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
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.
