诱导性裂缝防漏堵漏钻井液研究

Study of Lost Circulation Protection and Control Drilling Fluid for Induced Cracks

赵 巍 李 波 高云文 黄占盈

ZHAO Wei LI Bo GAO Yuan-wen HUANG Zhan-YING

由于诱导性裂缝产生，华庆油田在钻井中发生了严重漏失。目前桥塞堵漏剂对孔隙、裂缝尺寸的适应性较差。本文通过对架桥材料，聚合物吸附材料和填充材料优选及颗粒级配，确定了架桥材料为不同粒径橡胶粒（粒径为0.6~1.0 mm、1.1~1.5 mm和1.6~2.0 mm的分别占30％、30％和40％），聚合物吸附材料为CDL-1；填充材料由30％蛭石（粒径0.4~0.5 mm）、5%~10%云母、5%~10%锯末、20%~25%桥塞堵漏剂QD-1、20%~30%桥塞堵漏剂QD-2和10%~20%单向压力封堵剂DF-A组成。通过正交实验确定在基浆（清水＋0.3％PAM+4%膨润土）中加入2%橡胶颗粒、0.2% CDL-1和3%填充材料，得到适应性防漏堵漏钻井液。该钻井液的粘度10 mPa·s，动切力3 Pa,承压能力达到4 MPa，最小封堵时间10 min。现场试验证明防漏堵漏钻井液可在较短时间内有效封堵漏层，取得了良好的应用效果。

Serious mud losses happened at Huaqing oilfield due to the induced fractures. The current bridging plug agent is poor adaptable to the fracture and pore size. the bridging material, polymeric adsorbent materials and filler material and particle size distribution were optimized, as a result, the bridging materials were compounded of the rubber particles with different particle size, which the percentage of particle diameter of 0.6—1.0 mm, 1.1—1.5 mm and 1.6—2.0 mm was 30%, 30% and 40%, respectively. The polymer adsorption materials was CDL-1. the filling material consisted of 30% vermiculite with particle diameter of 0.4—0.5 mm, 5%—10% of mica, 5%—10% of sawdust, 20%—25% of the bridge plug agent QD-1, 20%—30% of QD-2 and 10%—20% of the one-way pressure sealer DF-A. By orthogonal experiments, the plugging drilling fluid adaptable to leakproof was determined by adding 2% rubber particles, 0.2% CDL-1 and 3% fill material in the base slurry (water+0.3% PAM +4% bentonite). The viscosity of the drilling fluid was of 10 mPa ? s, the yield point was of 3 Pa, the pressure capacity was of 4 MPa and the minimum closure time was of 10 min. The field test proved the drilling fluid could seal the lost layer in a relatively short time effectively.