钻井液与完井液2023，Vol.40Issue(5)：602-610,9.DOI:10.12358/j.issn.1001-5620.2023.05.008
适用于页岩油钻井的低伤害防塌水基钻井液体系
Low Damage Highly Inhibitive Water Based Drilling Fluid for Drilling Shale Oil Reservoir
摘要
Abstract
Chang 73 reservoirs have the characteristics of micron-nano crack development and low strength of formation rocks.It can lead to the intrusion of drilling fluid filtrate into the reservoir causing borehole collapse and reservoir damage.We clarified the destabilization mechanism of Chang 73 shale and the technical difficulties of drilling fluids.Then the multi-stage particle size distribution intervals with broad spectrum was constructed by introducing rigid and deformable plugging materials,which was based on the"1/3 and 2/3 bridging rule".Next,using the instantaneous water loss as the evaluation index,the optimal ratio was optimized by surface response modeling,and the combination of anti-collapse inhibitor was preferred in the room.Based on which a low damage and anti-collapse water-based drilling fluid was developed.The results of the evaluation indicated that the drilling fluid can effectively balance the formation collapse stress,and the rheological properties remain satisfactory after aging for 72 h.It also reduced shale linear swell by 16.74%and 13.61%compared to clear water environments and in the field drilling fluids respectively.Due to its remarkable plugging properties,the instantaneous filtration loss of the drilling fluid was only 1mL and the plugging rate of the core was as high as 93.5%.Based on the reservoir protection capability of the drilling fluid,there was no pore throat plugging in the core slab after mud cake removal and the permeability recovery value of the core was as high as 95.2%.It was important that the lubricity of the drilling fluid was moderate and the friction coefficient remain around 0.08 before and after the drilling fluid ages.The average diameter expansion rate of the horizontal section in the field test was only 4.27%,and the average mechanical drilling speed could reach 18.4m/h.There were no complicated downhole accidents in the horizontal section during the drilling period,and all the performances could meet the needs of horizontal wells in the Chang 73 reservoirs.关键词
页岩油/水基防塌钻井液/封堵性/储层保护Key words
Shale oil reservoirs/Anti-collapse water based drilling fluid/Plugging/Reservoir protection分类
能源科技引用本文复制引用
艾磊,高云文,欧阳勇,辛庆庆,周宇..适用于页岩油钻井的低伤害防塌水基钻井液体系[J].钻井液与完井液,2023,40(5):602-610,9.基金项目
中国石油天然气股份有限公司科学研究与技术开发项目"中低熟页岩油原位转化基础理论硏究与关键技术开发及先导试验"(2021DJ5203). （2021DJ5203）
