气举技术应用于深海无隔水管泥浆回收钻井工艺可行性分析

Feasibility analysis of gas lift technology for application in deep-sea riserless mud recovery drilling

无隔水管泥浆回收钻井技术作为新兴钻井技术,具有安全环保、简化井身结构和降低钻探风险等优点。传统的无隔水管泥浆回收钻井技术依靠水下泵将海底井口泥浆举升至甲板面,该方式对水下泵的举升能力及可靠性要求极高。未来深海钻井领域,水下泵将会是限制无隔水管泥浆回收钻井技术应用的“瓶颈”。本文借鉴陆地气举反循环钻井原理,利用气举技术部分或完全替代水下泵,分别从设备技术现状、流量可调性、适用环境、井控安全等方面探究气举用于无隔水管泥浆回收技术的可行性。结果表明,气举反循环技术及相关设备性能满足无隔水管泥浆回收的使用要求,而且具有上返流量可调、安全等特点,有较高的研究应用价值。

As an emerging drilling technology,riserless mud recovery drilling technology has the advantages of safety and environmental protection,simplified well structure and reduced drilling risk. The traditional riserless mud recovery drilling technology relies on subsea pumps to lift drilling mud from the subsea wellhead to the deck surface,which requires extremely high lifting capacity and reliability of the subsea pumps. Therefore,for future deep-sea drilling,subsea pumps will be the bottleneck restricting the application of riserless mud recovery drilling technology. Drawing on the principle of onshore gas lift reverse circulation drilling,this paper explores the feasibility of use of gas lift technology in part or in whole to replace subsea pumps for mud recovery in terms of equipment availability,flow adjustability,applicable conditions,well control safety,etc. The results show that the performance of gas lift reverse circulation technology and related equipment can meet the requirements of RMR with the features of adjustable up-hole return flow and safety,and it is highly worthy of research.