漏失地层圈闭压力的形成与处置技术

Research on Formation and Disposal for the Trap Pressure in Leakage Formation

有圈闭或有限圈闭的漏失地层,在进行井漏治理、精细控压作业以及因工艺需要向地层推入钻井液时,大量外部流体进入漏失地层,当漏失量小于外部流体进入量时会形成圈闭压力或短期圈闭压力。现场实践表明形成的圈闭压力依靠地层漏斗压降通过漏失通道延展、地层再漏失释放的时间可能会比较长,且部分井形成的圈闭压力可能会比较高,有的井虽然压力不高但圈闭能量大,释放地层圈闭压力的,回流量也会比较大,如果判断失误、处置不当可能引发井控问题。文章针对外部流体进入漏失地层形成的圈闭压力处置的技术问题,开展了对进入井筒的地层流体性质、地层回流的原因、处置技术进行了研究,较好地解决了漏失地层形成的短期圈闭压力,研究成果在HS-2、JT-1等井进行了应用,取得了较好的现场应用效果。

In the leakage formation with trap or limited trap,a large amount of external fluid will enter the lost formation during lost circulation treatment,managed pressure operation and pumping drilling fluid into formation as process required,resulting in trap pressure or short-term trap pressure,especially when a large amount of external fluid enters the lost formation.Field practice shows that the formed trap pressure may take a long time to extend through the leakage channel and then loss into formation and release again.In field practice,it is believed that some wells may have high trap pressure,and some wells may have low pressure but with high trap energy,which can release formation trap pressure and return flow in a controlled manner.Misjudgment and improper disposal will lead to well control problems.In view of the technical problem of trap pressure disposal caused by external fluid entering the lost formation,this paper carried out a research on the fluid property,the cause of backflow and disposal method of formation fluid entering the wellbore,solving the technical problem of short-term trap pressure disposal caused by formation loss.It has been used in Well HS-2,Well Jt-1 and other wells with better field application results.