Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
CNPC Engineering Technology R&D Company Limited
Study on Parameters Optimisation of Fracturing Stages & Perforation Clusters in Luzhou Deep Shale Gas Horizontal Wells Based on Integrated Drilling and Logging Data
Yuan, L. (CNPC Engineering Technology R&D Company Limited) | Hu, S. L. (CNPC Oilfield Service Company Limited) | Mu, L. Y. (CNPC Engineering Technology R&D Company Limited) | Wang, D. L. (CNPC Oilfield Service Company Limited) | Yang, X. T. (CNPC Engineering Technology R&D Company Limited) | Song, Y. (PetroChina Southwest Oil and Gas Field Branch) | Wang, J. C. (PetroChina Xinjiang Oilfield Branch)
Abstract Considering the high temperature environment and high operation cost, only a small number of deep shale gas horizontal wells in Luzhou would conduct logging in horizontal sections. If the neighboring wells were rather far away, it would be difficult to accurately obtain the reservoir heterogeneity along the lateral; therefore, most completions were designed geometrically, with little or no guidance for the location optimizations of fracturing intervals & perforation clusters. In such a case, it was most likely to occur a low opening rate of perforation clusters in the same stage, resulting in a poor stimulation effect. For the first time, this paper proposed a novel optimization method for the fracturing parameters of horizontal sections based on integrated drilling & logging data. Firstly, the available data type was evaluated. If the logging data was missing, geometrically designed stages and clusters would be relocated based on drilling data; otherwise, it could be easily accessible by logging data. Then, when relocating, the drilling data (torque, drilling pressure, mechanical drilling speed, etc.) were used to calculate the rock mechanical specific energy (RMSE) along the lateral. Next, the RMSE values were calibrated with the indoor rock mechanics experiments to establish a standard classification of Luzhou deep shale rock hardness. Finally, based on the principle of similar rock hardness, the perforation clusters in the same fracturing stage were re-positioned to ensure their locations at the same or adjacent rock hardness level. The above design method was applied and verified in Luzhou deep shale gas wells, the results demonstrated that, after the geometrically distributed segments & clusters were adjusted and relocated, their positions had a high matching rate of 85.47% with the optimized design of fracturing segments & perforation clusters using logging data. What's more, the VideoLog technology was utilized to observe the erosion of the perforation holes after fracturing, 9 out of 11 perforation clusters effectively opened, with an opening rate of up to 81.8%. Compared to the previous geometrically fracturing design with only 2 out of 10 perforation clusters effectively opened, it was a 124.7% improvement. In addition, the shape and size of the opening perforation holes were the same after erosion, which indicated that the hardness of the rock at the locations where the perforation holes were arranged was nearly the same, resulting in almost all clusters simultaneously opening & initiating. Therefore, this method can effectively compensate for the blindness of the segment & cluster parameters design caused by the lack of logging data, ensure the effective opening efficiency of perforation clusters in the same stage, and maximize the uniformity and effectiveness of reservoir stimulation.
- Asia (1.00)
- North America > United States > Texas (0.69)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- North America > United States > New Mexico > Permian Basin > Wolfcamp Formation (0.99)
- Asia > China > Sichuan > Sichuan Basin > Southwest Field > Longwangmiao Formation (0.99)
Experimental Study on Indoor Multi-Cluster Fracturing Based on Distributed Fibre-Optical Monitoring
Wang, Su (China University of Petroleum (Beijing)) | Chen, Mian (China University of Petroleum (Beijing)) | Chang, Zhi (CNPC Engineering Technology R&D Company Limited) | Zhang, Qixing (China University of Petroleum (Beijing)) | Lv, Jiaxin (China University of Petroleum (Beijing)) | Cui, Zhuang (China University of Petroleum (Beijing)) | Hou, Bing (China University of Petroleum (Beijing) at Karamay)
Abstract Hydraulic fracturing is an important stimulation technique for unconventional oil and gas fields, and real-time monitoring of fractures technology is crucial to evaluate the result of reservoir stimulation. This paper combines distributed sensing equipment based on OFDR with large-scale true triaxial fracturing physical simulation equipment. Then, the laboratory single-cluster and multiple-cluster hydraulic fracturing physical simulation experiments were carried out, while conducted real-time fracture monitoring using bare optical fibre. The experimental results indicate that the location and sequence of fractures initiation can be determined based on the strain evolution of the optical fibre. The general law of fracture propagation on fibre strain evolution can be obtained in single-cluster hydraulic fracturing experiments. In addition to determine the sequence and location of fractures initiation, multi-cluster experiments can also observe the mutual influence of different fractures, and the amount of liquid entering each fractures. These laboratory hydraulic fracturing experiments by distributed optical fibre sensing were conducted under true triaxial conditions, which can provide reference and guidance for on-site oilfield fracturing design.
- Asia > China (0.50)
- North America > United States > Texas (0.28)
- Asia > Middle East > Saudi Arabia (0.28)
- Research Report > New Finding (0.50)
- Research Report > Experimental Study (0.50)
- North America > United States > Texas > Permian Basin > Delaware Basin (0.99)
- North America > United States > New Mexico > Permian Basin > Delaware Basin (0.99)
- Well Completion > Hydraulic Fracturing (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Well Completion > Completion Monitoring Systems/Intelligent Wells > Downhole sensors & control equipment (0.69)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale gas (0.68)
Imaging Hydraulic Fractures in Laminated Shale Based on Quasi Tri-Axial Loading with In-Situ X-Ray CT Scan
Ren, Lejia (China University of Petroleum-Beijing) | Wang, Zhiwei (China University of Petroleum-Beijing) | Jiang, Fumin (China University of Petroleum-Beijing) | Sheng, Mao (China University of Petroleum-Beijing) | Tian, Shouceng (China University of Petroleum-Beijing) | Tan, Peng (CNPC Engineering Technology R&D Company Limited) | Chen, Zhaowei (CNPC Engineering Technology R&D Company Limited)
Abstract Shale is a rock with rich bedding structures that impact hydraulic fractures propagation with complex interactions. The X-ray CT scan is an effective approach to observe the interaction of hydraulic fractures with laminated bedding. However, the conventional experiments have been rarely observed the internal of the sample under in-situ conditions with fluid pumping and stress compression. This paper proposed an in-situ X-ray CT scan scheme and setup for hydraulic fracturing experiment with capacity of 2-inch rock cores. The typically continental shale oil rock was selected to be studied which is rich in bedding planes. The interaction phenomenon between bedding weak planes and hydraulic fractures were observed by the industrial CT machine with the resolution of 20 ฮผm length. The results show that the opening degree of bedding weak planes decreases under the in-situ stress with loading axial stress and confining stress. The bedding planes were activated to be opened while hydraulic fracturing pumping at certain conditions, which indicates that the propagation path of hydraulic fractures is simultaneously affected by the joint action of in-situ stress and bedding weak planes.
- Asia > China (0.98)
- Asia > Middle East > Saudi Arabia (0.28)
- Research Report > New Finding (0.67)
- Research Report > Experimental Study (0.48)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- North America > United States > South Dakota > Williston Basin > Bakken Shale Formation (0.99)
- North America > United States > North Dakota > Williston Basin > Bakken Shale Formation (0.99)
- North America > United States > Montana > Williston Basin > Bakken Shale Formation (0.99)
- Asia > China > Sichuan > Sichuan Basin (0.99)
High-Temperature-Resistant Thermal Shape Memory Polymers as Lost Circulation Materials for Fracture Formations
Zhao, Zhen (Research Institute of Petroleum Exploration & Development) | Sun, Jinsheng (CNPC Engineering Technology R&D Company Limited) | Liu, Fan (CNPC Engineering Technology R&D Company Limited) | Bai, Yingrui (China University of Petroleum (East China) (Corresponding author)) | Wang, Ren (CNPC Engineering Technology R&D Company Limited (Corresponding author)) | Geng, Yuan (China University of Petroleum (East China)) | Li, Yongjian (CNPC Engineering Technology R&D Company Limited) | Liu, Ce (CNPC Engineering Technology R&D Company Limited)
Summary Lost circulation during the drilling of fractured formations is one of the most challenging engineering problems. Shape memory polymers (SMPs) have been used as lost circulation materials, but most of them are not resistant to high temperatures. In this study, a high-temperature-resistant thermal shape memory epoxy resin (SME) was synthesized by conducting an orthogonal experiment using the glass transition temperature (Tg) as an index. The Tg of the SME synthesized by using the optimum formula was 124โ. This SME had good thermal stability, and its compression and tension stresses were 94.2 and 58.8 MPa, respectively. In addition, the thickness swelling ratio (Rrc) of the SME was optimized by performing another orthogonal experiment, and the Rrc of the SME prepared by using the optimized formulation (OSME) was 78.8%. The OSME did not swell at 25โ150โ in water, brine, or base fluid. The total size reduction percentage of the OSME was 1.7% after aging at 150โ, whereas that of a nutshell was 10.7%, indicating that OSME particles had better compression and temperature-resistance performance. The shape memory ratio (Rc) of the OSME was 6, 70, and 100% at 80, 120, and 125โ after being heated for 50 minutes, respectively, and it was fully activated in 5 minutes at 150โ. The breakthrough pressure of the plugging mud with or without the OSME was 15 MPa at 25, 80, 120, and 150โ when plugging the wedge fracture model with an inlet/outlet width of 3/1 mm. However, when plugging the wedge fracture model with an inlet/outlet width of 5/2 mm, the plugging slurry with the OSME could withstand a pressure of 3, 5, and 15 MPa at 80, 120, and 150โ, respectively, and the plugging mud with conventional lost circulation materials could bear a pressure of below 3 MPa at 80, 120, and 150โ. These results indicated that the OSME had good plugging and thermosensitive performance. OSME particles matched better with the fracture size, owing to their elastic and shape memory performance at above Tg. They migrated and bridged in fractures, aggregated and filled the pore space with other lost circulation materials, and formed a dense plugging layer at above Tg. Thus, the synthesized SME is a promising material for plugging high-temperature fracture formations while drilling.
- Asia > China (0.47)
- North America > United States > Texas (0.28)
- Europe > Norway > Norwegian Sea (0.24)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Study On Shear & Tensile Activation Of Hydraulic Fracturing In Natural Fractured Reservoirs
Zhang, Yang (China University of Petroleum, Beijing) | Qiao, Yan (CNPC Engineering Technology R&D Company Limited) | Zhou, Fujian (China University of Petroleum, Beijing) | Ren, Dengfeng (PetroChina Tarim Oilfield Company) | Liu, Yuzhang (China University of Petroleum, Beijing) | Bai, Jie (Research Institute of Petroleum Exploration & Development)
Abstract The most fundamental purpose of reservoir stimulation is to maximize stimulation volume. For reservoirs developed with natural fractures, the maximization of fracture activation (tensile & shear activation) area should be pursued. Many scholars have studied the mechanical conditions of natural fractures activation, and used stress shadow to optimize cluster spacing. However, there is a lack of in-depth research on fracture propagation law, relationship between fracture activation and stress shadow, and factors affecting natural fracture activation. In this paper, numerical simulation methods are used to establish a true three-dimensional hydraulic fracturing model for reservoirs with natural fractures, and the quantitative evaluation indicators of stress shadow area and activation degree of natural fractures are formed. By studying the effects of different natural fracture properties, mechanical and engineering parameters on fracture propagation, stress shadow and natural fracture activation, the main controlling factors affecting fracture propagation and turning, the relationship between fracture activation and stress shadow, and changing rules of fracture activation are clarified. Finally, the fracture turning and accuracy of model are verified by microseismic monitoring data. Studies have shown that large-scale, high-density natural fractures, high net pressure, low in-situ stress difference, and moderate stress-fracture angle (30ยฐ~60ยฐ) can easily divert the propagation of hydraulic fractures instead of expanding in the horizontal maximum principal stress (Shmax) direction. Fracture tensile activation has a strong positive correlation with stress shadow area, that is, tensile activation leads to the increase of stress shadow area, while fracture shear activation has almost no correlation. Fracture tensile & shear activation area is in a competitive relationship, and shear fractures are dominant when the stressfracture angle is 45-60ยฐ, the in-situ stress difference and pore pressure are high. The main controlling factors affecting activated fractures total area are geological factors and mechanical parameters, which are positively correlated with natural fracture density, dip angle, in-situ stress difference, pumping volume, pore pressure, negatively correlated with friction angle and cohesion, and have optimal values with fracture size (60m), stress-fracture angle (45ยฐ) and net pressure. Micro-seismic data show that when natural fractures density is high, the hydraulic fractures propagation direction deflects and doesn't expand in the horizontal maximum principal stress direction, which further verifies the accuracy of the method and conclusions. There is no obvious correlation between natural fracture activation area and stress shadow. It is not applicable to optimize cluster spacing of reservoirs with natural fractures only by stress shadow. The natural fracture activation area should be used as an indicator for measure optimization. In addition, this paper provides a reference for the selection of reservoir stimulation horizons, the formulation of working systems, and the realization of large hydraulic fracture diversion.
- Asia > China (0.69)
- North America > United States > Texas (0.28)
- North America > United States > Texas > Fort Worth Basin > Barnett Shale Formation (0.99)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tarim Basin (0.99)
Dynamic Response Mechanism and Prediction Model of Fractured Formation Loss
Gao, Reyu Y. (CNPC Engineering Technology R&D Company Limited) | Cui, Yi (CNPC Engineering Technology R&D Company Limited) | Liu, Yuhan H. (CNPC Engineering Technology R&D Company Limited) | Cui, Meng (CNPC Engineering Technology R&D Company Limited) | Zhao, Fei (CNPC Engineering Technology R&D Company Limited) | Ding, Yan (CNPC Engineering Technology R&D Company Limited)
ABSTRACT The deep fractured formation has the characteristics of complicated temperature and pressure environment and narrow safe density window, which makes it easy to lose during drilling. Most of the loss models established in the past only start from the perspective of mudflow and ignore the coupling between fluid and surrounding rock, which makes their application unsatisfactory. To better understand the dynamic response mechanism of fractured loss in the formation, and obtain the changes of fluid and formation in this process. A new model is developed to simulate the loss of drilling fluid, predict the total loss and the mud penetration distance, based on the stress-seepage coupling method of dual-porosity media and the non-Newtonian fluid seepage law. Using this model, the whole process of the loss is analyzed. It is found that the flow rate is rapid at first and then slow, and the total loss increases continuously. At the same time, the influence law of various parameters related to the formation and mud on the loss is studied. The results show that the bottom pressure, mud rheology, and initial width of fracture have significant effects on total loss. Among them, the total loss increases with the increase of bottom pressure and initial fracture width, and decreases with the increase of mud viscosity. The change of elastic modulus and Poisson's ratio has little effect on the total loss.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type (0.69)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management (1.00)
An Adaptative Well Trajectory Control Method for Drilling Automation
Junlong, Chen (CNPC Engineering Technology R&D Company Limited) | Xueping, Tang (CNPC Engineering Technology R&D Company Limited) | Xinmiao, Teng (CNPC Engineering Technology R&D Company Limited) | Wenkai, Gao (CNPC Engineering Technology R&D Company Limited)
ABSTRACT It is necessary to take some activities to correct the well-trajectory when it deviated from the designed well-path for the complex structural wells. In order to reduce the deviation from the planned well-path, we proposed a path following algorithm by backstepping method. The relative distance between the bit and planned well-path was calculated by the true vertical depth (TVD). The first and second order differential equations of the offset were established as the control function. Lyapunov function was constructed not only to verify the global consistent asymptotic stability of the system but also form a build-up rate control method. When the deviation between the real drilling trajectory and the planned well-path has exceeded the allowable threshold value, the algorithm automatically calculates the relative distance and angle, analyses and send the optimal strategy to the steering tools. The results show that the above algorithm can quickly track the designed well-path and ensure to avoiding oscillation. This method can be used in the future downhole closed-loop system. INTRODUCTION Downhole closed-loop steering drilling technology primarily employs automatic control systems to achieve dynamic adjustment of wellbore trajectory through real-time monitoring and analysis of borehole trajectory, and to ultimately achieve targeted drilling along the optimal borehole trajectory. After the downhole data is transmitted to the ground in real time, the ground system will dynamically analyse the downhole working conditions, send control instructions to the downhole executive mechanism, and form closed-loop control through two-way transmission of information in order to achieve real-time optimisation of drilling parameters and significantly increase drilling speed and reservoir drilling rate. The design of the downhole closed-loop control is predicated on the mechanical analysis and structure of the drilling instruments. The controller outputs the target curvature results by inputting the current position data (measured depth, inclination, and azimuth), the position and attitude of the target point, and the utmost dogleg that the drilling instrument is capable of achieving. The result of the controller is transmitted to the steering tools, and the interior structures of the bottom hole assembly (BHA) adapt to accommodate the new drilling trajectory.
- Asia > China (0.31)
- North America (0.29)
Fracture Geometries and Breakdown Pressures of Multi-Branch Radial Borehole Fracturing Influenced by Horizontal Stress Difference
Yong, Yuning (China University of Petroleum ) | Guo, Zhaoquan (CNPC Engineering Technology R&D Company Limited) | Tian, Shouceng (China University of Petroleum) | Wang, Tianyu (China University of Petroleum) | Sheng, Mao (China University of Petroleum) | Liao, Lulu (Sinopec Research Institute of Petroleum Engineering / China University of Petroleum)
ABSTRACT Multi-branch radial boreholes can be drilled and combined with hydraulic fracturing to efficiently stimulate tight gas reservoirs. This paper experimentally investigates how horizontal stress difference affects fracture geometry and breakdown pressure in multi-branch radial borehole fracturing by a true triaxial fracturing device. Six artificial rocks (395 mm ร 395 mm ร 395 mm) were cast for the experiments, which are divided into two groups by the azimuth of the radial borehole. The results show that fracture geometries are controlled by the rectification of a single radial borehole, the extrusion between the adjacent radial borehole row, and the deflection of the maximum horizontal stress. Fracture propagation is affected by the dynamic variation of the three effects. Decreasing the stress difference is favorable for fracture propagation along the radial borehole axis, while it lifts the breakdown pressure. Decreasing the azimuth lifts fracture extension distance parallel to the radial borehole axis and reduces the breakdown pressure. This research sheds light on the feasibility of radial borehole fracturing for reservoirs under various stress differences. INTRODUCTION Horizontal wells combining multi-stage hydraulic fracturing technology are commonly used to extract tight gas reservoirs. However, it still has the challenge that is the insufficient stimulation. Radial borehole fracturing is proposed recently, which combines the horizontal radial borehole with hydraulic fracturing (Huang et al., 2020a; Huang et al., 2020b; Kamel, 2016; Landers, 1998). This technology has the following procedure. Firstly, several radial boreholes, with diameters of no more than 50 mm, are drilled perpendicular to the axis of the vertical well. The fracturing fluid is then injected into the radial boreholes via the main well. After fracturing, the complex fracture network is generated in the reservoir finally. It has been applied in many fields with good effect (Bruni et al., 2007; Cinelli and Kamel, 2013; Cirigliano and Blacutt, 2007; Li et al., 2000; Maut et al., 2017; Ragab and Kamel, 2013). The multi-branch radial boreholes are favorable to communicating several sweet spots in the tight gas reservoir, which is also more economical than horizontal wells. So, radial borehole fracturing is anticipated to efficiently develop tight gas reservoirs or other unconventional reservoirs.
- Asia > India > Tripura > Assam-Arakan Basin (0.99)
- North America > United States > Louisiana > China Field (0.97)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
- (3 more...)
Development of a Wellbore Stability Prediction Model Using Multiple Regression with Missing Core Samples: A Case Study of the Shunbei Oil and Gas Field
Chang, Qifan (China University of Petroleum ) | Fu, Yun (China University of Petroleum ) | Zhou, Yitian (China University of Petroleum ) | Zheng, Lihui (China University of Petroleum ) | Li, Jie (China University of Petroleum ) | Jin, Yi (CNPC Engineering Technology R&D Company Limited)
ABSTRACT The Shunbei oil and gas field, characterized by its intricate deep fault-karst reservoirs and fractured carbonate lithology, presents formidable challenges to wellbore stability during drilling and completion phases, precipitating adverse events such as wellbore collapse and fluid loss. This study embarks on addressing the paucity of data integral for effective wellbore stability prediction in this region, employing a tripartite methodological approach: identification of pertinent data and influential factors, enhancement of multiple regression accuracy, and selection of controlling factors. The study revealed that the multiple linear regression model delivered the most precise predictions for both the leakage rate and well diameter expansion rate. Crucial factors such as geodetic coordinates, drilling pressure, and azimuth were identified as exerting substantial influence on wellbore stability. By scrutinizing primary controlling factors and underscoring the crucial role of drilling pressure and displacement in averting collapse and leakage, this study provides invaluable insights applicable to actual production settings. This study, while enhancing understanding of wellbore stability through analyzing key factors, does not delve into quantitative control strategies. Nevertheless, it provides a practical framework for better management of wellbore collapse and leakage in Shunbei oil and gas field. INTRODUCTION Meeting the global energy demands requires exploration and development of oil and gas fields (Cui et al., 2023). However, drilling and completion of deep fault-karst reservoirs such as the Shunbei field (Baozeng et al., 2020) present significant challenges due to wellbore instability issues. These issues include wellbore collapse, fluid loss, and other prevailing problems (Lixin, 2020), which can lead to extensive equipment damage, increased drilling and operational costs, and endanger the safety of personnel. The wellbore instability issues faced in the Shunbei field are primarily due to the fractured carbonate lithology, which exhibits fragility and poor mechanical properties (Yingtao et al., 2019). Precise prediction of wellbore instability and fluid loss in such formations is essential for efficient field development. The field of rock mechanics and wellbore stability has a long history, dating back to the early 20th century, when the first recorded studies focused on the stability of oil and gas wells (Cheatham, 1984).
- Asia > China (0.69)
- Europe > Norway > Norwegian Sea (0.24)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Rumaila Field > Zubair Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Rumaila Field > Shuaiba Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Rumaila Field > Nahr Umr Formation (0.99)
- (2 more...)
Prediction of In-Situ Stresses by Using Machine Learning and Intelligent Optimization Algorithms
Zhang, Haoze (Tsinghua University) | Wu, Bisheng (Tsinghua University) | Nie, Yuanxun (Tsinghua University) | Zhang, Xi (China University of Geosciences) | Chen, Zhaowei (CNPC Engineering Technology R&D Company Limited)
ABSTRACT In-situ stresses play an important role in affecting many geological processes such as hydraulic fracturing and CO2 storage, and a good understanding of the magnitude and direction of in-situ stresses is very important for deep energy exploitation. In this study, a machine learning model consisting of generative adversarial networks (GAN), particle swarm optimization (PSO) and support vector regression machine (SVRM) is proposed to predict the minimum in-situ horizontal principal stress (Shmin) from a series of existing experimental breakout data. First, the GAN and PSO are used to improve the quantity and quality of training data and to optimize the hyperparameters of the SVRM. Second, the enhanced training data are used to train the SVRM that predicts the Shmin based on the wellbore breakout geometries. In order to examine the reliability of this technique, the Shmin predicted from the proposed model is compared against the experimental data and it is found that the proposed model has a high accuracy with an average relative error of less than 10%. In addition, the proposed model requires only a few seconds to run on a laptop computer, thus providing a useful tool for accurate and efficient prediction of the Shmin. INTRODUCTION In-situ stresses play an important role in affecting many geological processes such as hydraulic fracturing and CO2 storage, and a good understanding of the magnitude and direction of in-situ stresses is very important for deep energy exploitation. During exploiting unconventional petroleum resources, drilling of a well and its stability depend on accurate measurement of in-situ stresses. Once the stress concentration at the borehole wall exceeds the rock strength, borehole failure occurs. In addition, in-situ stresses are closely related to earthquake faulting, volcanic eruptions and other geotechnical or geological processes. As a result, accurate measurement of in-situ stresses is of great significance.
- Asia > China (0.47)
- North America > Canada (0.46)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics > Earthquake (0.54)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Evolutionary Systems (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Statistical Learning > Support Vector Machines (0.71)