渤海油田中深部地层井壁稳定对策

Countermeasures for the borehole stability in middle and deep strata of Bohai Oilfield

胡成军 陈强 张鹏 宋晓伟 雷志永 刘晓东

HU Chengjun CHEN Qiang ZHANG Peng SONG Xiaowei LEI Zhiyong LIU Xiaodong

中海油服油田化学事业部

Oilfield Chemistry Department, China Oilfield Services Limited, Tianjin 300459, China

深部地层是渤海油田重要的储量增长点。深部地层是以伊利石、伊蒙混层等非膨胀性黏土矿物为主的泥页岩，水化膨胀、分散能力差，水化膜短程斥力极易导致水化界面变形，易造成井壁坍塌失稳。基于地层微纳米裂缝失稳机理，针对渤海油田深部地层井壁失稳特征，提出“物化封堵+加强抑制+活度平衡+合理密度支撑”的“多元协同”钻井液稳定井壁防塌对策，并进行了实际应用，解决了渤中、蓬莱7-6等区块东营组及沙河街组中深部地层泥页岩井壁失稳问题。

Deep strata play an important role for the reserve growth of Bohai Oilfield.The mud shale in deep strata which is mainly composed of non-expansion clay minerals (e.g.illite and illite/smectite mixed layer) is poor in hydrate expansion and dispersion capacity, and the short-range repulsion of hydration film can lead to the deformation of hydration interface.Thus, borehole collapse and instability tends to happen easily.In this paper, according to the micro- and nano-scale instability mechanisms, the "multi-element collaboration"countermeasures for drilling fluid stability and borehole collapse prevention were put forward to deal with the peculiar borehole instability forms in the deep strata of Bohai Oilfield.The countermeasures include physicochemical plugging, inhibition enhancement, activity equilibrium and rational density support.Then, they were applied practically.And thanks to their application, the borehole instability in the middle and deep mud shale of Dongying Formation and Shahejie Formation in Bozhong Block and Penglai 7-6 Block is solved.

10.13639/j.odpt.2018.S0.026