Method and device for determining equivalent impact torque of drill collar joint in downhole and storage medium

Abstract

The present application relates to a kind of drill collar joint downhole equivalent impact torque determination method, device and storage medium, by the method of field measurement and finite element model, to the drill collar joint field notch of completion upper buckle, after drilling, normal drilling, after tripping, measure drill collar joint male buckle, female buckle relative offset;And establish drill collar joint three-dimensional elastic-plastic finite element model, determine the relationship curve of drill collar joint male buckle, female buckle relative offset and applied torque, then according to the field measurement result determined to obtain the equivalent impact torque of downhole drill collar joint.The method provided by the present application can obtain more accurate downhole equivalent impact torque, provide basis for field operation, better guide field production.

Description

Technical Field

[0001] This invention relates to the field of oilfield drilling technology, and in particular to a method for determining the equivalent impact torque of a downhole drill collar joint. Background Technology

[0002] As oil and gas extraction depths increase, drilling conditions become harsher, with various phenomena such as stuck pipe, breakage, and corrosion occurring frequently, affecting the service life of downhole drilling tools and increasing drilling costs. The drill collar, located at the end of the drill string, is subjected to dynamic loads during drilling, rotating and breaking rock cuttings and gravel. It is subjected to complex alternating tensile, compressive, torsional, and bending loads, making it highly susceptible to failure in the complex downhole environment.

[0003] Practice shows that downhole drill collars are subjected to impact torque, causing secondary threading of the joints. However, the downhole impact torque is difficult to determine. Currently, numerical simulation and field testing are mainly used to understand the actual stress state of the drill string downhole, but how to measure the magnitude of the downhole impact torque has not yet been reported. Determining the downhole impact torque would have a significant impact on determining the working condition of the drill collars and improving drilling safety. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art and provide a method, device and storage medium for determining the downhole equivalent impact torque of a drill collar joint.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] As a first aspect of the present invention, a method for determining the downhole equivalent impact torque of a drill collar joint is provided, the method comprising the following steps:

[0007] Based on the three-dimensional elastoplastic finite element method, a model is determined to determine the relationship between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads under the action of the upper thread torque, axial compressive load and downhole impact torque.

[0008] Obtain the measured relative offset of the male and female threads of the drill collar joint after the drill is pulled out on site;

[0009] Based on the established relationship model between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads, as well as the measured relative offset of the male and female threads of the drill collar joint, the equivalent impact torque value of the downhole drill collar joint is obtained.

[0010] Furthermore, the steps for establishing the relationship model between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads are as follows:

[0011] Measure the geometric parameters of the drill collar joint, test the stress-strain relationship of the drill collar joint material, and the plastic strain at material failure.

[0012] Establish a three-dimensional elastoplastic finite element model of the drill collar joint;

[0013] Based on the established three-dimensional elastoplastic finite element model of the drill collar joint, the downhole working torque was applied to the drill collar joint under the action of the upper thread torque and axial compressive load, and the regular curve between the offset distance of the male and female threads of the drill collar joint and the working torque was determined.

[0014] By performing polynomial fitting on the regular curves of the offset distance between the male and female threads of the drill collar joint and the working torque, a relationship model between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads is obtained.

[0015] Furthermore, the three-dimensional elastoplastic finite element model of the drill collar joint includes the helix angle feature of the thread, the thread end feature, and the shoulder chamfer feature.

[0016] Furthermore, the specific steps for obtaining the measured relative offset of the male and female threads of the drill collar joint after on-site tripping are as follows:

[0017] Determine the torque value for the drill collar joint according to API standards, and complete the pre-tightening of the drill collar joint.

[0018] Before drilling, mark the male and female threads of the drill collar threaded joint as a marker;

[0019] After the drill collar joint with the marked notches is lowered into the well, normal drilling begins. After the drill string is pulled out, the relative offset of the male and female notches is measured.

[0020] As a second aspect of the present invention, a device for determining the downhole equivalent impact torque of a drill collar joint is provided, comprising a memory, a processor, and a program stored in the memory, wherein the processor executes the program to implement the downhole equivalent impact torque determination method of the drill collar joint as described above.

[0021] As a third aspect of the invention, a storage medium is provided on which a program is stored, which, when executed, implements the method for determining the downhole equivalent impact torque of the drill collar joint as described above.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) This invention provides a method for determining the impact torque of a downhole drill collar joint. By combining the three-dimensional finite element method and field measurement results, a more accurate downhole equivalent impact torque is obtained, providing a basis for field operations and better guiding field production.

[0024] 2) This invention provides a method for determining the equivalent impact torque of a downhole drill collar joint, which can determine the downhole equivalent impact torque of any currently used drill collar joint. Attached Figure Description

[0025] Figure 1 This is a flowchart of a method for determining the equivalent downhole impact torque of a drill collar joint according to the present invention;

[0026] Figure 2 This is a schematic diagram of a three-dimensional finite element model of a drill collar joint;

[0027] Figure 3 It is the curve showing the relationship between the downhole equivalent impact torque and the offset of the drill collar joint. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0029] Example 1

[0030] This invention combines on-site measurement with finite element analysis. First, the drill collar joint with the upper thread is scored on-site. After drilling, normal drilling is carried out. After tripping out, the relative offset of the male and female threads of the drill collar joint is measured. Then, a three-dimensional elastoplastic finite element model of the drill collar joint is established to determine the mechanical properties of the drill collar joint under complex loads such as upper thread torque, axial compressive load, and downhole impact torque. Combined with the on-site measurement results, the equivalent downhole impact torque is determined, which is the working torque equivalent to the effect of downhole impact torque.

[0031] like Figure 1 As shown, the determination of the equivalent impact torque of the downhole drill collar joint includes the following process:

[0032] 1) Use specialized tools to measure the geometric parameters of the drill collar joint, including the outer diameter, inner diameter, thread parameters, as well as the diameter of the female thread boring hole, the diameter of the male thread large end, the length of the female thread tapered section, and the length of the male thread tapered section, etc.

[0033] 2) Complete the pre-tightening of the drill collar joint according to API standards;

[0034] 3) Before drilling, use a specific tool to mark the male and female threads of the drill collar threaded joint. The marks should be located at the chamfer of the male and female threads shoulder, with a length of 5-15mm and a depth of 1-2mm.

[0035] 4) Run the drill collar joint with the marked marks into the well and drill normally. After pulling out the drill string, measure the relative offset of the male and female thread marks.

[0036] 5) Use material performance testing equipment to test the stress-strain relationship of the joint material and the plastic strain at material failure;

[0037] 6) Establish a three-dimensional elastoplastic finite element model of the drill collar joint, including the helix angle characteristics of the thread, the thread end characteristics, and the shoulder chamfer characteristics, etc.

[0038] 7) Apply downhole working torque to the drill collar joint under the action of upper torque and axial compressive load, and determine the regular curve between the offset distance of the male and female threads of the drill collar joint and the working torque;

[0039] 8) Perform polynomial fitting on the regular curves between the offset distance of the male and female threads of the drill collar joint and the working torque to obtain the relationship model between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads;

[0040] 9) Based on the actual relative offset of the male and female thread marks of the drill collar joint after tripping out of the well, determine the equivalent impact torque value of the drill collar joint downhole based on the above relationship model.

[0041] Example 2

[0042] This embodiment provides an implementation example of using the impact torque determination method of the present invention to determine the downhole equivalent impact torque of a certain 8″ drill collar joint.

[0043] The downhole equivalent impact torque of the drill collar joint in a well in a western oilfield of my country was determined using this impact torque determination method. The drill string assembly for this well was: 17″ PDC + 730*730 vertical drill + 731*731 + 730*NC770 screw + NC771*NC610 + NC61 reverse reamer stabilizer + 3 nine-inch drill collars + 3 NC611*NC560 + 13 eight-inch float valves + 13 eight-inch drill collars + 18-inch quake pump while drilling + 8-inch flexible joint + 5 eight-inch drill collars + 5 NC561*520 + 5 seven / eight-inch heavy-duty drill pipes.

[0044] 1) Use special tools to measure the geometric parameters of the drill collar joint, including the outer diameter, inner diameter, thread parameters, as well as the diameter of the female thread boring hole, the diameter of the male thread large end, the length of the female thread tapered part, and the length of the male thread tapered part, as shown in Table 1;

[0045] Table 1 Basic Dimensions of Drill Collar Joints

[0046] Inner diameter / mm 71.4 Buckle type V0.038R Male thread large end diameter / mm 149.2 Female thread boring hole diameter / mm 150.8 Male taper length / mm 127.0 Length of female buckle cone / mm 142.9

[0047] 2) Determine the torque value for the drill collar joint according to the API standard, and use B-type pliers or a drill bit to pre-tighten the drill collar joint.

[0048] 3) Before drilling, use a specific tool to mark the male and female threads of the drill collar threaded joint. The marks should be located at the chamfer of the male and female threads' shoulders, with a length of 10mm and a depth of 2mm. Figure 1 As shown.

[0049] 4) After marking the drill collar connector with notches, normal drilling commenced. Upon tripping out, it was found that the offset at the shoulder of the adapter connector and the 8″ float valve connector was 13mm, and the offset at the shoulder of the 8″ float valve and the 8″ drill collar connector was 4mm, as shown in Table 2. Figure 2 As shown.

[0050] Table 2 Experimental data of the second drilling stage of a certain well

[0051]

[0052]

[0053] 5) The stress-strain relationship of the joint material and the plastic strain at material failure were tested using material performance testing equipment, as shown in Table 3.

[0054] Table 3. True Stress-Plastic Strain Relationship

[0055] 758.0 0 953.7 0.025 1063.6 0.065 790.1 0.0005 971.3 0.030 1072.4 0.070 818.3 0.001 987.6 0.035 1079.8 0.075 878.5 0.006 1003.3 0.040 1086.1 0.080 891.3 0.009 1017.6 0.045 1091.2 0.085 905.2 0.012 1030.9 0.050 1095.1 0.097 920.8 0.016 1043.0 0.055 940.1 0.021 1054.3 0.060

[0056] 6) Establish a three-dimensional elastoplastic finite element model of the 8″ drill collar joint, including the helix angle characteristics of the thread, the thread end characteristics, the shoulder chamfer characteristics, etc. Figure 3 As shown;

[0057] 7) By applying a working torque to the drill collar joint under the action of the upper torque and axial compressive load, the offset distance of the male and female threads of the drill collar joint and the downhole impact torque curve can be determined, such as... Figure 3 As shown;

[0058] 8) Polynomial fitting was performed on the correlation curves between the offset distance of the male and female threads of the drill collar joint and the working torque to obtain the relationship model between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads:

[0059] L = -1.761e-05T 4 +0.006264T 3 -0.7941T 2 +43.34T-868.1(T≥66.3) (1)

[0060] In the formula, L is the circumferential offset distance of the drill collar joint at the shoulder of the male and female threads during drilling, in mm; T is the downhole impact torque value of the drill collar joint, in kN·m;

[0061] 9) Based on the actual relative offset of the male and female threads of the drill collar joint after tripping the drill string and Equation (1), the equivalent impact torque value of the drill collar joint downhole when the relative offset of the male and female threads is 13 mm is determined to be 91.3 kN·m. The on-site uncoupling torque of the joint is 90 kN·m. That is, the error between the equivalent impact torque value determined according to the present invention and the measured result is only 1.5%. When the relative offset of the male and female threads is 4 mm, the equivalent impact torque value of the drill collar joint downhole is 82.5 kN·m. That is, the error between the equivalent impact torque value determined according to the present invention and the measured result is only 3.2%.

[0062] Example 3

[0063] As a second aspect of the present invention, this application also provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; and, when the one or more programs are executed by the one or more processors, causing the one or more processors to implement the method for determining the equivalent downhole impact torque of a drill collar joint as described above. In addition to the processors, memory, and interface described above, any data processing device in the embodiments may also include other hardware depending on the actual function of the data processing device, which will not be elaborated further.

[0064] Example 4

[0065] As a third aspect of the present invention, this application also provides a computer-readable storage medium storing computer instructions thereon, which, when executed by a processor, implement the method for determining the equivalent downhole impact torque of a drill collar joint as described above. The computer-readable storage medium can be an internal storage unit of any data processing device as described in any of the foregoing embodiments, such as a hard disk or memory. The computer-readable storage medium can also be an external storage device, such as a plug-in hard disk, smart media card (SMC), SD card, flash card, etc., equipped on the device. Furthermore, the computer-readable storage medium can include both internal storage units of any data processing device and external storage devices. The computer-readable storage medium is used to store the computer program and other programs and data required by the data processing device, and can also be used to temporarily store data that has been output or will be output.

[0066] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for determining the equivalent downhole impact torque of a drill collar joint, characterized in that, The method steps include: Based on the three-dimensional elastoplastic finite element method, a relationship model was determined between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads under the action of top torque, axial compressive load, and downhole impact torque. The specific steps for establishing the relationship model are as follows: Measure the geometric parameters of the drill collar joint, test the stress-strain relationship of the drill collar joint material, and the plastic strain at material failure. Establish a three-dimensional elastoplastic finite element model of the drill collar joint; Based on the established three-dimensional elastoplastic finite element model of the drill collar joint, the downhole working torque was applied to the drill collar joint subjected to the upper torque and axial compressive load, and the regular curve between the offset distance of the male and female threads of the drill collar joint and the working torque was determined. Polynomial fitting was performed on the regular curves between the offset distance of the male and female threads of the drill collar joint and the working torque to obtain the relationship model between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads. The specific steps for obtaining the measured relative offset of the male and female threads of the drill collar joint after on-site tripping are as follows: Determine the torque value for the drill collar joint according to API standards, and complete the pre-tightening of the drill collar joint. Before drilling, mark the male and female threads of the drill collar threaded joint as a marker; After the drill collar joint with the marked marks is lowered into the well, drilling proceeds normally. After the drill string is pulled out, the relative offset of the male and female thread marks is measured. Based on the established relationship model between the equivalent downhole impact torque of the drill collar joint and the relative offset of the male and female threads, as well as the measured relative offset of the male and female threads of the drill collar joint, the equivalent impact torque value of the downhole drill collar joint is obtained.

2. The method for determining the equivalent downhole impact torque of a drill collar joint according to claim 1, characterized in that, The three-dimensional elastoplastic finite element model of the drill collar joint includes the helix angle feature of the thread, the thread end feature, and the shoulder chamfer feature.

3. A device for determining the equivalent impact torque of a drill collar joint in downhole drilling, comprising a memory, a processor, and a program stored in the memory, characterized in that, When the processor executes the program, it implements the method for determining the downhole equivalent impact torque of the drill collar joint as described in any one of claims 1-2.

4. A storage medium having a program stored thereon, characterized in that, When the program is executed, it implements the method for determining the downhole equivalent impact torque of the drill collar joint as described in any one of claims 1-2.

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