Research On ECD Check And Control Technology Of High Temperature And High Pressure Wells

With the increasing difficulty of oil exploration and development,the narrow density window problem appearing when drilling HPHT wells is now affecting the security of drilling.It has brought a series of problems to the drilling process.When drilling the HPHT well,ECD's forecast is the key to safe drilling.Controlling the wellbore pressure is also important to speed and safety.When drilling the HPHT wells,the density of drilling fluid is affected by downhole temperature and pressure.The density of drilling fluid is no more a constant.,it will change with pressure and temperature,an then it will influence the equivalent circulating density.This article is based on the drilling fluid rheological experiments under HTHP circumstance,and it has studied the rules of rheological parameters changing with the temperature and pressure.Based on the PWD data collected from the well of Keshen area,this article has checked the ECD calculating model,it also studied the influence of the cycle time,displacement and other factors on ECD,and it gives advice to guide how to control the downhole pressure under different conditions.Research of checking the ECD model and study the wellbore pressure controlling technology is significant for security in HPHT well drilling,which also brings the result of cutting down drilling costs,reducing blowouts,lost circulation and other complications situations.