可回收式套管堵塞阀换装四通技术

Technique for Replacing Spool Using Retrievable Casing Plugging Valve

试油、投产作业期间,因工艺需要常进行钻井四通与采油四通换装施工,施工过程中井口有一段时间处于无控状态,井控安全隐患极大。常规采用桥塞暂时封堵井筒或多功能试油管柱换装四通工艺,可保证施工本质安全,但存在多功能管柱结构复杂、作业周期长、钻磨桥塞损伤套管、可取式桥塞工具出现复杂后处理难度大等问题,不利于油气井安全高效开发。针对以上问题,塔里木油田工程技术人员创新研制了可回收式套管堵塞阀,用于试油和修井期间换装四通时封堵套管。工具主要由密封机构、坐封解封机构、锚定机构、送入回收机构等组成,工作压力52MPa,回收前可进行压力检测,建立压井通道进行压井作业。现场应用后取得良好效果,换装四通后作业时间由应用前的176h降至11h,一次成功率达100%,提高了井筒完整性,降低了作业成本。

In the process of well testing and oil production,drilling spools need to be replaced with production spools as per technical requirements.In the operations,the wellhead is out of control for a period of time,so that there is a great potential safety hazard for well control.The conventional method to handle the problem is to temporarily seal off the wellhead with a bridge plug or to replace the spool with a multi-function testing tubing string.The measure can ensure the essential safety of operations,but the multifunctional tubing string has some disadvantages,such as complicated structure,longer operation period,casing damage caused by drilling and milling the bridge plug,troubles of retrievable bridge-plug tools which are difficult to deal with and so on.All of these problems are unfavorable to oil and gas well safe and efficient development.To eliminate the above problems,engineering technical personnel of Tarim Oilfield developed retrievable casing plugging valves used to plug casing when replacing spool in well testing and workover operations.With an operational pressure of52MPa,the tool is mainly composed of a sealing unit,a setting and releasing unit,anchoring unit and running and retrieving unit,etc.The pressure test can be conducted before the tools being retrieved,and established a passage for well killing.A good result has been obtained on field application,such as the time for replacing the spools was decreased from 176h to 11h,and the one-time success rate reached100%,which improved the wellbore integrity and reduced the operation costs.