Journal of Southwest Petroleum University(Science & Technology Edition)

Research on High Water Absorbent Resin for Leak Prevention and Sealing in Water-based Drilling Fluid

LUO Pingya, DAI Feng, LIU Yingmin, HE Jianing, BAI Yang

2025, 47(4): 1-9. DOI: 10.11885/j.issn.1674-5086.2024.07.03.02

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To address the problem of wellbore leakage caused by clay particles and natural fractures in shale oil and gas reservoirs using water-based drilling fluids, which cannot be successfully plugged, acrylic acid and polyvinyl alcohol are used as monomers, N, N'-methylene bisacrylamide is used as a chemical crosslinking agent, and the response surface method is adopted with water absorption rate as the response target. The experimental factors are optimized, and a PAA/PVA interpenetrating network structure high water absorbent resin plugging agent is prepared through free radical solution polymerization. The successful synthesis and thermal stability of the plugging agent were verified by infrared, thermogravimetric, and scanning electron microscopy analysis. Evaluate the pressure sealing performance of the plugging agent through sealing and pressure bearing capacity experiments, sand bed experiments, and micro crack simulation experiments. The test results show that the plugging agent has good thermal stability. Under the conditions of a fracture width of 2 mm, a temperature of 180 ℃, a plugging agent dosage of 3%, and a confining pressure of 10 MPa, the maximum pressure bearing capacity is 6.08 MPa, and the high-temperature and high-pressure filtration loss is 9 mL. It can achieve the plugging effect of water-based drilling fluid in shale formations.

Complex Fluid Identification Method for Ultra Deep Heterogeneous Low Porosity Sandstone Reservoirs

ZHAO Yuanliang, YU Bing, GUO Kecai, WANG Meiling, SHUAI Shichen

2025, 47(4): 10-22. DOI: 10.11885/j.issn.1674-5086.2023.11.26.01

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The burial depth of Cretaceous Bashkirchik Formation in Bozi-Dabei area of Kuqa Depression, Tarim Basin is more than 6 000 m, and the porosity is mainly distributed between 6%~9%. At the same time, the complex pore structure, significant changes in regional formation water mineralization and geostress result in low contrast in electrical resistivity between gas and water layers. The poor physical properties of the matrix result in poor applicability of non electrical fluid identification methods such as array acoustic rock mechanics parameters and neutron-density envelope. A detailed analysis of regional geological characteristics was conducted to address the identification problem of low contrast in gas and water layer resistivity in the Bozi-Dabei Region, and three electrical identification methods have been developed, including the precise establishment of porosity resistivity intersection diagram method in stress zones, pure water layer resistivity inversion method, and adjacent mudstone resistivity comparison method. At the same time, a non electrical identification method for two-dimensional nuclear magnetic T₁-T₂ intersection map that is not affected by the skeleton was introduced. This fluid identification method was applied to the tracking and interpretation of exploration wells in the Bozi-Dabei Area, interpretation coincidence rate increased by 16.7%, effectively solved the difficulty of fluid identification caused by low contrast of gas and water layer resistivity due to complex geological conditions in the Bozi-Dabei Region. It provides a powerful technical means to avoid oil and gas reservoir leakage in the study area. It has important application and popularization significance in the domestic ultra-deep tight sandstone reservoirs such as the southern margin foreland basin of Junggar, Xinjiang and Hetao Basin of Huabei Oilfield.

Characteristics of Full-frequency Bentonite of Ordovician–Silurian Transition in Southeastern Sichuan and Its Significance Indicator of Shale Gas

LI Boshuo, SHAN Chang'an, LIANG Xing, GU Xiaomin, HE Fangyu, SHI Hailong

2025, 47(4): 23-40. DOI: 10.11885/j.issn.1674-5086.2024.01.11.02

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In the shale of the Wufeng-Longmaxi Formation in the southeastern Sichuan Basin, there are several sets of bentonite beds, which keeps records of key information about numerous geological events. In order to clarify the characteristics of bentonite development and its significance for shale gas, core observation, thin section identification, SEM observation, whole rock X-ray diffraction have been carried out for the core of several shale gas evaluation exploration wells and typical sections in neighboring areas in southeastern Sichuan, and the following results have been obtained. 1) In the standard well of bentonite in southeastern Sichuan Province, 59 bentonite layers are identified, and were further divided into 6 sets of bentonite development segments. 2) In the process of volcanic ash deposition, the alkaline water environment chemically destroys the hard protein structure of graptolite, resulting in the phenomenon that graptolite does not develop in the surrounding rocks above and below the bentonite. 3) There are alteration phenomena in the bentonite, and the products are mostly pyrite. 4) Low-frequency and high-intensity development of bentonite often indicate high-quality shale, and high-frequency and high-intensity, highfrequency and low-intensity development of bentonite often indicate subprime-quality shale, while low frequency and low intensity development of bentonite is regarded as ordinary organic shale.

Difficulties and Key Acquisition Techniques in Seismic Exploration of the Qiongzhusi Formation in the Southern Sichuan Basin

DUAN Wenshen, WU Chaorong, TU Yuangen

2025, 47(4): 41-50. DOI: 10.11885/j.issn.1674-5086.2024.12.07.01

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The Qiongzhusi Formation of Lower Cambrian is widely distributed in the southern Sichuan Basin and is an important shale gas layer for exploration and development. This area has complex geological characteristics both on the surface and underground, facing seismic exploration challenges, such as large terrain undulations, exposed limestone on the surface, high and steep underground structures, multiple coal mine goafs, and low operation efficiency. After more than 10 years of research and practice, key technologies have been developed to solve the difficulties in seismic exploration of the Qiongzhusi Formation in the southern Sichuan Basin: 1) subdivision of the surface element acquisition and observation system, improving the coverage frequency and the aspect ratio of the main target layer, and effectively controlling the acquisition cost; 2) explosion techniques such as optimizing terrain, optimizing lithology, balancing excitation energy, and enhancing explosion coupling; 3) techniques for acquiring and controlling signals that optimize detector selection, detector positions, detector placement implementation, and noise control when receiving; 4) a supporting technology for improving the receiving effects of coal mine goaf through the analysis of lighting models and on-site experiments in coal mining area, which has improved the quality of data acquisition in goaf areas; 5) the promotion and use of node meters that have significantly improved the efficiency of data acquisition. The key acquisition techniques developed for the research have effectively solved the problem of shale gas seismic exploration in complex areas, collecting over 2 000 km² of 3D seismic data in five work areas, providing important technical support for shale gas exploration and development.

Characteristics and Distribution of Lower Paleozoic Weathering Crust Reservoir in Binchang Area

LIU Ling, LENG Jiaxuan, ZHANG Juntao, YANG Fei, YUAN Chunyan

2025, 47(4): 51-61. DOI: 10.11885/j.issn.1674-5086.2023.12.01.01

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The Lower Paleozoic weathering crust karst reservoir in Binchang Area of southern Ordos Basin has good exploration prospect, which is an important area for achieving petroleum breakthrough and increasing reserves and production in the future. However, the exploration in the area is not adequate, the weathering crust karst reservoir not been systematically studied, and the development characteristics and distribution law of the reservoir unclear. This seriously restricts the further exploration. Based on drilling and seismic data, the development characteristics and the main controlling factors of the weathering crust karst reservoir had been analyzed. In addition, the reservoir development model had been established and its distribution law had been predicted. The research showed that reservoir lithology mainly includs oolitic dolomite, oolitic limestone, slit-fine-grained dolomite and argillaceous dolomite. The reservoir space was dominated by dissolution pores and fractures, and intercrystalline pores could be seen. Paleogeomorphology and faults were the main controlling factors of reservoir development. High-quality reservoirs mainly developed in the dissolved hills where faults developed. Considering the main controlling factors and plane distribution of weathering crust karst reservoir, Binchang area can be divided into four types of reservoir areas. Type I was the most favorable area for reservoir development, which related to Caledonian faults and has large distribution. The faults had strong influence on it. The reservoir quality was good. Type II was a first-level reservoir development area, which was distributed near the minor strike-slip fault in NW direction. The fracture had little influence on karst and the distribution of karst reservoirs was limited. Type III was a relatively developed reservoir area, which was related to Paleozoic fractures and had little influence on karst, and the weathered crust karst reservoirs were scattered. Type IV was a disadvantageous reservoir area, which was related to the large linear faults formed by the Yanshan-Himalayan tectonic movement. It had a large scale. Due to its location, there was serious denudation and the reservoir quality was poor.

A Logging Interpretation Method for Tight Sandstone Diagenetic Facies Based on Improved SMOTE and Random Forest Algorithm

ZHEN Yan, KANG Jintao, ZHAO Xiaoming, GE Jiawang, DAI Maolin

2025, 47(4): 62-74. DOI: 10.11885/j.issn.1674-5086.2022.05.04.01

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Diagenetic logging interpretation is the key to predict high-quality tight sandstone reservoirs. Compared with conventional mathematical statistical methods, machine learning methods can effectively improve the accuracy of diagenetic facies logging interpretation. However, due to the insufficient number of samples, there are still some multi-solutions in the interpretation results. In order to effectively solve the problem of sample data imbalance in the logging interpretation of diagenetic facies, this paper considers the spatial constraints of new samples on the basis of the classical SMOTE (Synthetic Minority Over-sampling Technique) algorithm. This paper puts forward a RESMOTE (Repeat SMOTE) algorithm, which adds the few class samples in the imbalanced data, and uses the random forest model to identify and explain the diagenetic facies. The experimental results show that the RESMOTE algorithm is better than classical SMOTE algorithm, Borderline-SMOTE algorithm and ADASYN algorithm, and the accuracy of random forest model is improved from 77.27% to 91.06%. The RESMOTE algorithm can ensure the accuracy of new data, effectively solve the problem of over-fitting and low accuracy in conventional logging lithofacies identification and classification methods, and has important application value for the prediction of high quality tight sandstone reservoirs.

The Influence of Differences in Pore Structure of HY Gas Field Reservoir in Xihu Depression on Its Permeability Characteristics

DUAN Dongping, LIU Binbin, PANG Yu, SHI Qiong, LI Wenjun, TANG Hongming

2025, 47(4): 75-86. DOI: 10.11885/j.issn.1674-5086.2024.04.12.04

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Accurate characterization of microscopic pore structure is the key to evaluating reservoir resources and productivity. Taking the low-tight permeability sandstone reservoir of the Huagang Formation in the HY Gas Field of the Xihu Depression as an example, pore structure parameters are characterized on a full-scale basis by combining low-pressure nitrogen adsorption, high-pressure mercury injection, and nuclear magnetic resonance technology. Combined with the steady-state gas-water relative permeability and movable fluid saturation experiments, the reservoir seepage mechanism and control factors are comprehensively evaluated. The results show that the proportion of dissolved pores in reservoir samples increases, and the pore size decreases gradually from type I to type IV reservoirs in the study area. The proportions of pore throats with radius greater than 1 μm are 50.7%, 41.3%, 25.2% and 5.7%, respectively. With the deterioration of pore structure quality, the gas-water relative permeability curve in the study area shifts to the right, and the irreducible water saturation ranges from 15% to 55%. The effective permeability of the gas phase ranges from 0.01 to 9.00 mD, and the water saturation in the range of gas-water co-seepage is 6%~65%. When the flowback pressure gradient is 9 MPa/m, the average movable fluid saturation of the reservoir exceeds 50%, and the pore throat connectivity is good. The water film occurs in the pore throat radius μm. The reservoir seepage capacity is worse where a larger proportion of the water film. The research results have significant guidance for formulating effective development countermeasures and predicting gas well productivity in this area.

Mechanism Analysis and Prospect of Efficient Production of Gas Drilling in Tight Sandstone Gas Reservoirs

LI Gao, ZHANG Yi, LI Hongtao, MENG Yingfeng, YANG Xu

2025, 47(4): 87-95. DOI: 10.11885/j.issn.1674-5086.2023.06.17.01

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Gas drilling for the development of tight sandstone gas reservoirs is of natural advantages in avoiding reservoir damage. However, the lack of clear understanding of its mechanisms introduces uncertainties regarding its ability to achieve efficient production. To address this issue, a systematic review was conducted on the experiences and lessons learned from gas drilling for the development of tight sandstone gas reservoirs. The gas drilling practices in the Dibei and western Sichuan regions were used as examples. Based on drilling monitoring data such as methane concentration and outlet humidity, and through the analysis of cuttings' X-ray diffraction and logging data, the mechanisms for efficient production were examined. The study revealed that productive gas points in high-yield wells corresponded to the height of the sandstone-shale lithological interface, confirming that the derived fracture network system serves as the primary gas storage space and gas production pathway, making it a crucial target for wellbore trajectory. Influenced by fault zones, water from the lower part of aquifers could migrate to the upper part of the fault drop zone. Therefore, well deployment should be based on high structural points and fault uplift zones, taking into account reservoir evolution and tectonic movement history for optimization. It is believed that further in-depth research in engineering geological mechanics is needed, focusing on the effectiveness of lithological interface fractures, the relationship between gas and water in aquifers, and their impacts. Additionally, the development of gas drilling and completion techniques and tools for complex environments should be pursued.

Numerical Well Testing Analysis of Multi-well Interference from Multi-fractured Horizontal Wells

HE Youwei, CHEN Zhangchi, TANG Yong, ZHAO Guoqing, WU Keyu

2025, 47(4): 96-112. DOI: 10.11885/j.issn.1674-5086.2023.09.08.02

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Interwell interference cannot be ignored especially in tight and unconventional oil and gas reservoirs since adjacent wells may be communicated through natural fractures or even hydraulic fractures due to tight well spacing. Currently, the well testing models are focused on an individual well with simple fractures. It lacks the well testing model considering multiple wells with complex fracture networks. It is necessary to develop the numerical well testing method of multi-well interference, and analyze the impact of adjacent wells and fracture network parameters on the pressure transient behavior of the observed wells. Thus, this work proposes a numerical well test model of multiple fractured horizontal wells with complex fracture networks. The accuracy and advantages of the proposed model are validated. The effect of well interference, adjacent well's production, nonuniform fracture aperture, fracture networks, fracture conductivity of hydraulic and natural fractures on the pressure transient behavior are analyzed. Well-developed natural fractures lead to better interwell connectivity, and the adjacent wells influence the fracture linear flow, fracture radial flow, elliptical flow, and final radial flow period. When the natural fractures are not well developed, the adjacent wells affect the middle and late pressure behavior of the observation well. The developed multiwell numerical well testing model in this work considers the complex fracture networks, irregular fractures, nonuniform gas production profile, and interwell interference, which can characterize early pressure behavior and pressure differences among matrix, fracture and other grids more clearly. It enriches the numerical well testing analysis method of tight and unconventional oil and gas reservoirs.

A New Production Splitting Method for Unconsolidated Sandstone Gas Reservoir with Water

WANG Guofeng, WANG Xiaolu, KUI Mingqing, ZHAO Hui, MIAO Miao

2025, 47(4): 113-120. DOI: 10.11885/j.issn.1674-5086.2023.02.20.02

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Production splitting is a prerequisite for the accurate description of multilayer gas reservoirs. However, KH method, mutation method, gas production profile test and other production splitting methods commonly used at present have some problems, such as low accuracy and no long-term dynamic production splitting. In order to solve the problems, the iterative calculation was carried out by combining the stress-sensitive productivity equation and the material balance equation considering the influence of water sealed gas, and automatic fitting method was used to fit the production history, the optimal fitting parameters were obtained, and A new production splitting method for unconsolidated sandstone gas reservoir with water was innovatively proposed. The results show that when laminar coefficient and turbulent coefficient of the combined production zone are different, the contribution rate curve presents an “X ” type trend; when dynamic reserves of the combined production zone are different, the contribution rate curve of production presents a “<” type trend; the greater the difference between laminar coefficient, turbulent coefficient and dynamic reserves, the greater the difference between production contribution rates. Through the case analysis of a gas well in Sebei-2 Gas Field, it is found that the research results show that the production splitting result for unconsolidated sandstone gas reservoir with water is similar to the test result of gas production profile (average error 4.70%), and the contribution rate of production can be obtained in real time.

A Numerical Study on Freeze-thaw Hydrate Reservoir Exploitation Induced by Fracturing Technology

HAO Guoqiang, HOU Jiaxin, DUAN Shuo, LI Xinwang, SHEN Pengfei

2025, 47(4): 121-136. DOI: 10.11885/j.issn.1674-5086.2022.11.25.01

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The formation of ice phase during the exploitation of natural gas hydrates in permafrost regions increases the difficulty of gas migration within the reservoir. Therefore, enhancing gas production and reducing ice formation to alleviate the blockage of gas migration in the reservoir are key issues for the efficient development of frozen-thawed hydrate reservoirs. Based on the reservoir parameters of the Well DK-2 in the Qilian Mountain permafrost region, this paper proposes a combined development strategy of depressurization and hydraulic fracturing. Through numerical simulation, the influence of the fracture radius (0~5 m) and permeability (1~1 000 mD) on the exploitation effect is systematically evaluated. The research shows that the modified reservoir area formed by hydraulic fracturing can effectively inhibit ice phase blockage and accelerate pressure transmission and gas migration. When the fracture radius increases from 0 m to 5 m, the cumulative gas production over 30 years increases by 219%, with a contribution rate of 54.8% in the first 10 years, and the overall reservoir decomposition rate is 48.7%. The parameter sensitivity analysis indicates that the production enhancement effect slows down when the fracture permeability exceeds 100 mD, and the optimal fracture radius is recommended to be 4 m. This research provides a theoretical basis for the engineering control of ice plugging effects in permafrost hydrate exploitation and reveals the significant role of reservoir modification in improving the efficiency of two-phase gas and water migration.

Adsorption Characteristics of Fluid in the Reservoir of Wells Injected Alternately by Supercritical Carbon Dioxide and Water

BAI Yujie, WEI Haodong, NAN Xiaohan

2025, 47(4): 137-145. DOI: 10.11885/j.issn.1674-5086.2022.06.21.02

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In order to study the adsorption characteristics of fluid in the reservoir of wells injected alternately by supercritical carbon dioxide and water, the microstructure and mineral composition of reservoir rocks were analyzed. The molecular model of stratum rock structure was established to study the fluid adsorption characteristics of different clay minerals, and the competitive adsorption and influencing factors of different fluids on the rock surface were analyzed. The results showed that the compact rocks of Yushulin oil layer in Daqing Oilfield are composed of silica matrix and clay minerals such as kaolinite and montmorillonite. The adsorption capacity of reservoir minerals for light hydrocarbons was greater than that for heavy hydrocarbons, and adsorption capacity for water and carbon dioxide was greater than that for hydrocarbons. Silicon dioxide had the strongest adsorption capacity for water and carbon dioxide, indicating that the oil recovery of the reservoir dominated by silicon dioxide was higher by using alternate injection flooding of supercritical carbon dioxide and water. Intermittent stop injection could make carbon dioxide easier to enter into rock samples and make crude oil easier to discharge. The higher temperatures accelerate the exchange of crude oil, water and carbon dioxide molecules. Under high pressure, carbon dioxide reacts with crude oil on the rock surface to change the properties of crude oil, thereby increasing the oil removal rate.

A New Model to Calculate Critical Velocity for Liquid Loading in Gas Wells

LUO Chengcheng, LI Nan, LIU Yonghui, CAO Guangqiang, YE Changqing

2025, 47(4): 146-154. DOI: 10.11885/j.issn.1674-5086.2023.08.13.31

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Accurately predicting the liquid-loading timing in gas wells and taking reasonable corresponding deliquification technologies in advance can effectively reduce the risk of liquid loading. Existing liquid-loading prediction models lack comparative analysis with liquid-loading features in gas wells, resulting in poor adaptability. Therefore, visual experimental tests were carried out to study the flowing behavior of liquid film at different gas velocities, a new criterion of liquid-loading initiation was defined subsequently. Based on the force balance of liquid film, an analytical model of critical gas velocity for liquid loading was established. And the following research results were obtained. First, the liquid does not accumulate at the bottom of the pipe when the liquid film reverses and travels upward as instead liquid waves. The more serious the liquid film reversal is, the more obvious the fluctuation is. Second, when the liquid film reverses, the flow is relatively stable in the pipe, which is not consistent with the features of liquid loading in gas wells, leading to the prediction of critical gas velocity in liquid-reversal criterion too conservative. Third, it captures the liquid-loading dynamics in gas wells when liquid-loading criterion is defined as the equal liquid flow rate of upward and downward in the laminar liquid film. Fourth, the new model has a good changing trend with the liquid-film model at different affecting parameters, and its prediction accuracy is the highest against the published well data in the literature. In conclusion, the new model can be used to judge liquid loading in gas wells.

A Study on the Control Law of Fluid Control Valve for Balanced Production in Horizontal Wells

XIAO Xiaohua, HAN Shuo, ZHAO Jianguo, WANG Guorong

2025, 47(4): 155-164. DOI: 10.11885/j.issn.1674-5086.2023.10.20.02

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Aiming at the technical problems of short life and low production of oil and gas wells caused by unbalanced production of horizontal wells, a new fluid control valve with trapezoidal orifice is proposed, and the maximum throttling pressure difference of the valve reaches 2.65 MPa. The flow pressure simulation model of multi-layer fluid control valve for horizontal well is established, which considers the throttling performance, installation size and formation pressure distribution of the new fluid control valve. It is found that in order to achieve balanced oil production, the opening of the fluid control valve gradually decreases from toe to heel. The greater the pressure difference of each layer, the smaller the opening of the fluid control valve. The pressure difference is between 0.01~0.10 MPa, and the maximum reduction of the opening of each layer is about 37.2%. The longer the distance between the fluid control valves in each layer, the greater the opening of the fluid control valve. The valve distance is between 100 m and 500 m, and the maximum increase of the opening in each layer is about 2.8%. The research results provide a theoretical basis for the optimization design of the production string structure of the fluid control valve in horizontal wells, the formulation of the production system, and the control of the opening of the fluid control valve, which is of great significance for promoting the popularization and application of the fluid control valve in horizontal wells.

Development and Application of A New Self-vibration PDC Bit

YAO Jianlin, QIAO Huotong, LIU Ke, HUANG Wei, LIU Bin

2025, 47(4): 165-176. DOI: 10.11885/j.issn.1674-5086.2023.12.23.31

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Due to the problems of serious back-pressure, large friction and torque fluctuation in the drilling of build-up section and horizontal section, the rock breaking WOB cannot be effectively applied, which results resulting in low ROP of conventional PDC bit run. By using tools such as hydraulic agitator, compound bit, certain effect on acceleration of ROP cannot be achieved, but well site drilling needs can not be fully met due to limitation of tool size, installation position and downhole safety of compound bit. Therefore, a self-vibration unit of compact structure is designed based on the principle of water hammer impact. A new ϕ215.9 mm self-vibration PDC bit is developed. Through theoretical calculation and CFD numerical simulation technology combined with key parameters such as vibration frequency and vibration force, a new ϕ215.9 mm self-vibration PDC bit is developed, which can produce low-frequency axial impact force directly acting on rock. The field application in well Yun'an X1 shows that the mutation frequency and variation range of the hook load of the new self-vibration PDC bit are significantly lower than those of the compound bit in the same section of the same well, which effectively reduces the friction between the drill string and the borehole wall and further alleviates the back pressure problem. Thus, the average ROP is increased by 32.97% in the same well compared to that of compound bit, and by 74.50% compared to that of the conventional PDC bit in the adjacent well, realizing the speed increase, cost reduction and efficiency increase.

Research and Application of Window Opening for High-grade Steel Thick-wall Casing in Ultra-deep Wells

TANG Ming, WANG Shuangning, HE Shiming, ZHANG Guangfu, LIU Xiaosen

2025, 47(4): 177-188. DOI: 10.11885/j.issn.1674-5086.2023.12.27.35

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Windowing and sidetracking is one of the important methods to deal with complex accidents underground. Windowing and sidetracking in ultra-deep wells such as not less than 7 000 m well depth with high steel grade (TP155V) and thick wall (15.83 mm) casing not only faces complex underground environment with high temperature and pressure, but also has the difficulty of long operation time and high cost. In order to improve the success rate and operation efficiency of high steel grade thick wall casing windowing in ultra-deep wells, this paper uses ABAQUS software to establish the casing windowing side-drilling simulation model and optimize the windowing milling cone. Ground tests are used to further demonstrate the simulation results, and the selected ones are suitable for the windowing milling cone in ultra-deep wells for field application. The simulation shows that the milling shoulder and the outer circle of the cone top are the main working faces of window opening and window repairing. The conical milling cone has the largest window opening stress, the highest window opening efficiency, and the regular and smooth shape of the window. In the ground test, the conical milling cone can successfully open the window, but the spiral milling cone and the drill type can't open the window successfully. The casing with a depth of 7 473 m, a wall thickness of 15.83 mm and steel grade TP155V was successfully drilled by conical milling cone in Well Shuangtan102, which set three records in China for the deepest drilling depth, the highest steel grade and the thickest wall thickness. The research results of this paper provide a reference for the efficient windowing and sidetracking of ultra-deep Wells, and provide support for the efficient exploration and development of ultra-deep oil and gas resources.

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