页岩气开发钻井液技术研究

由于页岩气井特殊的储层特征,对钻井液的抑制性以及润滑性等提出了很高的要求,油基钻井液虽然能够满足页岩气水平井钻井的需要,但其环保问题以及成本问题等成为制约其大规模应用的瓶颈.为此,针对页岩气储层的特点,室内开展了适用于页岩气水基钻井液的抑制剂、增粘剂、降滤失剂以及润滑剂的优选,形成了一种高性能的页岩气水基钻井液体系.并对该体系进行了综合性能的评价,结果表明,体系具有良好的流变性能,在90 ℃下老化16 h后的高温高压滤失量仅为5.6 mL,摩阻系数为0.11;体系的钻屑热滚回收率达到了98.88%,具有良好的抑制性能;体系在150 ℃高温下老化后仍可保持较好的流变性能和降滤失性能,表明体系具有较强的抗温能力;体系在加入5%的粘土和氯化钠后流变性变化不大,说明体系具有较强的抗污染能力.说明优选的高性能页岩气水基钻井液体系具有优良的综合性能,能够满足页岩气水平井钻井的需要.

Study on Drilling Fluid Technology for Shale Gas Development

Due to the special reservoir characteristics of shale gas wells, the requirements for drilling fluid inhibition and lubrication are very high. Although oil-based drilling fluid can meet the needs of shale gas horizontal well drilling, its environmental problems and cost problems become a bottleneck restricting its large-scale application. In this paper, based on the characteristics of shale gas reservoirs, suitable inhibitors, tackifiers, filtrate loss reducers and lubricants for the shale gas water-based drilling fluid were screened out, and a high-performance shale gas waster-based drilling fluid system was developed, comprehensive properties of the system was evaluated. The results showed that the system had good rheological properties, and the high temperature and high pressure filtrate loss was only 5.6 mL and the friction coefficient was 0.11 after aging at 90 ℃ for 16 h. The cutting heat roll recovery reached 98.88%, and the inhibition performance was good. After the aging system at 150 ℃, the system could maintain good rheological properties and filtrate loss reduction performance, which indicated that the system had strong resistance to temperature. After adding 5% clay and sodium chloride in the system, its rheological change was little, indicating that the system had a strong anti-pollution ability. The results have proved that the high performance shale gas water-based drilling fluid system has excellent comprehensive performance and can meet the needs of shale gas horizontal well drilling.