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10 December 2024, Volume 46 Issue 6

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A Special Issue of Efficient Exploration & Development Technologies for New Types Shale Gas of the Lower Cambrian Qiongzhusi Formation, Southern Sichuan Basin

New Type Shale Gas Exploration Discovery and Enlightenment of the Lower Cambrian Qiongzhusi Formation in the Southern Sichuan Basin

GUO Tonglou, XIONG Liang, HE Jianhua, WEI Limin, YAN Liang

2024, 46(6):  1-14.  DOI: 10.11885/j.issn.1674-5086.2024.11.20.29

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The Longmaxi Formation in the Sichuan Basin has a cumulative proven reserve of shale gas of 3$\times$10$^{12}$ m$^3$, with an annual production exceeding 250$\times$10$^{8}$ m$^3$. But the Qiongzhusi Formation, has just achieved commercial exploration discoveries and is currently undergoing exploration evaluation. Based on a comprehensive study of the characteristics of shale deposition, reservoir properties, geochemistry, fracability, and gas content in the Qiongzhusi Formation of the Cambrian System in southern Sichuan, along with extensive basic experimental data and a comparative analysis with the shale gas formation conditions in the Longmaxi Formation, the results indicate that the shale gas of the Qiongzhusi Formation exhibits significant differences from that of the Longmaxi Formation in terms of depositional environment, hydrocarbon generation capacity, storage space, gas content, mineral composition, and fracability, representing a new type. This new type of shale gas predominantly develops in trough-and-platform depositional systems, with strong hydrothermal activity, diverse hydrocarbon-generating organisms, and high hydrocarbon generation capacity. The storage space is dominated by inorganic pores, with organic pores serving as a beneficial supplement. The high content of feldspar and quartz minerals contributes to its overall good fracability. Comprehensive predictions suggest that the Mianyang—Changning trough is a favorable zone for shale gas in the Qiongzhusi Formation. Multiple wells in the Ziyang, Jingyan, and Weiyuan areas have achieved high-yield industrial gas flows, confirming that shale, ranging from deepwater to shallow water and from high to low TOC, can be enriched and form reservoirs. These areas are key regions for the exploration and development of this new type of shale gas. The research findings not only enrich the theoretical foundation of shale gas exploration and development but also establish a series of supporting exploration technologies, providing important demonstrative significance for shale gas exploration and development in different formations and regions.

Sedimentary Patterns and Depositional Systems of the Lower Cambrian Qiongzhusi Formation in the Southern Sichuan Basin

XIONG Liang, ZHONG Yijiang, DONG Yixin, PENG Minghong

2024, 46(6):  15-31.  DOI: 10.11885/j.issn.1674-5086.2024.11.16.15

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Recent advancements in shale gas exploration of the Qiongzhusi Formation in the southern Sichuan suggest that this interval has the potential to become a significant successor to the Wufeng-Longmaxi shale gas play. The shale sequences exhibit uneven lateral distribution, with notable variations in sedimentary facies characteristics, which pose challenges to further exploration and development. Drawing on the latest advances in fine-grained sedimentology, along with new drilling, well logging, and seismic data, this study analyzes the lithology, geochemistry, and sedimentary fabric of fine-grained sediments to elucidate sedimentary patterns, depositional environments, and sedimentary system development. The results indicate that: 1) synsedimentary fault activity led to the formation of a north-south-trending groove facies area in central Sichuan and the Exi-Yudong Region, generating a sedimentary deep-water gentle slope pattern characterized by "three platforms and two troughs". 2) controlled by the Mianyang-Changning groove facies area, a coastal-shelf-basin sedimentary system was established in southern Sichuan, with four subfacies: shallow-water gentle slope, deep-water gentle slope, steep slope and trough-basin. The Jingyan and Ziyang areas are dominated by shallow-water gentle slope and deep-water gentle slope subfacies, respectively. 3) fine-grained sediments sourced from the west were modified by storm currents, turbidity flows, and bottom currents, forming shallow-water gentle slope turbidites, bottom-current mounds, and deep-water gentle slope turbidites microfacies. 4) we established the sedimentary model based on fine-grained sedimentology and sedimentary patterns, providing crucial insights for the exploration of new shale gas plays within the Qiongzhusi Formation.

Sequence Stratigraphy of the Cambrian Qiongzhusi Formation and Its Control over Reservoirs in Southern Sichuan Basin

TANG Jianming, WANG Tong, ZHOU Hua, LUO Sicong, ZHOU Jing

2024, 46(6):  32-44.  DOI: 10.11885/j.issn.1674-5086.2024.11.18.53

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Currently, breakthroughs have been made in two exploration targets of the Qiongzhusi Formation in the Sichuan Basin (organic-rich shale and organic-lean shale), demonstrating good exploration potential. To clarify the sequence development pattern and its control on reservoir quality, this study utilized outcrop-drilling-seismic data, geochemistry, paleobiology, and other information to identify five third-order sequence boundaries and four third-order sequences within the Qiongzhusi Formation shale strata in the southern Sichuan Region. SQ1 corresponds to the bottom of the first member of the Qiongzhusi Formation, distributed only in the core of the intracratonic sag; SQ2 and SQ3 correspond to the upper part of the first member and the second member of the Qiongzhusi Formation, distributed on the western side and within the intracratonic sag; SQ4 corresponds to the third member of the Qiongzhusi Formation, widely distributed across the entire intracratonic sag. The sequence filling succession reflects the process of gradual filling and leveling the intracratonic sag. The transgressive systems tract (TST) is characterized by the development of black shale with high total organic carbon, high brittleness, and relatively high porosity. The deposition thickness is large within the intracratonic sag and gradually thins towards both sides. The regressive systems tract (RST) is dominated by organic-lean shale with strong heterogeneity. Only the RST of SQ3 on the western side of the intracratonic sag exhibits high porosity and brittleness, with good gas test results. This research holds significant guidance for predicting favorable exploration targets within the sequence framework.

Shale Sedimentary Environment and Development Model in the Groove Facies Area of Lower Cambrian Qiongzhusi Formation in the Central and Western Sichuan Basin

WEI Limin, FENG Shaoke, GU Zhanyu

2024, 46(6):  45-60.  DOI: 10.11885/j.issn.1674-5086.2024.11.18.03

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Significant breakthroughs have been made in the exploration of two types of shale gas, poor and rich in organic matter, in the Qiongzhusi Formation of the groove facies area in the Sichuan Basin. However, the degree of organic matter enrichment, shale gas reservoir characteristics, and formation conditions are significantly different from those of the Longmaxi Formation. Through comprehensive analysis of the lithology, grain size, mineral composition, organic carbon content, hydrocarbon generating organisms, and trace elements of the shale in the groove facies area of the Qiongzhusi Formation, we clarify the structural pattern of the "two platforms sandwiching one trough" in the central and western parts of the Qiongzhusi Formation during the Early Cambrian. The unique extensional tectonic background constructed a relatively stable semi open and semi closed environment for the sedimentation of the Qiongzhusi Formation shale. The high accommodation space and abundant input of terrestrial debris have laid the material foundation for the widespread development of the Qiongzhusi Formation silty shale. The changes in sedimentary water bodies and microfacies during the Qiongzhusi period in the Jingyan and Ziyang areas are the main reasons for the alternating development of two types of shale: poor organic matter and shale with rich organic matter. Therefore, a shallow water subfacies and deep water subfacies shale development model for the Qiongzhusi Formation in the groove facies areaa of the Sichuan Basin has been established, which has important reference value and guiding significance for the exploration of new types of shale gas under the background of extensional structures.

Lithofacies Identification in Deep Shale Reservoirs Via Neural Network Clustering Analysis: A Case Study of the Qiongzhusi Formation in the Southern Sichuan Basin

DONG Xiaoxia, FENG Shaoke

2024, 46(6):  61-73.  DOI: 10.11885/j.issn.1674-5086.2024.10.31.01

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With the significant breakthrough in shale gas exploration of the Lower Cambrian Qiongzhusi Formation by SINOPEC Southwest Oil and Gas Company, the hot spot of marine shale gas exploration in Sichuan is gradually shifting from the Longmaxi Formation to the Qiongzhusi Formation. Therefore, how to accurately identify shale lithology is a difficult problem that needs to be solved in current exploration work. To address this issue, based on the Total organic matter content and XRD experimental results of core samples, the deep shale reservoirs of the Qiongzhusi Formation were divided into five lithofacies (organic rich silty shale, organic rich calcium containing silty shale, organic poor silty shale, organic poor calcium containing silty shale, and organic poor clayey shale). Based on the triangulation of lithofacies and analysis of lithofacies characteristics, a workflow and model for identifying lithofacies in deep shale gas reservoirs were established using neural network clustering analysis theory. The confusion matrix results of the testing, validation, and training datasets were all greater than 88%, indicating high recognition accuracy. The identification of lithology in Well Z2 using its model is more accurate and efficient than traditional lithology methods, which is helpful for the efficient development of deep shale gas reservoirs in the study area and provides new ideas for lithology identification research in deep ultra deep shale gas reservoirs.

Pore Connectivity and Oil and Gas Filling Characteristics of Shale Reservoirs in the Qiongzhusi Formation, Southern Sichuan

SHI Hongliang, DENG Mingquan, ZHOU Hua, HE Jianhua, XU Hao

2024, 46(6):  74-90.  DOI: 10.11885/j.issn.1674-5086.2024.09.13.01

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Qiongzhusi Formation in southern Sichuan is rich in shale gas resources, demonstrating significant exploration potential. However, the characteristics of reservoir pore connectivity and the mechanism of oil and gas injection remain unclear. This article studies the pore structure and connectivity characteristics of the Qiongzhusi Formation shale in the study area based on high-pressure mercury injection, low-temperature N$_2$ adsorption, and FIB-SEM experiments. Additionally, the hydrocarbon injection capacity in the Ziyang-Jingyan Area will be investigated in conjunction with shale hydrocarbon generation kinetics simulation. The research indicates that: 1) the organic rich shale layer in the Qiongzhusi Formation of the Jingyan Area has poor pore connectivity, with a pore connectivity rate of 32.8%. However, it has a large hydrocarbon generation and pressurization scale, with a maximum cumulative overpressure of 48.50 MPa. On the other hand, the silty shale layers have good pore connectivity, with a pore connectivity rate of 55.7%, and a hydrocarbon generation and pressurization of 31.60 MPa; 2) the scale of hydrocarbon generation and boosting in the Qiongzhusi Formation shale in Ziyang Area is 1.3$\sim$1.9 times that of well research, reaching up to 62.80 MPa. Fluid inclusion testing shows a reservoir pressure of 60.00 MPa, which is consistent with this; 3) through the simulation of oil and gas injection dynamics, it was found that the oil and gas in the trough (Ziyang) increased significantly in the early and middle stages of hydrocarbon generation, reaching up to 56.50 MPa, and migrates towards the slope area (Jingyan); in the late stage of hydrocarbon generation, the burial depth of shale increases, the injection resistance increases, and the injection dynamics cannot overcome the resistance. The Jingyan Area is characterized by in-situ organic matter direct cracking for hydrocarbon supply.

Pore Structure Characteristics and Main Controlling Factors of Qiongzhusi Formation Shales of Lower Cambrian, Southern Sichuan Basin

LUO Sicong, ZHANG Nanxi, WANG Baobao, ZHOU Hua, WANG Tong

2024, 46(6):  91-106.  DOI: 10.11885/j.issn.1674-5086.2024.12.05.04

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To assess the characteristics and differences of the two types of shale reservoirs within the Qiongzhusi Formation of southern Sichuan Basin, based on the systematic coring data from drilling, a comprehensive application of experimental methods such as X-ray diffraction, argon ion polishing scanning electron microscopy, high-pressure mercury intrusion, low-temperature N$_2$ and CO$_2$ adsorption was employed to conduct research on the TOC content, mineral composition, microscopic pore types, pore structure characteristics, and their influencing factors of the two types of shale reservoirs. The research results indicate that both types of shale reservoirs develop multiple types of microscopic pores, and the overall pore type is mainly inorganic pores. The proportion of organic pores in the organic-rich shale is higher than that in the shale with organic matter. The porosity of the organic-bearing shale (TOC < 1%) ranges from 4.78% to 6.02% (average 5.22%), and the pore size distribution of the reservoir is mainly 20$\sim$100 nm, with macropores being the main reservoir space (average 70.10%). The porosity of the organic-rich shale (TOC $\geqslant$ 1%) ranges from 3.88% to 7.06% (average 5.53%), and the pore size distribution of the reservoir is mainly 1$\sim$50 nm, with mesopores being the main reservoir space (average 81.81%). The specific surface area and volume of micropores in the organic-bearing shale have a positive correlation with the TOC content, while the specific surface area and volume of micropores and mesopores in the organic-rich shale have a positive correlation with the TOC content. The relationship between the two types of shale reservoirs and the mineral composition is complex. The supporting structure constructed by quartz and feldspar lays the foundation of the original inorganic pores, and TOC, clay minerals, and post-diagenetic minerals filling the intergranular pores change the pore structure, and the increasing content of TOC can improve percentage of organic pores.

A Study on the Prediction Model and Application of the Diverting Capacity of Composite Proppants

GUO Jianchun, MA Jian, ZENG Fanhui, MU Kefan, ZHAO Zhihong

2024, 46(6):  107-114.  DOI: 10.11885/j.issn.1674-5086.2024.11.12.02

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This paper develops a comprehensive prediction model for the diverting capacity of propped fractures using an improved Kozeny-Carman equation, incorporating factors such as proppant grain size composition, elastic-plastic deformation, embedment, and creep. The study reveals that fracture diverting capacity decreases by approximately 54% from the 100th to the 1000th day under an effective closure stress of 60 MPa. The presence of larger grain-sized proppants enhances the diverting capacity, especially at lower effective closure stresses. The addition of small grain-sized proppants can reduce the decline in capacity under higher stresses. A higher elastic modulus of the proppant or fracture wall correlates with less deformation and embedment, leading to greater diverting capacity. Additionally, larger initial fracture widths and increased proppant layering can improve capacity by minimizing embedment effects. The model also indicates that over time and with increased effective closure stress, fracture width and diverting capacity will gradually decrease due to creep.

Practice of Multi-domain Fracture Fracturing in Ultra Deep Shale Gas

LIN Yongmao, MIAO Weijie, WANG Xingwen, CI Jianfa, DENG Yiping, LIU Lin, QIU Ling

2024, 46(6):  115-128.  DOI: 10.11885/j.issn.1674-5086.2024.11.26.01

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The Lower Cambrian Qiongzhusi Formation shale gas is the second shale reservoir capable of large-scale development after the Silurian Longmaxi Formation shale gas. The Qiongzhusi Formation in Ziyang Area is generally buried at depths greater than 4 500 m, with some exceeding 5 000 m, and belongs to a typical ultra deep shale gas reservoir. Unlike the Longmaxi Formation's deep shale gas, the fracturing of Qiongzhusi Formation's shale is faced with difficulties of ultra high pressure and low complexity fractures due to its high stress gradient and under-developed large-scale fractures. This article proposes a multi domain fracture fracturing technology to address the above difficulties, based on geological multi-scale fracture identification and engineering corresponding fracture multi domain communication. By using multiple methods to finely characterize and identify micro lithological cracks, honey points can be found in sweet spots. Seismic-geological-engineering integrated simulation software carries out full 3D numerical modeling to track hydraulic fracturing propagation, and variable density segmented clustering and 22 m$^3$/min communication of wide area large-scale cracks are proposed. Based on the complexity experiment of the physical model, multiple temporary blockages+pump stop temporary blockages are proposed to promote the expansion of lithological microcracks, matched with 140 MPa and high-strength construction scale, breaking through the barrier and support of ultra deep, multi-type, and multi-domain crack channels. The successful application of this technology in Well ZY2 has achieved a breakthrough in ultra deep shale gas fracturing, creating multiple records in construction displacement, construction scale, and temporary plugging strength, effectively ensuring the exploration breakthrough of the Qiongzhusi Formation in Ziyang Area and providing new ideas for ultra deep shale gas fracturing technology in the region.

Determination Method of Effective Permeability Based on Imbibition for Shale Reservoir

ZENG Fanhui, JIANG Jing, MA Jian, GUO Jianchun, MU Kefan

2024, 46(6):  129-136.  DOI: 10.11885/j.issn.1674-5086.2024.11.12.03

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Effective permeability is one of the key parameters to characterize shale reservoirs. Due to the density of shale reservoir, it is of great difficulty to obtain the effective permeability through by core flow experiment. In order to solve the problem, a method to predict the effective permeability of rock based on imbibition experiment is established in this paper. Firstly, the spontaneous imbibition coefficient is obtained through shale spontaneous imbibition experiment, and the effective permeability prediction method based on the spontaneous imbibition coefficient is established by comprehensively considering the permeability pressure, tortuosity and dynamic capillary force of shale. The results show that the effective permeability prediction method established in this paper takes into account all factors, requires fewer parameters, and has a clear calculation process, which is more in line with the real formation situation. Osmotic pressure and tortuosity have obvious influence on effective permeability. Ignoring osmotic pressure will lead to a higher prediction of effective permeability, and ignoring tortuosity will lead to a lower prediction of effective permeability. This paper provides a new way to evaluate effective permeability of shale reservoir effectively and quickly.

Optimization of Dynamic Fracture Plugging Parameters in Lower Cambrian Qiongzhusi Shale, Southern Sichuan Basin

LI Yongming, MA Jian, LI Tiefeng, SUN Peng

2024, 46(6):  137-145.  DOI: 10.11885/j.issn.1674-5086.2024.12.12.01

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Horizontal well staged multi-cluster fracturing is a key technology in the exploration and development of shale gas reservoir. In order to ensure the uniform expansion of multi-cluster fractures, temporary plugging ball is used to seal the advantageous fractures. In order to improve the sealing efficiency, we simulates and analyzes the migration and sealing process of temporary plugging balls in horizontal wells based on a visual wellbore temporary plugging experimental device, to understand the impact of improving the efficiency of seam sealing. Based on the Fannin equation, flow friction and fracturing process, the hole diameter model was established and the dynamic sealing parameters were optimized. The results show that when the diameter of temporary plugging ball is 1.03 times of the hole diameter and the number of temporary plugging ball is 1.1~1.3 times of the opening number of the hole, the setting efficiency of the hole after abrasion is the highest. The plugging efficiency of Well Jinye 3 in Qiongzhusi Shale was significantly improved, and the pressure of each section increased significantly after the temporary plugging, which provided a theoretical method for the optimization of the multi-cluster fracture plugging process of similar shale oil and gas horizontal wells.

Technology and Application of Safe and Efficient Shale Gas Drilling in the Qiongzhusi Formation of Jingyan-Qianwei Area, Southern Sichuan

LUO Chengbo, ZHOU Xingfu, OU Biao, LIU Wei, ZHANG Shengjun, ZHANG Yusheng, WANG Zhiguo

2024, 46(6):  146-154.  DOI: 10.11885/j.issn.1674-5086.2024.11.18.02

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The Jingyan-Qianwei Area has developed various structures such as stretching, compression, and strike slip, with overall crack development. The southwest of the areas is characterized by multiple intersecting faults and complex fractures. The drilling process of exploratory wells deployed in the early stage mainly faces the following challenges: There are many leakage points in the formation, difficulties in quick inclination prevention in straight sections and in well trajectory controling; the mechanical drilling speed is slow. In order to safely and efficiently explore and develop shale gas in this block, a safety drilling technology has been developed with the optimization of differentiated three opening wellbore structure, integrated geological engineering track design to avoid fracture solution, pressure drop density control technology to control complex overflow and leakage, and multi-stage high-efficiency plugging technology as the core. The key to this technology is the anti collapse drilling fluid system, integrated drilling parameters of drill bits and drilling tools, and four in one geological guidance. Technology integration is applied to 9 wells, with an average drilling encounter rate of 100% for high-quality reservoirs, an average drilling speed of 1.9 m/h to 8.6 m/h, and a drilling cycle of 233 d to 72 d. Practice has shown that the formed safe, efficient and fast drilling technology not only provides technical support for safe and efficient exploration and development, but also provides technical guarantees for increasing storage and ore preservation, as well as sustained and stable production.

Optimization and Evaluation of Slimming Wellbore Structures for the Qiongzhusi Formation of Jingyan-Qianwei Area, Southern Sichuan Basin

HE Long, HE Xinxing, ZHANG Yusheng, YAN Yancheng, LIU Wei, ZHU Liping

2024, 46(6):  155-164.  DOI: 10.11885/j.issn.1674-5086.2024.12.16.02

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There are some issues in the upper strata of Qiongzhusi Formation of Jingyan-Jianwei Area, southern Sichuan Basin, such as complex pressure systems, wellbore instability, and poor drillability, etc, which lead to prolonged drilling cycles and high well construction costs. To deal with these issues, we established the tri-pressure profile and complex formation sections in the Jingyan-Jianwei Area by analyzing data of drilled wells. The necessary sealing points for the first and second were optimized, and a conventional wellbore structure scheme for this region was formulated. Based on the goal of cost reduction, a slimming scheme with a $\phi$190.5 mm wellbore for well completion was proposed. Through hydraulic and pipe string mechanical analyses, the adaptability evaluation of the slimming wellbore structure was conducted. For single-well implementation, the first and second spuds of the slimming structure well employ $\phi$127.0 mm drill pipes, and the third spud adopts $\phi$127.0 mm+$\phi$114.3 mm drill pipes. For platform well, the first and second spuds of the slimming structure well utilize $\phi$139.7 mm drill pipes, and the third spud adopts $\phi$127.0 mm+$\phi$114.3 mm drill pipes. When the well deviation angle is less than or equal to 90°, a horizontal well with a horizontal section length of 3 000 m can be implemented. By applying the conventional wellbore structure scheme, the actual drilling cycle was shortened by 21.68% compared to the previous stage. If the slimming wellbore structure is adopted, it is expected that the cost of a single well can be reduced by 1.8 million yuan. The research and technical achievements can offer significant optimization directions for the subsequent drilling engineering design of the Qiongzhusi Formation shale gas, and are anticipated to reduce the well construction costs, facilitating the efficient development and large-scale production of shale gas resources in the Qiongzhusi Formation of Jingyan-Jianwei Area.

Mechanism and Preventive Measures of Casing Deformation in Shale Gas Wells of Qiongzhusi Formation in Jingyan-Qianwei Area

ZHANG Guodong, XIA Biao, LI Youpei, LI Shuguang, MU Kefan, WANG Zhiguo, LU Li

2024, 46(6):  165-176.  DOI: 10.11885/j.issn.1674-5086.2024.12.05.05

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Jingyan-Qianwei Qiongzhusi has a huge amount of silty shale gas resources. The target layer in this area has a large burial depth, complex geological structure, and high horizontal stress values in the reservoir. Some wells experienced severe casing deformation during the fracturing process, resulting in lost sections and seriously affecting single well production. Based on the characteristics of casing deformation failure and the analysis of common engineering and geological influencing factors in the deformed well section, a numerical simulation model of formation casing cement ring fracturing was established to clarify the mechanism of casing deformation. A set of risk assessment methods for casing deformation is established based on critical injection pressure, formation stress state, and corresponding fracturing fracture state. The risk of casing deformation is classified, forming a balanced fracturing and casing deformation prevention technology system of "fine optimization+real-time warning+three control mode". The technology is finely segmented, and real-time warning is used through microseismic monitoring. The risk section controls the scale, displacement, and operation rhythm. The application results show that the technology system can effectively reduce the occurrence of casing deformation and provide technical support for the development of the area's benefit scale.

Leakage Prevention and Plugging Technology of Shale Gas Well of Lower Cambrian Qiongzhusi Formation, Southern Sichuan

YAN Yancheng, TANG Tao, ZHANG Shengjun, WANG Zhiguo, HE Miao, HE Xinxing

2024, 46(6):  177-186.  DOI: 10.11885/j.issn.1674-5086.2024.12.19.01

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The Cambrian Qiongzhusi Formation shale gas resources in southern Sichuan are 2 206$\times$10$^8$ m$^3$, which is an important area for increasing natural gas reserves and production in the Sichuan Basin. The geological structure of the block is complex, with karst caves and large fractures developing in the upper strata, dissolution fractures and caves developing in the middle marine strata, and faults, folds and dissolution fractures developing in the lower strata, resulting in different types of leaks from the surface of shale gas wells in southern Sichuan to the target layer. Well leakage occurs rapidly, with large leakage volume and long processing time. In response to the above problems, an analysis of well leakage characteristics was carried out. With the geological engineering integrated leakage prevention and plugging that combines avoidance, prevention and plugging as the guiding idea, the leakage characteristics of each formation were carefully analyzed. Through technical idea adjustment, key material research and selection, indoor system optimization experiments and field application iterative upgrades, we have formed a geological engineering integrated track design based on seam and hole prediction and leakage prevention technology by improving formation pressure bearing capacity while drilling, non-return lost circulation broad-spectrum bridge slurry plugging technology, loss-returning lost circulation composite plugging technology and reservoir temperature control solidification. Using knotted leakage plugging technology, an integrated leakage prevention and plugging technology system for hierarchical classification prevention and control of shale gas wells in the Qiongzhusi Formation has been constructed. The application results show that the lost circulation control time is reduced by 65%, providing technical support for the efficient development of shale gas in the Qiongzhusi Formation.