Improved Drilling Technology Application And Research In West Sichuan Block

The main target stratum of west Sichuan gas field is Penglai zhen formation and Shaxi miao formation.Most wells are horizontal and some exploration wells are slant.In this block the formation is abrasive and nonuniformity is hard,drillability is weak.There are some problems such as low rate of penetration(ROP)in build-up sections,high pump pressure so the flow rate is limited in some areas,less information regarding to application of improved drilling tools,adjustment of properties of high density drilling fluid in some areas etc.It is essential to overcome these issues to improve ROP and decrease drilling cost drastically.Combined with geologic entity and formation characteristics of west Sichuan block,this thesis did a study to improve ROP in build up section,optimized drilling bits for this block through the agency of test of rock behavior and analysis of logging data.Combination of directional PDC flow numerical simulation analysis,this paper employed 8-1/2 ?WHMGP461-5 five blades bit,whose main cutting teeth are 19 mm laminate sheet,helix angle of blade is 15 degree,and trench teeth.This kind of bit's corona contour is shallow inner cone-short inner cone structure.The average ROP of this bit is 6.83 m/h on well site,which reached expected impact.To achieve the macroscopic control of trajectory,this paper studied trajectory & processing and landing control technology.It present eight technical procedures related to tool select and well site operations.Simultaneously,to guarantee the drilling of directional and horizontal sections smoothly,this paper brought up some technical strategies for wellbore.Hydraulic thruster can solve that can not put weight on bits while drilling due to the large angle.This paper presented service conditions and BHA of hydraulic thruster through the analysis of several wells in Shifang block.Regarding to the contradiction of high density drilling fluid between rheological property and settleability in Zhongjiang,Xinchang blocks.This paper studied the effect of temperature and bentonitic clay content to the properties of water based mud,and performed plentiful experimental research.Consequently,the system and formulations were summarized,which performed well in Zhongjiang,Xinchang blocks.