Milling bridge plugs in shale gas wells with severe casing deformation often leads to the accumulation of cuttings,increasing the risk of stuck drill bits.Friction in the wellbore further complicates tool deployment i...Milling bridge plugs in shale gas wells with severe casing deformation often leads to the accumulation of cuttings,increasing the risk of stuck drill bits.Friction in the wellbore further complicates tool deployment into the horizontal section,posing challenges to efficient plug drilling and achieving wellbore access to the target layer.This paper integrates the theory of positive displacement motors and models their actual working characteristics to study the milling of bridge plugs in severely deformed horizontal wells.It examines the effects of coiled tubing diameter and wall thickness on the bending load of horizontal sections and discusses key technical requirements,including the timing of plug drilling,extending the run in the horizontal section,parameter control,and real-time field analysis.Field practices have shown that after casing deformation occurs,priority should be given to drilling out the bridge plugs below the point of deformation.The primary factors contributing to stuck drills in deformed wells include smaller mill shoe sizes and larger cuttings sizes.Short well-washing cycles and targeted cuttings removal can effectively reduce sticking risks.If sticking occurs,high-tonnage pulling should be avoided.Instead,releasing the stick through up-anddown string motion,combined with high-volume nozzle spraying and annulus pumping,is recommended.The selection of coiled tubing should consider diameter,wall thickness,and steel grade to handle complex situations.Larger diameters,thicker walls,and low-frequency,multi-head hydraulic oscillators are more effective for unlocking horizontal sections.This approach can reduce the risk of drill sticking and solve the problem of horizontal section lock-ups,offering a reliable solution for smooth drilling and efficient production in wells with severe casing deformation.展开更多
Horizontal fracture-simulated completions remain the most reliable method of producing hydrocarbons from shale formations. The vast majority of unconventional wells are completed using the “Plug and Perf” method. Th...Horizontal fracture-simulated completions remain the most reliable method of producing hydrocarbons from shale formations. The vast majority of unconventional wells are completed using the “Plug and Perf” method. This method involves using either a coiled tubing (CT) with a positive displacement motor or a jointed pipe to mill out composite plugs after fracturing operations are completed. An estimated average of 120,000 composite plugs is installed in the US alone each year. Bridge plug drillouts from milling operations tend to accumulate in horizontal wells and can cause stuck pipe incidents and loss of well control. Efficient removal of composite plugs’ debris is crucial in achieving operational efficacies and full production potential. This paper provides an overview of the various bridge plug drillouts cleaning practices adopted in horizontal wells. It discusses several case histories, showcasing how operators solved cleanout challenges. Developed mechanistic models to better understand hole cleaning are also reviewed. As more unconventional wells are being set at more extensive depths, an economical and optimized coiled tubing process becomes increasingly important. This paper focuses on delivering a more conclusive set of recommendations to increase efficiency and improve current composite plug coiled tubing cleaning-milling practices, increase operational efficiency and reduce cost.展开更多
Shale gas resource in China is greatly different from that in the North America in term of natural endowment,so North America's experience and practice of shale gas revolution shall not be copied blindly in China....Shale gas resource in China is greatly different from that in the North America in term of natural endowment,so North America's experience and practice of shale gas revolution shall not be copied blindly in China.In order to realize scale effective development of shale gas resource in China,we analyzed and summarized the status quo of domestic shale gas stimulation technologies referring to the advanced concepts of shale gas development in the North America,considering the actual situations of shale gas resource in China.Then,some suggestions were proposed on the development direction of key shale gas fracturing technologies and the enhancement of engineering management.First,a data volume that integrates geological,engineering and production information is the base for designing and optimizing all segments of shale gas exploration,development and production.Therefore,it is necessary to break the“data isolated island”,strengthen data mining and improve the data application efficiency,so as to promote the integration of geo-engineering data fusion.Second,the geomechanics test&evaluation method and technology suitable for shale reservoirs shall be developed and improved by taking into consideration the anisotropic mechanical behaviors and ground stress characteristics of shale reservoirs,so as to increase the design level of geo-engineering integration program.Third,it is necessary to develop the dissolvable bridge plug,improve operation the efficiency of staged fracturing and reduce the operation risk,so as to achieve cost reduction and benefit increase of shale gas development.Fourth,there is still great room for the improvement of the engineering management system,which is worth exploring and studying further.Therefore,oil&gas industry and companies shall seize this critical strategic opportunity to actively optimize the current engineering management pattern and seek the optimal approach to quality improving and benefit increasing.In conclusion,the exploration and development of shale gas in China is currently in the early stage and there is an obvious gap compared with foreign countries in terms of technology&equipment,production management,exploration and development achievement and policy®ulation.Therefore,it is in an urgent need to innovatively explore a way feasible for the actual shale gas development in China based on the resource conditions of its own after referring,digesting and absorbing the hydraulic fracturing experience and management concept of shale gas revolution in the United States.展开更多
The application of horizontal well drilling and large-scale sand fracturing can secure an increased production in shale gas reservoirs despite of frequent gas wellbore blockage.It is vital to remove the residual bridg...The application of horizontal well drilling and large-scale sand fracturing can secure an increased production in shale gas reservoirs despite of frequent gas wellbore blockage.It is vital to remove the residual bridge plug debris and sand in wellbore cleaning operation and to ensure an unblocked downhole production channel of shale gas well for a safe and smooth production process.In this paper,the current situations of the wellbore cleaning technology for horizontal wells were analyzed,and the technical challenges in wellbore cleaning treatment of shale gas horizontal wells were summarized.Based on global development of wellbore cleaning technologies for horizontal wells,technical researches were carried out on cleaning tools&technologies and working fluid performance,and cleaning treatment tools were studied and developed.Besides,technical measures of cleaning treatment were put forward and their field application effects were analyzed.Results reveal that the milling-fishing integrated tool,developed to treat large bore bridge plug,is capable of washing-over and fishing out large bore bridge plug in one trip after running in the hole;for long horizontal sections where reverse cyclone sand-washing tool is applied,the tool can prevent sand from settling so as to flush sand out of the wellbore;for normal-pressure and high-pressure wells,gas well backflow fluid,KCl and CaCl_(2) solution may serve as working fluid,while for low pressure wells,foam fluid can be used;for low-pressure wells,the negative pressure fishing tool is designed and optimized to drive debris or sediment into the tool through forming local negative pressure adsorption,thus complete the fishing operation.In conclusion,the new wellbore cleaning technology,which suits shale-gas horizontal wells,has laid the groundwork for large-scale wellbore cleaning treatment of shale gas wells.展开更多
Coiled tubing drilling and grinding technology is widely used in shale gas well exploitation projects in Sichuan-Chongqing area. In recent years, the exploration and development of unconventional oil and gas resources...Coiled tubing drilling and grinding technology is widely used in shale gas well exploitation projects in Sichuan-Chongqing area. In recent years, the exploration and development of unconventional oil and gas resources such as shale gas and shale oil have developed rapidly in China, and shale gas in Sichuan-Chongqing block has gradually developed in the direction of deep layer, normal pressure and encryption adjustment in old areas. Affected by casing deformation, high temperature in the well, high pressure in the well, tool performance, operating parameters and other factors, the coiled tubing is prone to sticking due to the unreturned debris, and the complicated horizontal section of the well trajectory leads to the tubing self-locking not reaching the target position, and the friction resistance between tubing and casing leads to serious tool wear or fracture, which has a serious impact on the subsequent exploitation of shale gas wells. In this paper, various risks in drilling and grinding bridge plug technology during fracturing are analyzed, and according to the actual situation on the spot, some methods are put forward, such as shoe grinding selection scheme, tool selection optimization and auxiliary material use, drilling and grinding technical parameters optimization, etc., in order to avoid complicated situations and achieve the purpose of improving quality and increasing efficiency.展开更多
基金supported by Major Technology Promotion Project of CNPC,China(No.2022ZT01)Major Field Test Project of CNPC,China(No.2019F-31-04)CNPC Chuanqing Drilling Engineering Company Science and Technology Special Project,China(No.CQ2024B-11-Z2-4).
文摘Milling bridge plugs in shale gas wells with severe casing deformation often leads to the accumulation of cuttings,increasing the risk of stuck drill bits.Friction in the wellbore further complicates tool deployment into the horizontal section,posing challenges to efficient plug drilling and achieving wellbore access to the target layer.This paper integrates the theory of positive displacement motors and models their actual working characteristics to study the milling of bridge plugs in severely deformed horizontal wells.It examines the effects of coiled tubing diameter and wall thickness on the bending load of horizontal sections and discusses key technical requirements,including the timing of plug drilling,extending the run in the horizontal section,parameter control,and real-time field analysis.Field practices have shown that after casing deformation occurs,priority should be given to drilling out the bridge plugs below the point of deformation.The primary factors contributing to stuck drills in deformed wells include smaller mill shoe sizes and larger cuttings sizes.Short well-washing cycles and targeted cuttings removal can effectively reduce sticking risks.If sticking occurs,high-tonnage pulling should be avoided.Instead,releasing the stick through up-anddown string motion,combined with high-volume nozzle spraying and annulus pumping,is recommended.The selection of coiled tubing should consider diameter,wall thickness,and steel grade to handle complex situations.Larger diameters,thicker walls,and low-frequency,multi-head hydraulic oscillators are more effective for unlocking horizontal sections.This approach can reduce the risk of drill sticking and solve the problem of horizontal section lock-ups,offering a reliable solution for smooth drilling and efficient production in wells with severe casing deformation.
文摘Horizontal fracture-simulated completions remain the most reliable method of producing hydrocarbons from shale formations. The vast majority of unconventional wells are completed using the “Plug and Perf” method. This method involves using either a coiled tubing (CT) with a positive displacement motor or a jointed pipe to mill out composite plugs after fracturing operations are completed. An estimated average of 120,000 composite plugs is installed in the US alone each year. Bridge plug drillouts from milling operations tend to accumulate in horizontal wells and can cause stuck pipe incidents and loss of well control. Efficient removal of composite plugs’ debris is crucial in achieving operational efficacies and full production potential. This paper provides an overview of the various bridge plug drillouts cleaning practices adopted in horizontal wells. It discusses several case histories, showcasing how operators solved cleanout challenges. Developed mechanistic models to better understand hole cleaning are also reviewed. As more unconventional wells are being set at more extensive depths, an economical and optimized coiled tubing process becomes increasingly important. This paper focuses on delivering a more conclusive set of recommendations to increase efficiency and improve current composite plug coiled tubing cleaning-milling practices, increase operational efficiency and reduce cost.
基金supported by the National Key Research and Development Project“Water-Energy Nexus and Key Technologies on Efficient and Green Utilization of Water and Energy Resources”(No.2018YFE0196000).
文摘Shale gas resource in China is greatly different from that in the North America in term of natural endowment,so North America's experience and practice of shale gas revolution shall not be copied blindly in China.In order to realize scale effective development of shale gas resource in China,we analyzed and summarized the status quo of domestic shale gas stimulation technologies referring to the advanced concepts of shale gas development in the North America,considering the actual situations of shale gas resource in China.Then,some suggestions were proposed on the development direction of key shale gas fracturing technologies and the enhancement of engineering management.First,a data volume that integrates geological,engineering and production information is the base for designing and optimizing all segments of shale gas exploration,development and production.Therefore,it is necessary to break the“data isolated island”,strengthen data mining and improve the data application efficiency,so as to promote the integration of geo-engineering data fusion.Second,the geomechanics test&evaluation method and technology suitable for shale reservoirs shall be developed and improved by taking into consideration the anisotropic mechanical behaviors and ground stress characteristics of shale reservoirs,so as to increase the design level of geo-engineering integration program.Third,it is necessary to develop the dissolvable bridge plug,improve operation the efficiency of staged fracturing and reduce the operation risk,so as to achieve cost reduction and benefit increase of shale gas development.Fourth,there is still great room for the improvement of the engineering management system,which is worth exploring and studying further.Therefore,oil&gas industry and companies shall seize this critical strategic opportunity to actively optimize the current engineering management pattern and seek the optimal approach to quality improving and benefit increasing.In conclusion,the exploration and development of shale gas in China is currently in the early stage and there is an obvious gap compared with foreign countries in terms of technology&equipment,production management,exploration and development achievement and policy®ulation.Therefore,it is in an urgent need to innovatively explore a way feasible for the actual shale gas development in China based on the resource conditions of its own after referring,digesting and absorbing the hydraulic fracturing experience and management concept of shale gas revolution in the United States.
基金Project supported by the Research Project of PetroChina Southwest Oil and Gas Field“Study on wellbore cleaning technologies for shale-gas horizontal wells”(No.:20180302-11).
文摘The application of horizontal well drilling and large-scale sand fracturing can secure an increased production in shale gas reservoirs despite of frequent gas wellbore blockage.It is vital to remove the residual bridge plug debris and sand in wellbore cleaning operation and to ensure an unblocked downhole production channel of shale gas well for a safe and smooth production process.In this paper,the current situations of the wellbore cleaning technology for horizontal wells were analyzed,and the technical challenges in wellbore cleaning treatment of shale gas horizontal wells were summarized.Based on global development of wellbore cleaning technologies for horizontal wells,technical researches were carried out on cleaning tools&technologies and working fluid performance,and cleaning treatment tools were studied and developed.Besides,technical measures of cleaning treatment were put forward and their field application effects were analyzed.Results reveal that the milling-fishing integrated tool,developed to treat large bore bridge plug,is capable of washing-over and fishing out large bore bridge plug in one trip after running in the hole;for long horizontal sections where reverse cyclone sand-washing tool is applied,the tool can prevent sand from settling so as to flush sand out of the wellbore;for normal-pressure and high-pressure wells,gas well backflow fluid,KCl and CaCl_(2) solution may serve as working fluid,while for low pressure wells,foam fluid can be used;for low-pressure wells,the negative pressure fishing tool is designed and optimized to drive debris or sediment into the tool through forming local negative pressure adsorption,thus complete the fishing operation.In conclusion,the new wellbore cleaning technology,which suits shale-gas horizontal wells,has laid the groundwork for large-scale wellbore cleaning treatment of shale gas wells.
文摘Coiled tubing drilling and grinding technology is widely used in shale gas well exploitation projects in Sichuan-Chongqing area. In recent years, the exploration and development of unconventional oil and gas resources such as shale gas and shale oil have developed rapidly in China, and shale gas in Sichuan-Chongqing block has gradually developed in the direction of deep layer, normal pressure and encryption adjustment in old areas. Affected by casing deformation, high temperature in the well, high pressure in the well, tool performance, operating parameters and other factors, the coiled tubing is prone to sticking due to the unreturned debris, and the complicated horizontal section of the well trajectory leads to the tubing self-locking not reaching the target position, and the friction resistance between tubing and casing leads to serious tool wear or fracture, which has a serious impact on the subsequent exploitation of shale gas wells. In this paper, various risks in drilling and grinding bridge plug technology during fracturing are analyzed, and according to the actual situation on the spot, some methods are put forward, such as shoe grinding selection scheme, tool selection optimization and auxiliary material use, drilling and grinding technical parameters optimization, etc., in order to avoid complicated situations and achieve the purpose of improving quality and increasing efficiency.
