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美国墨西哥湾 (GOM )的深海钻井通常以极小的孔隙压力和破裂压力梯度窗口而著称。在美国墨西哥湾地区深水钻井中 ,需要对当量循环密度 (ECD)进行严格控制 ,使之不超过地层的破裂压力梯度 ,进而减少井漏并使停工时间最小化。深水钻井通常使用合成基钻井液 (SBM )。在接单根时井底钻具的周围常常会发生大块岩屑沉淀现象 ,对此 ,现场操作人员和钻井液供应商提出了几项技术措施以提高井眼清洗效率和优化钻井操作。经过对各种情况下井眼清洗效率的研究 ,可以准确地预测当量循环密度及确定给定机械钻速下的安全操作窗口。这个结果随后在美国墨西哥湾地区两口深海井中应用 ,井深分别为 2 80 0ft和 880 0ft,采用的是合成基钻井液体系。文中提供了水力研究和现场试验的结果 ,并给出了今后钻深海井的一些推荐做法
Deep-sea drilling in the Gulf of Mexico (GOM) is commonly known as a window of minimal pore pressure and fracture pressure gradients. In deepwater drilling in the Gulf Coast of the United States, the ECD needs to be tightly controlled so as not to exceed the fracture pressure gradient of the formation, thereby reducing well losses and minimizing downtime. Deep-water drilling usually uses synthetic base drilling fluid (SBM). Large scale cuttings often occur around bottom hole tools when receiving a single root. In response, on-site operators and drilling fluid suppliers have proposed several technical measures to improve borehole cleaning efficiency and optimize drilling operations. After studying the wellbore cleaning efficiency in various situations, it is possible to accurately predict the equivalent circulating density and determine the safe operating window for a given ROP. This result was subsequently applied to two deep-sea wells in the Gulf of Mexico, with depths of 280 ft and 880 ft, respectively, using a synthetic-based drilling fluid system. The paper provides the results of hydraulic studies and field tests and gives some recommended practices for drilling deep sea wells in the future