全过程欠平衡钻井储层保护机制

The Reservoir Protection Mechanism of Underbalanced Drilling Operation

系统总结了国内外全过程欠平衡钻井的研究现状;分析了常规欠平衡钻井过程中,因起下钻、测井、完井等存在的压井作业,使井底储层处于间断过平衡状态,在固相侵入、水相圈闭和水敏等作用下,造成严重的储层损害;论述了全过程欠平衡钻井技术,从钻开储层到交井投产的全过程欠平衡保护储层的机制,并以邛西3井、4井为例说明了全过程欠平衡钻井在储层保护、减少井漏等井下复杂事故、提高产量,以及快速、真实、准确地发现储层、评价储层方面的优势。

The current research status on the underbalanced drilling operation at home and abroad is systematically summered. The reservoir damage mechanism and during the normal process of underbalanced drilling operation, the reason making well bottom reservoir run into intermittent overbalanced drilling operation status caused by drilling operations, such as tripping, logging, and well completion, are analyzed. Intermittent overbalanced drilling operation causes the seriously reservoir damage due to the intrusion of the solid phase, water trapping, and water sensitivity. The technology and the reservoir protection mechanism of underbalanced drilling operation from open reservoir to reservoir production are discussed. Finally, the advantages of underbalanced drilling operation, involving reservoir protection, the reduction of lost circulation and other drilling accident, production increase, quick, real, and exact discovery of reservoir, and evaluation of reservoir, are illustrated by taking wells Qx3 and QX4 as the example.