渤中19-6构造潜山花岗片麻岩地层漏失压力分析

Analysis on leakage pressure of buried-hill granite gneiss in BZ19-6 structure

韩耀图 马英文 谢涛 岳明 王文

HAN Yaotu MA Yingwen XIE Tao YUE Ming WANG Wen

中海石油(中国)有限公司天津分公司

Tianjin Branch of China National Offshore Oil Co., Ltd., Tianjin 300459, China

渤中19-6构造潜山地层钻井过程中发生不同程度的井漏，合理漏失压力的确定是防漏堵漏的关键。在分析裂缝性地层漏失机理的基础上，从统计学的角度出发，提出漏失压差与漏失速率的相关性关系，建立了潜山裂缝性地层漏失压力模型，并以渤中19-6构造实际漏失点进行验证。结果表明：渤中19-6构造井漏深度分布在4 200~5 300 m，漏失地层岩性均为花岗片麻岩，潜山地层漏失以微小-小裂缝性漏失为主；漏失压差与漏失速度存在幂函数关系；测算出渤中19-6构造实际漏失点的井底压力高于漏失压力，符合工程实际。研究认为，提出的裂缝性地层漏失模型能够为今后的钻井液密度设计提供指导。

Circulation loss of different degrees occurs during the drilling of the buried hill strata in BZ19-6 structure.The key to prevent and plug lost circulation is to confirm the leakage pressure reasonably.In this paper, the leakage mechanisms of fractured formations were analyzed.Then, from the viewpoint of statistics, the correlation between the leakage pressure difference and the leakage rate was put forward.Finally, a leakage pressure model for fractured formations of buried hills was established and verified based on the actual leakage point of BZ19-6 structure.It is shown that the depth of leakage points in BZ19-6 structure is mostly in the range of 4 200-5 300 m, and the lithology where the leakage occurs is granitic gneiss.The leakage in buried-hill formations is mainly micro-minor fractured leakage.It is the power function relationship between the leakage pressure difference and the leakage rate.The calculated bottom hole pressure is higher than the leakage pressure at the actual leakage points of BZ19-6 structure, which conforms to the engineering practice.In conclusion, the fractured leakage model established in this paper can provide the guidance for the future design of drilling fluid density.

10.13639/j.odpt.2018.S0.038