Judgment method and system suitable for rheological mode of polar region drilling fluid, medium and equipment

Abstract

The invention relates to the field of oil field drilling, and discloses a method, a system, a medium and equipment suitable for judging a rheological mode of drilling fluid in a polar region, and the method comprises the following steps: drawing a shearing stress-shearing rate rheological curve of the drilling fluid under various temperature conditions according to rheological property experimental measurement data; calculating the plastic viscosity, the dynamic shear force, the flow index and the consistency coefficient of the drilling fluid; fitting the rheological curve of the drilling fluid under each temperature measurement condition based on the plastic viscosity, the dynamic shear force, the flow index, the consistency coefficient and the constitutive equation of the four rheological modes; wherein the four rheological modes comprise a Bingham mode, a power law mode, a Casson mode and a Heschel-Balcoril mode; drawing a fitting curve according to a fitting result, and solving mean square errors and judgment coefficients of the four rheological modes under each temperature condition; and judging the applicability of the four rheological modes to the polar drilling fluid measured under different temperature conditions through the judgment coefficients so as to determine the rheological mode with the best applicability.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield drilling, and in particular to a method, system, medium and equipment for determining a rheological pattern of polar drilling fluid. Background Art

[0002] According to statistics, the proven conventional oil and gas reserves in the Arctic region currently exceed 400×10 8 m 3 (240 billion barrels), mainly distributed in the Beaufort Sea of ​​Alaska and northwestern Canada. In the Barents Sea, Sakhalin Island and Greenland, more than half of the oil and gas resources are located in waters less than 100 meters deep. However, due to the harsh natural environment, complex geological conditions and harsh environmental protection in polar regions, conventional land and offshore processes are poorly applicable in polar regions. The average thickness of the permafrost layer in the Arctic region is 400~900 meters, and the deepest thickness is 1400 meters. The ambient temperature is -50℃~-4℃. During the drilling process in the polar cold sea, the temperature difference above the mud line is large, and the temperature and pressure distribution in the wellbore is quite different from that of the conventional wellbore. It is necessary to improve the existing drilling parameter optimization design method. As the well depth increases, the formation temperature gradually increases, and the wellbore fluid continues to exchange heat with the formation and the pipe string, which causes the wellbore fluid temperature in the upper wellbore to continue to rise, causing the pore fluid in the upper formation to melt, changing its rock and soil, and rock mechanical properties, and it is very easy to cause wellbore instability. At the same time, it will also cause the fluid in the space between the pipe string and the formation, and between the pipe string and the pipe string annulus to expand due to heat, resulting in annular space pressure and causing the pipe string to fail.

[0003] Different rheological modes are applicable to different temperature, pressure and shear rate ranges. In practical applications, they need to be optimized according to the characteristics of the drilling fluid and the environmental conditions of use. At present, there are still deficiencies in the research on the optimal application range of each model. With the increase in the depth of polar drilling, the drilling fluid system used in the large temperature difference and alternating environmental changes is more complex, and the rheological mode of the existing fixed drilling fluid has a large error. In order to ensure the drilling safety of the polar drilling process, it is necessary to understand the rheology of the drilling fluid downhole to ensure the safety of the drilling process.

[0004] Therefore, how to effectively predict the different manifolds of drilling fluid under different drilling depth conditions to improve the drilling efficiency of the drilling fluid injection area in the oil field is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a method, system, medium and equipment for determining the rheological pattern of polar drilling fluid, which can effectively predict the different flow shapes of drilling fluid under different drilling depth conditions and improve the drilling efficiency of the drilling fluid injection area in the oil field.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for determining the rheological mode of polar drilling fluid, comprising: drawing the shear stress-shear rate rheological curve of drilling fluid under various temperature conditions according to the rheological experimental measurement data, and calculating the plastic viscosity, dynamic shear force, fluidity index and consistency coefficient of the drilling fluid; fitting the rheological curve of the drilling fluid under various temperature measurement conditions based on the plastic viscosity, dynamic shear force, fluidity index and consistency coefficient, and the constitutive equations of the four rheological modes; wherein the four rheological modes include Bingham mode, power law mode, Casson mode and Herschel-Balkoli mode; drawing the fitting curve according to the fitting result, and obtaining the mean square error and determination coefficient of the four rheological modes under various temperature conditions; judging the applicability of the four rheological modes to the polar drilling fluid measured under different temperature conditions by the determination coefficient, so as to determine the rheological mode with the best applicability.

[0007] Furthermore, the shear stress of the Bingham mode is:

[0008] In the formula, is the shear stress, is the dynamic shear force, is the Bingham plastic viscosity, is the shear rate.

[0009] Furthermore, the shear stress of the power-law mode is:

[0010] In the formula, is the shear stress, is the consistency coefficient, is the shear rate, Is the fluidity index.

[0011] Furthermore, the shear stress of the Casson mode is:

[0012] In the formula, is the shear stress, is the Casson yield stress, is the Casson plastic viscosity, is the shear rate.

[0013] Furthermore, the shear stress of the Herschel-Balkoli model is:

[0014] In the formula, is the shear stress, is the dynamic shear force, is the consistency coefficient, is the shear rate.

[0015] Furthermore, the coefficient of determination is:

[0016] In the formula, is the determination coefficient, is the ith experimental data, is the total number of experimental data sets, is the mean shear velocity, is the mean shear stress.

[0017] Furthermore, the applicability of the four rheological modes for the polar drilling fluids measured under different temperature conditions is judged by the determination coefficient to determine the rheological mode with the best applicability, including: the closer the determination coefficient is to 1, the better the applicability of the rheological mode.

[0018] A rheological mode judgment system suitable for polar drilling fluid comprises: a first processing module, which draws the shear stress-shear rate rheological curve of drilling fluid under various temperature conditions according to rheological experimental measurement data, and calculates the plastic viscosity, dynamic shear force, fluidity index and consistency coefficient of the drilling fluid; a second processing module, which fits the rheological curve of the drilling fluid under various temperature measurement conditions based on the plastic viscosity, dynamic shear force, fluidity index and consistency coefficient, and the constitutive equations of four rheological modes; wherein the four rheological modes include Bingham mode, power law mode, Casson mode and Herschel-Balkoli mode; a third processing module, which draws the fitting curve according to the fitting result, and obtains the mean square error and determination coefficient of the four rheological modes under various temperature conditions; and a determination module, which judges the applicability of the four rheological modes to the polar drilling fluid measured under different temperature conditions through the determination coefficient, so as to determine the rheological mode with the best applicability.

[0019] A computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform any of the above methods.

[0020] A computing device comprises: one or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing any of the above methods.

[0021] The present invention adopts the above technical solution, which has the following advantages: The present invention judges the applicability of four rheological modes for polar drilling fluids measured under different temperature conditions through determination coefficients. The closer the determination coefficient is to 1, the better the applicability of the rheological mode is. The rheological mode with the best applicability is determined, and the rheological mode judgment of drilling fluids in different environments during polar drilling is realized, thereby improving the drilling efficiency of the oilfield drilling fluid injection area and reducing the drilling cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a flow chart of a method for determining a rheological mode applicable to polar drilling fluids in an embodiment of the present invention; Figure 2 It is a comparison curve of the drilling fluid and the rheological mode in the embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to understand the rheological properties of drilling fluids underground and ensure the drilling safety during polar drilling, the present invention provides a method, system, medium and equipment for determining the rheological mode of polar drilling fluids, which includes S1, drawing the shear stress-shear rate rheological curves of drilling fluids under various temperature conditions based on rheological experimental measurement data (including drilling fluid density, drilling fluid viscosity, fluidity index, drilling fluid thermal conductivity, and drilling fluid specific heat capacity), and calculating the plastic viscosity and dynamic shear force of the drilling fluid. , fluidity index n, and consistency coefficient K. S2. Use the constitutive equations of the four rheological modes to fit the rheological curves of the drilling fluid under various temperature measurement conditions. S3. Draw the fitting curve based on the fitting results to obtain the mean square error and determination coefficient R of the four rheological modes under various temperature conditions. 2 , R 2 It is calculated by linear fitting of actual drilling fluid shear stress-shear rate, which indicates the fitting effect of actual data. Shear stress is obtained by measuring after setting the shear rate in the rheological instrument. S4. Determination coefficient R 2 To determine the applicability of the four rheological modes for the polar drilling fluids tested under different temperature conditions, R 2 The closer to 1, the better the applicability of the rheological mode. The present invention can realize the rheological mode judgment of drilling fluid in different environments during polar drilling, so as to control the rheological properties of polar drilling fluid, realize the hydraulic parameter control of drilling fluid, improve the rock breaking ability and rock carrying efficiency of drilling, increase the drilling speed, give full play to the maximum hydraulic performance of drilling fluid, and reduce drilling costs.

[0024] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0026] In one embodiment of the present invention, a method for determining the rheological pattern of polar drilling fluid is provided. Figure 1 As shown, the method comprises the following steps: 1) Based on the rheological test measurement data, draw the shear stress-shear rate rheological curve of drilling fluid under various temperature conditions, and calculate the plastic viscosity and dynamic shear force of drilling fluid , fluidity index n and consistency coefficient K; 2) Based on plastic viscosity, dynamic shear force, flow index and consistency coefficient, as well as the constitutive equations of four rheological modes, the rheological curves of the drilling fluid under various temperature measurement conditions are fitted; the four rheological modes include Bingham mode, power law mode, Casson mode and Herschel-Balkoli mode; 3) Draw a fitting curve based on the fitting results, and obtain the mean square error and determination coefficient of the four rheological modes under each temperature condition; 4) The applicability of the four rheological modes for the polar drilling fluids measured under different temperature conditions is determined by the determination coefficient to determine the rheological mode with the best applicability.

[0027] In the above step 2), the shear stress of the Bingham mode is:

[0028] In the formula, is the shear stress of the Bingham mode, is the dynamic shear force (i.e. dynamic shear stress), is the Bingham plastic viscosity, is the shear rate.

[0029] The shear stress of the power-law mode is:

[0030] In the formula, is the shear stress in the power-law mode, is the consistency coefficient, is the shear rate, Is the fluidity index.

[0031] The shear stress of the Casson mode is:

[0032] In the formula, is the shear stress of the Casson mode, is the Casson yield stress, is the Casson plastic viscosity, is the shear rate.

[0033] The shear stress of the Herschel-Balkoli model is:

[0034] In the formula, is the shear stress of the Herschel–Balkoli model, is the dynamic shear force, is the consistency coefficient, is the shear rate.

[0035] In the above step 3), a fitting curve is drawn based on the fitting results to obtain the mean square error and determination coefficient R of the four rheological modes under each temperature condition. 2 , specifically: Calculation of shear stress from Bingham model linear regression :

[0036] is the dynamic shear force; is the Bingham plastic viscosity; is the shear rate; Power law model linear regression shear stress :

[0037] is the shear rate; is the consistency coefficient; , , , .

[0038] Calculation of shear stress using linear regression of power law model :

[0039] in, , , , .

[0040] Calculation of the Herschel-Balkoli model linear regression shear stress :

[0041] in, , , , is the Heba yield value.

[0042] In step 3) above, the coefficient of determination is:

[0043] In the formula, is the determination coefficient, is the ith experimental data, is the total number of experimental data sets, is the mean shear velocity, is the mean shear stress.

[0044] In the above step 4), the applicability of the four rheological modes for the polar drilling fluids measured under different temperature conditions is determined by the determination coefficient to determine the rheological mode with the best applicability, including: the closer the determination coefficient is to 1, the better the applicability of the rheological mode, such as Figure 2 shown.

[0045] Specifically, through the determination coefficient R 2 Determine the applicability of the four rheological modes for the polar drilling fluids tested under different temperature conditions. The closer it is to 0, the smaller the correlation between x and y, and the worse the linear regression effect; conversely, The closer it is to 1, the closer the correlation between x and y is, and the better the regression effect is. Measures the degree of linear correlation, where some experimental data are recorded as , , ˙˙˙ , variables and The linear correlation parameter Therefore, the correlation coefficient Determine which rheological model best fits the experimental data.

[0046] Fourteen drilling fluids (A1~A14) were selected and the deviation values ​​were calculated respectively. The results are shown in Table 1. The errors all meet the use requirements and are within the specified range, which can be applied to the determination method of the rheological mode of polar drilling fluids.

[0047] Table 1 Evaluation results of various rheological modes of different drilling fluids in each measuring point data

[0048] In one embodiment of the present invention, a system for determining the rheological mode of polar drilling fluid is provided, which comprises: The first processing module, based on the rheological test measurement data, draws the shear stress-shear rate rheological curve of the drilling fluid under various temperature conditions, and calculates the plastic viscosity and dynamic shear force of the drilling fluid. , fluidity index n and consistency coefficient K; The second processing module is based on plastic viscosity and dynamic shear force. , fluidity index n and consistency coefficient K, as well as the constitutive equations of four rheological modes, are used to fit the rheological curves of the drilling fluid under various temperature measurement conditions; the four rheological modes include Bingham mode, power law mode, Casson mode and Herschel-Balkoli mode; The third processing module draws a fitting curve based on the fitting results to obtain the mean square error and determination coefficient of the four rheological modes under each temperature condition; The determination module determines the applicability of the four rheological modes for the polar drilling fluids measured under different temperature conditions through the determination coefficient, so as to determine the rheological mode with the best applicability.

[0049] In the above embodiment, the shear stress of the Bingham mode is:

[0050] In the formula, is the shear stress, is the dynamic shear force, is the Bingham plastic viscosity, is the shear rate.

[0051] The shear stress of the power-law mode is:

[0052] In the formula, is the shear stress, is the consistency coefficient, is the shear rate, is the consistency coefficient.

[0053] The shear stress of the Casson mode is:

[0054] In the formula, is the shear stress, is the Casson yield stress, is the Casson plastic viscosity, is the shear rate.

[0055] The shear stress of the Herschel-Balkoli model is:

[0056] In the formula, is the shear stress, is the dynamic shear force, is the consistency coefficient, is the shear rate.

[0057] In the above embodiment, the determination coefficient is:

[0058] In the formula, is the determination coefficient, is the ith experimental data, is the total number of experimental data sets, is the mean shear velocity, is the mean shear stress.

[0059] In the above embodiment, the applicability of the four rheological modes for the polar drilling fluids measured under different temperature conditions is judged by the determination coefficient to determine the rheological mode with the best applicability, including: the closer the determination coefficient is to 1, the better the applicability of the rheological mode.

[0060] The system provided in this embodiment is used to execute the above-mentioned method embodiments. Please refer to the above-mentioned embodiments for specific processes and detailed contents, which will not be repeated here.

[0061] In one embodiment of the present invention, a computing device is provided, which may be a terminal, and may include: a processor, a communication interface, a memory, a display screen, and an input device. Among them, the processor, the communication interface, and the memory communicate with each other through a communication bus. The processor is used to provide computing and control capabilities. The memory includes a non-volatile storage medium and an internal memory, and the non-volatile storage medium stores an operating system and a computer program. When the computer program is executed by the processor, the method in each of the above embodiments is implemented; the internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a management network, NFC (near field communication) or other technologies. The display screen may be a liquid crystal display screen or an electronic ink display screen, and the input device may be a touch layer covered on the display screen, or a key, trackball or touchpad provided on the housing of the computing device, or an external keyboard, touchpad or mouse, etc. The processor may call the logic instructions in the memory.

[0062] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0063] In one embodiment of the present invention, a computer program product is provided, wherein the computer program product includes a computer program stored on a non-transitory computer-readable storage medium, wherein the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the methods provided by the above-mentioned method embodiments.

[0064] In one embodiment of the present invention, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium stores server instructions, and the computer instructions enable a computer to execute the methods provided in the above embodiments.

[0065] The above embodiment provides a computer-readable storage medium, whose implementation principle and technical effect are similar to those of the above method embodiment, and will not be repeated here.

[0066] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0067] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0068] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the rheological pattern of polar drilling fluids, characterized in that: include: Based on the rheological test measurement data, the shear stress-shear rate rheological curve of drilling fluid under various temperature conditions is drawn, and the plastic viscosity, dynamic shear force, fluidity index and consistency coefficient of the drilling fluid are calculated; Based on plastic viscosity, dynamic shear force, flow index and consistency coefficient, as well as the constitutive equations of four rheological modes, the rheological curves of drilling fluid under various temperature measurement conditions are fitted; the four rheological modes include Bingham mode, power law mode, Casson mode and Herschel-Balkoli mode; The fitting curve was drawn according to the fitting results, and the mean square error and determination coefficient of the four rheological modes under different temperature conditions were obtained; The applicability of the four rheological modes for the polar drilling fluids tested under different temperature conditions was determined by the determination coefficient to determine the rheological mode with the best applicability.

2. The method for determining the rheological mode of polar drilling fluid according to claim 1, characterized in that: The shear stress of the Bingham mode is: In the formula, is the shear stress, is the dynamic shear force, is the Bingham plastic viscosity, is the shear rate.

3. The method for determining the rheological mode of polar drilling fluid according to claim 1, characterized in that: The shear stress of the power-law mode is: In the formula, is the shear stress, is the consistency coefficient, is the shear rate, Is the fluidity index.

4. The method for determining the rheological mode of polar drilling fluid according to claim 1, characterized in that: The shear stress of the Casson mode is: In the formula, is the shear stress, is the Casson yield stress, is the Casson plastic viscosity, is the shear rate.

5. The method for determining the rheological mode of polar drilling fluid according to claim 1, characterized in that: The shear stress of the Herschel-Balkoli model is: In the formula, is the shear stress, is the dynamic shear force, is the consistency coefficient, is the shear rate.

6. The method for determining the rheological mode of polar drilling fluid according to claim 1, characterized in that: The coefficient of determination is: In the formula, is the coefficient of determination, is the ith experimental data, is the total number of experimental data sets, is the mean shear velocity, is the mean shear stress.

7. The method for determining the rheological mode of polar drilling fluid according to claim 1, characterized in that: The applicability of the four rheological modes for the polar drilling fluids measured under different temperature conditions is judged by the determination coefficient to determine the rheological mode with the best applicability, including: the closer the determination coefficient is to 1, the better the applicability of the rheological mode.

8. A system for determining the rheological pattern of polar drilling fluids, characterized in that: include: The first processing module, based on the rheological test measurement data, draws the shear stress-shear rate rheological curve of the drilling fluid under various temperature conditions, and calculates the plastic viscosity, dynamic shear force, fluidity index and consistency coefficient of the drilling fluid; The second processing module fits the rheological curve of the drilling fluid under various temperature measurement conditions based on plastic viscosity, dynamic shear force, flow index and consistency coefficient, as well as the constitutive equations of four rheological modes; the four rheological modes include Bingham mode, power law mode, Casson mode and Herschel-Balkoli mode; The third processing module draws a fitting curve based on the fitting results to obtain the mean square error and determination coefficient of the four rheological modes under each temperature condition; The determination module determines the applicability of the four rheological modes to the polar drilling fluids measured under different temperature conditions through the determination coefficient, so as to determine the rheological mode with the best applicability.

9. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform any one of the methods of claims 1 to 7.

10. A computing device, characterized in that: include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing any one of the methods described in claims 1 to 7.

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