减轻深层低渗储层水锁损害的钻井液研究与应用

准噶尔盆地中部的深层低渗储层西山窑组具有含水饱和度高、孔喉细小、渗透性差、结构复杂、非均质性严重、油气流动阻力大、常伴有天然裂缝等特点.岩心流动实验结果表明,水锁损害是该低渗透孔隙型砂岩储集层的主要损害因素之一,渗透率损害率为49.3%～89.2%.研究了多元醇类处理剂降低滤液表/界面张力的特性,应用防液锁技术、理想充填理论及d<,90>规则研发了具有侵入量低、防水锁和防塌能力强、润滑性好等特点的高性能多元醇钻井液.现场应用表明,该钻井液既能满足超深井安全快速钻井的需要,也有助于保护深层低渗油气藏,对其它区块超深井钻井完井液的设计有一定借鉴意义.

Research and Application of Drilling Fluids to Mitigate Porosity Impairment of Deep and Low Porosity Reser-voirs

The deep, low permeability Xishanyao Formation in the middle of the Junggar Basin is character-istic of high water saturation, thin pore throats, poor permeability, complicated formation structure, het-erogeneity, high flow resistance to oil and gas flow, as well as natural fractures etc. Core flow experiments showed that water block was one of the major factors causing formation permeability impairment; water block resulted in permeability impairment of 49.3%～89.2%. Laboratory studies have been done on the function of polylol additives in lowering the interracial tension between mud filtrate and formation rocks. A polylol drilling fluid was designed using water block technology, ideal packing theory and the so-called D<,90> rule. This fluid has low filtration invasion, strong inhibitive capacity and good lubricity. Watre block can be greatly minimized. Field application gave birth to a satisfactory result. The idea of the design of this mud can be brought to the mud design in other areas with similar formation features.