Research On Directional Drilling Technology Of Zh-L11 Coalbed Methane Well In Jincheng

As the supply and demand of new energy continues to rise,the Coalbed Methane(CBM)industry attached to unconventional natural gas has attracted much attention.At the same time.CBM industry has occupied a decisive position in the future of the current new energy industry.Shanxi Province is rich in CBM resources and has a large number of surface CBM L-type Wells.However,there are common directional drilling technical problems such as low drilling efficiency,high and frequent drilling accidents.In this paper,ZH-L11 is selected as the research object among many L-shaped surface CBM Wells in Shanxi Province.The common problems of this type of drilling are studied.Through the theoretical analysis of a large number of data and the use of ANSYS-FLUENT finite element simulation software for drilling numerical simulation analysis.On the basis of field verification,the problems related to directional drilling technology of this type of drilling are studied in depth and some conclusions are drawn as follows.(1)During the drilling process of the Well ZH-L11,it is divided into three stages:startup,rigid rebound and stabilization.The stress surges that occurred during this period resulted in at least three violent drill pipe shocks.This is one of the main reasons for the rapid loss of drill pipe.(2)There are some drilling fluid flow laws in the directional drilling inclined section of the Well ZH-L11.The flow rate of drilling fluid in annulus clearance presents a flat jujube shape with sharp ends and thick middle.In addition,there are elliptic disturbance areas arranged side by side,and the general edge of the region is wavy.Reducing the area and time in the zone can improve directional drilling efficiency.(3)When the drilling fluid flow rate in the Well ZH-L11 studdenly increases,the surrounding rock will deform significantly.The initial stage is the stage where the wall rock is most vulnerable to failure and the stability of the shaft wall is the worst.The range of critical failure area of wellbore surrounding rock can be roughly summarized as the fan-shaped area where the included Angle between drilling section and gravity direction ranges from 21.5 degrees to 43.6 degrees.(4)Compared with other wells of the same type,the drilling results of the field test showed the following conclusions.The use of azimuth gamma measurement while drilling technology and small pilot hole branch hole technology makes drilling trajectory control more accurate.Improved drilling fluid configuration by section can make it more powerful and more targeted.The drilling efficiency of the Well ZH-L11 increased by 16.13 percent.At the same time,the drilling rate in the target area increased to 95.13 percent,and the wellbore instability rate was only 5.40 percent.The research and application of comprehensive directional drilling technology in ZH-L11 well has achieved remarkable results.