摘要
为了解决现有控压钻井工艺复杂和设备配套多的问题,并实现平衡压力钻井,从井内压力平衡的监控与认定方法入手,分析了井内压力平衡关系和控压钻井现状,研究了"液量稳定"控压原理、工艺与实现方法,形成了"恒液面"自动控制技术,实现了"液量稳定"控压钻进时的自动控制,钻井现场液面控制精度小于25 mm;钻井过程中可以根据循环罐液面变化调节节流阀,以保持"液量稳定",实现井底压力与地层压力的实时平衡,进行平衡压力钻井.现场应用时,利用35 MPa旋转防喷器,以井口压力不大于7 MPa为原则,采用人工手动节流控制方法顺利钻穿了压力系数大于2.0、"零"压力窗口的盐水层和压力系数大于1.8、"零"压力窗口的灰岩裂缝性气层,解决了土库曼斯坦阿姆河右岸B区块的钻井难题.研究结果表明,与其他控压方式相比,"液量稳定"控压钻井技术的配套设备简化,控压工艺简单,具有较好的现场实用性.
Abstract
In order to solve the problems of complex pressure control drilling technologies and excessive equipment matching and achieve balanced pressure drilling,the monitoring and identification methods of pressure balance in the well were first studied.The in-well pressure balance relationship and the state of pressure control drilling were analyzed.The pressure control principles,processes,and implementation method of"stable fluid volume"were studied,forming the"constant fluid level"automatic control technology to enable automatic control in"stable fluid volume"pressure control drilling.The fluid level control accuracy on the drilling site was maintained within 25 mm.The throttle valve could be adjusted to ensure"stable fluid volume"according to the changes in the circulating tank fluid level during drilling.This facilitated real-time balance between bottomhole pressure and formation pressure and ensured balanced pressure drilling.In on-site applications,a 35 MPa rotary blowout preventer was utilized,with a wellhead pressure not exceeding 7 MPa,and manual throttling control was adopted to successfully drill through the saltwater layer with a pressure coefficient of greater than 2.0 and zero pressure window,as well as the limestone fractured gas layer with a pressure coefficient of greater than 1.8 and zero pressure window,solving the drilling problem in Block B on the right bank of the Amu Darya River in Turkmenistan.Research has shown that compared with other pressure control methods,the supporting equipment of"stable fluid volume"pressure control drilling technology is simplified;the pressure control process is simple,and it has good on-site application value.
NETL
NSTL
万方数据