Ground stress determining method combining drilling parameters and logging information
Through the combined drilling parameters and logging data, combined with digital drilling technology and rock physics experiments, a calculation model of rock strength under stress-free state was established, which solved the problem of determining the ground stress magnitude of the oil and gas reservoirs, and achieved continuous acquisition of the ground stress magnitude along the well depth, reducing costs and improving accuracy.
Patent Information
- Application Number
- CN202311873494.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-30
- Publication Date
- 2025-07-01
AI Technical Summary
In the prior art, there are difficulties in determining the ground stress magnitude of oil and gas reservoirs. In the existing methods, in situ measurement is difficult and costly, and indirect analysis has many influencing factors and poor accuracy.
The method of determining the ground stress magnitude of the combined drilling parameters and logging data is adopted. By collecting drilling data and using digital drilling technology in the laboratory after core extraction, combined with rock physics experiments, a calculation model of rock strength under stressless state is established to calculate the ground stress intensity along the well depth.
It realizes continuous acquisition of ground stress magnitude along the well depth, reduces costs, improves accuracy and reliability, and can analyze the entire well section, solving the problem of ground stress analysis of oil and gas reservoirs.
Smart Images
Figure CN120231584A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of oil and gas development, and in particular, to a method for determining the magnitude of in-situ stress by combining drilling parameters and logging data. Background Art
[0002] In-situ stress is one of the key parameters in oil and gas exploration and development, and is of great significance to engineering problems such as formation drillability, wellbore stability, and reservoir compressibility. At present, the main in-situ stress analysis methods used in oil and gas exploration and logging engineering are hydraulic fracturing (microseismic monitoring) method, borehole wall collapse method, core stress relief method, induced fracture method, and wave velocity anisotropy method, etc. However, the in-situ measurement methods among these methods are difficult to implement and costly; the indirect analysis methods have many influencing factors and poor accuracy. The main indoor experimental analysis methods include radial acoustic anisotropy method, triaxial acoustic emission method, differential strain method, stress (strain) recovery method, etc. In these indoor experimental analysis methods, the rock is separated from the in-situ storage environment of the formation stress, and it is difficult to simulate the real complex stress environment indoors, so the analysis error is relatively large.
[0003] Digital drilling technology is a new type of rock mechanics parameter measurement method developed in recent years. By collecting the forces on the drill bit and drilling parameters during the process of the drill bit rotating and drilling into the rock, the rock strength, elastic modulus, cohesion, and internal friction angle are analyzed. This technology has been applied to predicting rock bursts, analyzing the stability of tunnel surrounding rocks, and evaluating slope safety in tunnel excavation. This technology has also been used to evaluate the drillability of formations in drilling. Logging technology can preferably obtain the direction of in-situ stress. By using the Poisson's ratio and Young's modulus calculated by acoustic waves and analyzing the magnitude of in-situ stress through a theoretical model, however, the dynamic elastic constants of the rock obtained by acoustic waves are not consistent with the static elastic constants that actually characterize the mechanical properties of the rock, and there are some assumptions in the theoretical model that do not conform to the actual situation. Therefore, there is a great uncertainty in evaluating in-situ stress by logging technology.
[0004] Therefore, in the prior art, determining the magnitude of in-situ stress in oil and gas reservoirs is an urgent but unsolved problem. Summary of the Invention
[0005] The main purpose of the present invention is to provide a method for determining the magnitude of in-situ stress by combining drilling parameters and logging data, so as to solve the problem of difficult determination of the magnitude of in-situ stress in oil and gas reservoirs in the prior art.
[0006] To achieve the above object, according to one aspect of the present invention, a method for determining the magnitude of in-situ stress by combining drilling parameters and logging data is provided, including: collecting drilling data of a target well, and calculating the drilling strength σ of formation rock under in-situ stress conditions with drilling parameters along the well depth D; Core samples are taken from the target well. In the laboratory, plug cores are drilled from the obtained core samples using digital drilling technology, and drilling parameters are collected to calculate the rock strength σ under the stress-free state. R1 ; Rock physics experiments corresponding to logging parameters are carried out on the drilled core samples to obtain the corresponding logging parameters, and a model for calculating the rock strength σ under the stress-free state from the logging parameters is established. R ; According to this model, the strength σ of the formation rock under the stress-free condition along the well depth is calculated using the logging parameters. R2 ; According to the drilling strength σ D and the formation rock strength σ R2 the in-situ stress strength σ along the well depth is calculated S and the in-situ stress magnitude is obtained based on the in-situ stress strength σ S where σ S = σ D - σ R2 .
[0007] Further, during the process of taking core samples from the target well for drilling, at least ten core samples are taken from the full-diameter drilling of the target well.
[0008] Further, during the process of drilling plug cores from the obtained core samples, at least three plug cores are drilled, and the size specifications of each plug core meet the requirements of the rock triaxial compression experiment.
[0009] Further, the rock physics experiments include at least one of formation elements and whole-rock minerals, and optionally density and natural gamma ray spectroscopy.
[0010] Further, the rock physics experiments include at least one of formation elements and whole-rock minerals, and optionally density and natural gamma ray spectroscopy. The correlation between each experimental parameter and the rock strength σ under the stress-free state is analyzed, and sensitive parameters are screened. Based on the sensitive parameters, a calculation model for the rock strength σ under the stress-free state is established. R1 R1
[0011] Further, the data model includes a multiple regression model or a neural network model.
[0012] Further, all the logging data at the burial depths of the core samples are extracted, and the logging data are standardized using the experimental parameters in the rock physics experiments.
[0013] Further, the standardized logging data are passed through the calculation model of the rock strength σ under the stress-free state, and the formation rock strength σ along the well depth of the target well is calculated. R1 R2 .
[0014] Further, based on the drilling strength σ D and the formation rock strength σ R2Calculate the in-situ stress intensity σ along the well depth S and calculate the in-situ stress intensity σ for the entire well section of the target well S .
[0015] Furthermore, obtain the in-situ stress intensity σ at different depths of the target well S and establish a model for calculating the actual in-situ stress magnitude from the in-situ stress obtained by in-situ stress testing and the in-situ stress intensity σ S .
[0016] Furthermore, process the in-situ stress intensity σ of the entire well section of the target well according to the model for calculating the actual in-situ stress magnitude from the in-situ stress intensity σ S to obtain the in-situ stress magnitude of the entire well section of the target well S .
[0017] Applying the technical solution of the present invention, the method for determining the in-situ stress magnitude by combining drilling parameters and well logging data in this application includes: collecting the drilling data of the target well and calculating the drilling strength σ of the formation rock under in-situ stress conditions with the drilling parameters along the well depth D ; taking cores from the target well for drilling, using digital drilling technology in the laboratory to drill plug cores from the obtained cores, and collecting the drilling parameters to calculate the rock strength σ in the stress-free state R1 ; conducting rock physics experiments corresponding to the well logging parameters on the drilled cores and obtaining the corresponding well logging parameters, and establishing a model for calculating the rock strength σ in the stress-free state from the well logging parameters R ; calculating the strength σ of the formation rock under stress-free conditions along the well depth according to this model using the well logging parameters R2 ; calculating the in-situ stress intensity σ along the well depth according to the drilling strength σ D and the formation rock strength σ R2 and obtaining the in-situ stress magnitude according to the in-situ stress intensity σ S wherein σ S =σ S -σ D -σ R2 .
[0018] By using the method for determining the in-situ stress magnitude by combining drilling parameters and well logging data in this application, it is possible to address the problem of difficult determination of the in-situ stress magnitude in oil and gas reservoirs. Combining the advantages of directly analyzing the formation mechanical strength with drilling data and analyzing the formation rock properties with well logging data, continuously obtain the in-situ stress magnitude along the well depth. Making full use of the originally idle drilling parameters, it has the advantages of lower cost than on-site experiments and can be analyzed for the entire well section, and has a higher reliability compared with well logging interpretation of the in-situ stress magnitude. Combining with the mature well logging in-situ stress direction interpretation technology, it can better solve the problem of in-situ stress analysis in oil and gas reservoirs, which is of great significance for oil and gas exploration and development BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:
[0020] Figure 1 It shows a schematic flow chart of a method for determining the in-situ stress magnitude by combining drilling parameters and logging data according to a specific embodiment of the present invention. Detailed implementation manners
[0021] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.
[0022] It should be pointed out that unless otherwise specified, all technical and scientific terms used in this application have the same meanings as those commonly understood by those of ordinary skill in the technical field to which this application belongs.
[0023] In the present invention, unless otherwise stated, the orientation words such as "upper, lower, top, bottom" are usually in the directions shown in the accompanying drawings, or in the vertical, perpendicular or gravitational directions of the components themselves; similarly, for the convenience of understanding and description, "inner, outer" refer to the inner and outer of the contours of the components themselves, but the above orientation words are not used to limit the present invention.
[0024] In order to solve the problem of difficult determination of in-situ stress in oil and gas reservoirs in the prior art, this application provides a method for determining the in-situ stress magnitude by combining drilling parameters and logging data.
[0025] The method for determining the in-situ stress magnitude by combining drilling parameters and logging data in this application includes: collecting the drilling data of the target well, and calculating the drilling strength σ of the formation rock under in-situ stress conditions with the drilling parameters along the well depth D ; taking cores from the target well drilling, using digital drilling technology in the laboratory to drill plug cores from the obtained cores, and collecting drilling parameters to calculate the rock strength σ in the stress-free state R1 ; conducting rock physics experiments corresponding to logging parameters on the drilled cores and obtaining the corresponding logging parameters, and establishing a model for calculating the rock strength σ in the stress-free state from the logging parameters R ; calculating the strength σ of the formation rock under stress-free conditions along the well depth according to the logging parameters using this model R2 ; calculating the in-situ stress strength σ along the well depth according to the drilling strength σ D and the formation rock strength σ R2 and obtaining the in-situ stress magnitude according to the in-situ stress strength σ S and where σ S = σ S = σ D - σR2 .
[0026] By using the method for determining the in-situ stress magnitude from the combined drilling parameters and logging data in this application, it is possible to address the problem of difficult determination of in-situ stress in oil and gas reservoirs. Combining the advantages that drilling data can directly analyze the formation mechanical strength and logging data can analyze the formation rock properties, the in-situ stress magnitude can be continuously obtained along the well depth. Making full use of the originally idle drilling parameters, it has the advantages of lower cost than on-site experiments and can be analyzed for the entire well section. Compared with logging interpretation of in-situ stress magnitude, it has the advantage of high reliability. Combining with the mature logging in-situ stress direction interpretation technology, it can better solve the problem of in-situ stress analysis in oil and gas reservoirs, which is of great significance for oil and gas exploration and development.
[0027] Specifically, collect the drilling data of the target well, and use the drilling parameters to calculate the drilling strength σ of the formation rock under the condition of in-situ stress along the well depth D .
[0028] Specifically, during the process of drilling and coring the target well, take at least ten cores with the full diameter of the target well.
[0029] Specifically, during the process of drilling plug cores from the obtained cores, drill at least three plug cores, and the size specifications of each plug core meet the requirements of rock triaxial compressive experiments.
[0030] Specifically, the rock physical experiments include at least one of formation elements and whole-rock minerals, and optionally density and natural gamma ray spectrometry.
[0031] Specifically, the rock physical experiments include at least one of formation elements and whole-rock minerals, and optionally density and natural gamma ray spectrometry. Analyze the correlation between each experimental parameter and the rock strength σ in the stress-free state and screen sensitive parameters, and establish a calculation model for the rock strength σ in the stress-free state according to the sensitive parameters R1 R1 of.
[0032] Specifically, the data model includes a multiple regression model or a neural network model.
[0033] Specifically, extract all the logging data at the depths where the cores are buried, and standardize the logging data using the experimental parameters in the rock physical experiments.
[0034] Specifically, pass the standardized logging data through the calculation model of the rock strength σ in the stress-free state, and calculate the formation rock strength σ along the well depth of the target well R1 R2 .
[0035] Specifically, then calculate the in-situ stress strength σ along the well depth according to the drilling strength σ D and the formation rock strength σ R2 S , calculate the in-situ stress intensity σ of the entire well section of the target well S .
[0036] Specifically, obtain the in-situ stress intensity σ at different depths of the target well S and establish a model for calculating the actual in-situ stress magnitude from the in-situ stress obtained by in-situ stress testing with the in-situ stress intensity σ S .
[0037] Specifically, according to the model for calculating the actual in-situ stress magnitude from the in-situ stress intensity σ S , process the in-situ stress intensity σ of the entire well section of the target well S to obtain the in-situ stress magnitude of the entire well section of the target well.
[0038] In this application, drilling is a mechanical behavior that continuously fractures formation rocks along the well depth. The strength of formation rocks can be analyzed through drilling parameters and response parameters. This strength is a comprehensive reflection of two types of strengths, which is referred to as drilling strength in this method. The first is the inherent strength of formation rocks (hereinafter referred to as rock strength), which is jointly determined by the strength of diagenetic minerals and cements. The second is under formation conditions (determined by the external environment at the depth of oil and gas reservoirs, the influence of temperature on rock strength can be ignored, mainly the influence of in-situ stress), as the effective stress increases, the rock strength increases non-linearly. This part of the strength can be called in-situ stress intensity. That is: σ D =σ R +σ S , where σ D is the drilling strength, σ R is the rock strength, and σ S is the in-situ stress intensity. The drilling strength σ is calculated from drilling parameters D , establish the relationship between rock strength and logging parameters, and calculate the rock strength σ from logging data R , σ D minus σ R to obtain the in-situ stress intensity σ S , and after calibration, σ S can represent the in-situ stress magnitude. As Figure 1 shown, it is the technical flow chart for obtaining the in-situ stress magnitude in this application. In a specific embodiment of this application, the number of cores obtained is at least ten, and three plug cores are taken from each core. The specific method is:
[0039] S1, collect the drilling data of the target well, and calculate the drilling strength σ of the formation rocks under in-situ stress conditions along the well depth using drilling parameters D .
[0040] S2, during the process of taking cores from the target well during drilling, take at least ten cores with the full diameter of the target well.
[0041] S3. During the process of obtaining the cored plug cores, at least three plug cores are drilled, and the size specifications of each plug core meet the requirements of the rock triaxial compressive strength test.
[0042] S4. The rock physical experiments include at least one of formation elements and whole-rock minerals, and optionally density and natural gamma ray spectroscopy.
[0043] S5. The rock physical experiments include at least one of formation elements and whole-rock minerals, and optionally density and natural gamma ray spectroscopy. Analyze the correlation between each experimental parameter and the rock strength σ under the stress-free state and screen the sensitive parameters, and establish a calculation model of the rock strength σ under the stress-free state according to the sensitive parameters. R1 of R1
[0044] S6. The data model includes a multiple regression model or a neural network model.
[0045] S7. Extract all the logging data at the depths where the cores are buried, and standardize the logging data using the experimental parameters in the rock physical experiments.
[0046] S8. Pass the standardized logging data through the calculation model of the rock strength σ under the stress-free state, and calculate the formation rock strength σ along the well depth of the target well. R1 R2
[0047] S9. Then, calculate the in-situ stress strength σ along the well depth according to the drilling strength σ D and the formation rock strength σ R2 , and calculate the in-situ stress strength σ of the entire well section of the target well. S S
[0048] S10. Obtain the in-situ stress strength σ at different depths of the target well S and establish a model for calculating the actual in-situ stress magnitude from the in-situ stress strength σ S obtained by the in-situ in-situ stress test.
[0049] S11. Process the in-situ stress strength σ of the entire well section of the target well according to the model for calculating the actual in-situ stress magnitude from the in-situ stress strength σ S to obtain the in-situ stress magnitude of the entire well section of the target well. S
[0050] From the above description, it can be seen that by using the method for determining the magnitude of in-situ stress with the combined drilling parameters and logging data in this application, it is possible to address the problem of difficult determination of in-situ stress in oil and gas reservoirs. By combining the advantages that the formation mechanical strength can be directly analyzed with drilling data and the formation rock properties can be analyzed with logging data, the magnitude of in-situ stress can be continuously obtained along the well depth. Making full use of the originally idle drilling parameters, it has the advantages of lower cost than on-site experiments and can be analyzed for the entire well section. Compared with logging interpretation of the magnitude of in-situ stress, it has the advantage of high reliability. Combining with the mature logging in-situ stress direction interpretation technology, it can better solve the problem of in-situ stress analysis in oil and gas reservoirs, which is of great significance for oil and gas exploration and development.
[0051] Obviously, the above-described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0052] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. 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, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0053] It should be noted that the terms "first", "second", etc. in the description, claims, and drawings of this application are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.
[0054] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A method for determining the magnitude of in-situ stress by combining drilling parameters and logging data, characterized in that Including: Collect the drilling data of the target well and calculate the drilling intensity σ along the well depth using the drilling parameters D ; Drill cores from the target well, and use digital drilling technology in the laboratory to drill plug cores from the obtained cores, and collect drilling parameters to calculate the rock strength σ under the stress-free state R1 ; Conducting rock physics experiments corresponding to logging parameters on the drilled core and obtaining corresponding logging parameters; According to the rock strength σ under the stress-free state R1 and well logging parameters, the formation rock strength σ R2 ; According to the drilling strength σ D and the formation rock strength σ R2 the in-situ stress strength σ along the well depth is calculated S and based on the in-situ stress strength σ S the in-situ stress magnitude is obtained, where σ S = σ D - σ R2 .
2. The method for determining the magnitude of in-situ stress by combining drilling parameters and logging data according to claim 1, wherein, During the process of drilling the core from the target well, taking at least ten cores by full-diameter drilling of the target well.
3. The method for determining the in-situ stress magnitude based on the combined drilling parameters and logging data according to claim 1, wherein, During the process of drilling the plug core from the obtained core, drilling at least three plug cores.
4. The method for determining the in-situ stress magnitude from the combined drilling parameters and logging data according to any one of claims 1 to 3, characterized in that, The rock physics experiment includes at least one of formation elements and whole-rock minerals.
5. The method for determining the magnitude of in-situ stress by combining drilling parameters and logging data according to claim 4, characterized in that, The rock physics experiments at least include: formation elements and whole rock minerals, analyze the correlation between each experimental parameter and the rock strength σ under the stress-free state R1 and screen sensitive parameters, and establish a calculation model of the rock strength σ under the stress-free state according to the sensitive parameters. R1 6. The method for determining the magnitude of in-situ stress by combining drilling parameters and logging data according to claim 5, characterized in that, The data model includes a multiple regression model or a neural network model.
7. The method for determining the magnitude of in-situ stress by combining drilling parameters and logging data according to claim 5, characterized in that, Extracting the logging data at the buried depths of all the cores and standardizing the logging data using the experimental parameters in the rock physics experiment.
8. The method for determining the magnitude of in-situ stress by combining drilling parameters and logging data according to claim 7, characterized in that, Pass the processed well logging data through the calculation model of the rock strength σ under the stress-free state R1 to calculate the formation rock strength σ along the well depth of the target well R2 .
9. The method for determining the in-situ stress magnitude by combining drilling parameters and logging data according to claim 8, characterized in that, In the process of calculating the in-situ stress intensity σ D along the well depth according to the drilling strength σ R2 and the formation rock strength σ S , calculate the in-situ stress intensity σ S of the entire well section of the target well.
10. The method for determining the magnitude of in-situ stress by combining drilling parameters and logging data according to claim 9, characterized in that, Obtain the in-situ stress intensity σ at different depths of the target well S And establish a model for calculating the actual in-situ stress magnitude by using the in-situ stress obtained from in-situ stress tests and the in-situ stress intensity σ S to calculate the actual in-situ stress magnitude.
11. The method for determining the magnitude of in-situ stress by combining drilling parameters and logging data according to claim 9, characterized in that, According to the model for calculating the actual in-situ stress magnitude from the in-situ stress intensity σ S process the in-situ stress intensity σ S of the entire well section of the target well to obtain the in-situ stress magnitude of the entire well section of the target well.