中东Lower Fars厚盐膏层钻井液室内研究

Laboratory study on drilling fluid of thick salt bed in Lower Fars of Middle East

邢希金 赵欣 刘书杰 李玉光

XING Xijin ZHAO Xin LIU Shujie LI Yuguang

中海油研究总院，北京　100027 中国石油大学华东，山东青岛　266580

Research Institute of CNOOC, Beijing 100027, China China University of Petroleum, East China, Qingdao 266580, China

已钻井揭示出中东Lower Fars盐膏层钻井液流变性差，存在漏失及溢流等问题。研制了密度为2.30 g/cm3的复合盐饱和盐水钻井液，其塑性黏度为53 mPa·s，动切力为15 Pa；API滤失量小于2 mL，120 ℃/3.5 MPa下的高温高压滤失量8 mL，滤饼厚度1 mm；盐膏样品和泥岩样品回收率分别为88%、79%；10% NaCl、1% CaCl2和8%劣质土污染后流变性变化小，滤失量小于3.5 mL，润滑系数小于0.1，缝宽200μm、5 MPa下累积漏失量2.4 mL/3 min。不仅能够满足中东Lower Fars盐膏层安全钻进需求，而且为国外类似油田钻进盐膏层提供了经验。

Drilled wells reveal that the drilling fluid for Lower Fars salt-gypsum bed in Middle East has such problems as poor rheological property, lost circulation and overflow, etc. A composite saturated brine fluid with a density of 2.30 g/cm3 was developed, whose PV is 53 mPa·s, YP is 15 Pa and API filtration loss is less than 2 mL; its HTHP filtration loss is 8 mL under 120 ℃/3.5 MPa; its filter cake thickness is 1 mm; the recovery rates of salt-gypsum sample and mudstone sample are 88% and 79% respectively. When contaminated by 10% NaCl, 1% CaCl2 and 8% bad soil, its rheological property changed little, with filtration was less than 3.5 mL, lubricity was less than 0.1, fracture width was 200 μm , and the cumulative loss under 5 MPa was 2.4 mL/3 min. It can not only meet the drilling of Lower Fars salt-gypsum bed in the Middle East, but also provide experiences for drilling of salt-gypsum bed in similar oilfield in other countries.

10.13639/j.odpt.2014.04.015