of deviation.

[0038] On the other hand, embodiments of the present invention also provide a wellbore trajectory identification device based on formation rock fracturing specific work calculation, comprising:

[0039] The parameter measurement module is used to conduct experimental tests on the drill resistance characteristics of formation rocks and measure relevant parameters.

[0040] The rock breaking specific work measurement module is used to obtain the rock breaking specific work under the conditions of drilling grade value measurement.

[0041] The function relationship establishment module is used to establish the function relationship between logging data, drillability grade value and fracture specific power.

[0042] The profile curve calculation module uses well logging data to calculate the formation rock fracture specific work profile curve;

[0043] The profile curve acquisition module is used to directly derive the actual drilling breakage specific power calculation model and obtain the profile curve based on information such as drilling pressure, rotation speed, drilling time, and drill bit diameter in actual drilling data.

[0044] The correlation analysis module is used to perform correlation analysis based on the profile curves obtained from the two crushing specific work calculation models;

[0045] The verification module is used to verify the method of "testing the drilling resistance strength of formation rocks and analyzing the specific work of fracture".

[0046] The conformity assessment module uses the principle of similarity to extract similarity index parameters from curves, thereby determining the degree of conformity of the drilling trajectory.

[0047] On the other hand, embodiments of the present invention also provide a wellbore trajectory recognition system based on formation rock fracturing specific work calculation, including one or more processors; a memory for storing one or more programs; the processors are configured to execute program instructions stored in the memory, and the program instructions execute the above-described wellbore trajectory recognition method based on formation rock fracturing specific work calculation when they are executed.

[0048] On the other hand, embodiments of the present invention also provide a computer-readable storage medium storing a computer program, wherein the computer program, when executed by one or more processors, implements the above-described wellbore trajectory recognition method based on formation rock fracture specific work calculation.

[0049] The above-described technical solutions of the embodiments of the present invention have the following beneficial technical effects:

[0050] The technical solution of this invention can be used for the identification of new drilling trajectory in old wells, greatly reducing the drilling difficulty of exploration in old wells, providing a reference for drilling process adjustment, and ultimately achieving effective sealing of old wells, making it suitable for widespread application. Attached Figure Description

[0051] Figure 1 This is a flowchart illustrating the wellbore trajectory identification method based on formation rock fracturing specific work calculation of the present invention.

[0052] Figure 2 This is a schematic diagram of a drillable PDC micro drill bit;

[0053] Figure 3 It is the correlation fitting curve of formation "sonic transit time - drillability grade value";

[0054] Figure 4 It is a profile curve of the formation's drill resistance characteristics; among which, Figure 4 A is the sound wave time difference curve. Figure 4 B is the drillability grade value curve. Figure 4 C is the drilling parameter curve;

[0055] Figure 5A comparison of two fracture specific work profile curves in Well Xing 106;

[0056] Figure 6 These are two similarity evaluation curves for the specific work of breaking. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0058] Please refer to Figure 1 This invention provides a wellbore trajectory identification method based on formation rock fracturing specific work calculation, comprising the following steps:

[0059] Step 1: Conduct drill resistance tests on the formation rocks and determine relevant parameters;

[0060] Step 2: Obtain the rock breaking specific work under the conditions of drilling grade determination;

[0061] Step 3: Establish the functional relationship between the three based on well logging data, drillability grade value, and fracture specific power;

[0062] Step 4: Calculate the formation rock fracturing specific work profile curve using well logging data;

[0063] Step 5: Based on the information such as drilling pressure, rotation speed, drilling time, and drill bit diameter in the actual drilling data, directly derive the actual drilling breakage specific work calculation model and obtain the profile curve;

[0064] Step 6: Perform correlation analysis on the profile curves obtained from the two crushing specific work calculation models;

[0065] Step 7: Verify the method of "Drill Resistance Test and Fracture Specific Energy Profile Analysis of Formation Rocks"; Verification Module

[0066] Step 8: Using the principle of similarity, extract similarity index parameters through curves to determine the degree of conformity of the drilling trajectory.

[0067] Example 1

[0068] 1) Conduct drilling resistance tests on the formation rocks and determine parameters such as compressive strength and drillability grade.

[0069] 2) Obtain the rock breaking specific work under the conditions of drilling grade determination;

[0070] 3) Establish the functional relationship between the three based on well logging data, drillability grade value, and fracture specific power;

[0071] Standard rock cores were prepared according to the petroleum industry standard SY / T 5426-2016 (Test Method for Rock Drillability). A drillable PDC micro-drill bit with an outer diameter of 32mm, containing two 13.3mm × 4.5mm PDC composite plates, a back angle of 20°, and a side angle of 15° was used. Figure 2 As shown, the drillable PDC micro-drill bit includes a PDC composite plate 1, an internal hex screw 2, a clamping plate 3, and a drill body 4. The clamping plate 3 symmetrically clamps the two composite plates 1 onto the drill body 4, and fixes them with the internal hex screws 2. The drilling parameters are changed to: drilling pressure 500N; rotation speed 55r / min; drilling depth 3.0mm; pre-drilling depth 1.0mm. When the micro-drill bit is drilling, the drilling time (s) at a drilling depth of 3mm is recorded, and then converted into a logarithm based on base 2 to represent the drillability grade value.

[0072] That is: K d =log2t:

[0073] In the formula:

[0074] K d - Drillability rating; t - Average drilling time, seconds.

[0075] Based on the given well logging data, core formation data, and field measurement results, establish as follows: Figure 3 The correlation fitting curve data model of "sonic transit time - drillability grade value" is shown, and the formula is derived to establish the formation drillability profile curve of the target well.

[0076] Based on the above model and the derived formula, using the target well's logging data, drilling parameters, and other information, the following calculations are performed: Figure 4 The correlation curves of formation drill resistance characteristics are shown. Figure 4 From left to right Figure 4 A to Figure 4 The three curves (C) represent the sonic transit time curve of measured well logging data, the drillability calculation profile curve, and the actual drilling data (drilling pressure, rotation speed, and drilling time) profile curve, respectively.

[0077] Example 2

[0078] 4) Calculate the formation rock fracturing specific work profile curve using well logging data;

[0079] 5) Based on the information such as drilling pressure, rotation speed, drilling time, and drill bit diameter in the actual drilling data, the calculation model for the specific energy of actual drilling breakup is directly derived and the profile curve is obtained.

[0080] 6) Conduct correlation analysis based on the profile curves obtained from the two crushing specific work calculation models;

[0081] By combining the formation's drill resistance profile data with the two breakup specific work calculation formulas described in claim 1, it is possible to achieve the following: Figure 5 The figure shown is a comparison between the breakage specific energy profile curve based on drillability test and the breakage specific energy profile curve based on actual drilling data.

[0082] Example 3

[0083] 7) Verify the method of "testing the drilling resistance strength of formation rocks and analyzing the specific work of fracturing".

[0084] 8) Utilize the principle of similarity to extract similarity index parameters from curves, and then determine the degree of conformity of the drilling trajectory.

[0085] Using the two calculated specific energy profile curves of crushing, and combining them with the evaluation method proposed in claim 1, the following formula can be used to obtain: Figure 6 The evaluation curve shown, combined with the actual working conditions, determines the "threshold line Cp" and marks it on the evaluation curve. This is used to judge the degree of compliance of the breaking specific work. If the evaluation coefficient is closer to the "threshold line Cp", the drilled well trajectory can be approximately considered as the old well trajectory. Conversely, if it is closer to the "threshold line Cp", the drilled well trajectory is judged not to be the old well trajectory. The wells drilled according to this standard can meet the requirements.

[0086] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A wellbore trajectory recognition method based on formation rock fracturing specific work calculation, characterized in that, Includes the following steps: Step 1: Conduct drill resistance tests on the formation rocks and determine relevant parameters; Step 2: Obtain the rock breaking specific work under the conditions of drilling grade determination; Step 3: Establish the functional relationship between the three based on well logging data, drillability grade value, and fracture specific power; Step 4: Calculate the formation rock fracturing specific work profile curve using well logging data; Step 5: Based on the drilling pressure, rotation speed, drilling time, and drill bit diameter information in the actual drilling data, directly derive the actual drilling breakage specific work calculation model and obtain the profile curve; Step 6: Perform correlation analysis on the profile curves obtained from the two crushing specific energy calculation models. The two crushing specific energy calculation models are as follows: ① The model for calculating the specific work of formation rock fracturing based on actual drilling data is expressed as follows: in: i D - Breaking specific work calculated based on actual drilling data; C - constant; t - drilling time, min / m; P - Drilling pressure, kN; Dh - Drill bit diameter, mm; n - Rotational speed, r / min; V - Rock-breaking volume, m³ 3 ; ②Based on the principle of drillability rating testing, the method for calculating the breaking specific work based on drillability determination is expressed as follows: in: i Kd - Breaking specific work based on drillability determination; Δh - Drilling depth; Kd - Drillability rating; T(t) - Torque as a function of time π - Pi (the mathematical constant in Chinese); t - drilling time; Step 7: Verify the methods for testing the drilling resistance strength of formation rocks and analyzing the specific work ratio of fractured rock. Step 8: Using the principle of similarity, extract similarity index parameters through curves to determine the degree of conformity of the drilling trajectory.

2. The wellbore trajectory recognition method based on formation rock fracturing specific work calculation according to claim 1, characterized in that, In step 1, the relevant parameters include compressive strength and drillability rating.

3. The wellbore trajectory recognition method based on formation rock fracturing specific work calculation according to claim 1, characterized in that, In step 7, the verification of the methods for testing the drilling resistance strength of formation rocks and analyzing the specific energy profile of rock breaking is specifically as follows: Two methods for evaluating specific energy breaking are established to calculate the specific energy breaking under the original conditions. The mean square error of the deviation between the two methods is used as the similarity to establish the correlation between them as an evaluation index; expressed as: in: σ - mean square deviation; , -Average; i D - Breaking specific work calculated based on actual drilling data; i Kd - Breaking specific work based on drillability determination.

4. The wellbore trajectory recognition method based on formation rock fracturing specific work calculation according to claim 1, characterized in that, In step 8, the specific steps of using the similarity principle to extract similarity index parameters through curves and then determining the degree of conformity of the drilling trajectory are as follows: Set C... p The value is a threshold for judging the degree of deviation, obtained through actual working conditions. Within a certain formation range, σ > C. p This represents the differences in wellbore characteristics, where σ≤C p This indicates that the wellbore diameters are the same, C p - Threshold for judging the degree of deviation.

5. A wellbore trajectory recognition device based on formation rock fracturing specific work calculation, characterized in that, include: The parameter measurement module is used to conduct experimental tests on the drill resistance characteristics of formation rocks and measure relevant parameters. The rock breaking specific work measurement module is used to obtain the rock breaking specific work under the conditions of drilling grade value measurement. The function relationship establishment module is used to establish the function relationship between logging data, drillability grade value and fracture specific power. The profile curve calculation module uses well logging data to calculate the formation rock fracture specific work profile curve; The profile curve acquisition module is used to directly derive the actual drilling breakage specific power calculation model and obtain the profile curve based on the information of drilling pressure, rotation speed, drilling time and drill bit diameter in the actual drilling data; The correlation analysis module is used to perform correlation analysis on the profile curves obtained from the two crushing specific energy calculation models. The two crushing specific energy calculation models are as follows: ① The model for calculating the specific work of formation rock fracturing based on actual drilling data is expressed as follows: in: i D - Breaking specific work calculated based on actual drilling data; C - constant; t - drilling time, min / m; P - Drilling pressure, kN; Dh - Drill bit diameter, mm; n - Rotational speed, r / min; V - Rock-breaking volume, m³ 3 ; ②Based on the principle of drillability rating testing, the method for calculating the breaking specific work based on drillability determination is expressed as follows: in: i Kd - Breaking specific work based on drillability determination; Δh - Drilling depth; Kd - Drillability rating; T(t) - Torque as a function of time π - Pi (the mathematical constant in Chinese); t - drilling time; The inspection module is used to inspect the drilling resistance strength test and the fracture specific work profile analysis method of the formation rock; The conformity assessment module uses the principle of similarity to extract similarity index parameters from curves, thereby determining the degree of conformity of the drilling trajectory.

6. A wellbore trajectory recognition system based on formation rock fracturing specific work calculation, characterized in that, Includes one or more processors; A memory for storing one or more programs; the processor is configured to execute program instructions stored in the memory, which, when executed, perform the wellbore trajectory recognition method based on formation rock fracturing specific work calculation as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein the computer program, when executed by one or more processors, implements the wellbore trajectory recognition method based on formation rock fracturing specific work calculation as described in any one of claims 1 to 4.

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