彭水区块页岩气水平井固井技术研究与应用

Cementing technology research and application of shale gas horizontal wells in Pengshui block

为了提高页岩气水平井固井质量,满足分段压裂需求,结合彭水区块固井技术特点,对水泥浆体系和固井工艺进行了研究。针对页岩气压裂需求,研究固井技术对策,并开展数值模拟,分析了压裂过程水泥石受力状态,形成降低弹性模量和提高水泥石抗拉强度的改性要求。利用力学分析结论,优选SFP弹塑性水泥浆体系,弹性模量降低>50%,抗拉强度提高>50%,满足分段压裂水泥石力学性能要求。为提高顶替效率,优选弹性扶正器及安放方案,利用高效溶剂型冲洗液体系和冲洗技术,以提高固井质量。水泥浆体系和工艺技术在彭水区块4口井开展应用,目的层固井质量胶结中等达到96%以上,压裂施工过程未见层间窜现象。

In order to improve horizontal shale gas well cementing quality to meet the needs of staged fracturing, and combined with the characteristics of cementing technology in Pengshui block, slurry system and cementing process are analyzed. Aiming at the de mands of shale gas fracturing, the cementation technology strategy is researched, the numerical simulation is carried out and the stress state of cement during fracturing is analyzed, so that the modification requests of elasticity modulus reducing and the cement tensile strength improvement are formed. By using mechanical to analyze the conclusions, SFP elastoplasticity slurry system is opti mized. The elasticity modulus reduces greater than 50 % and the tensile strength improves greater than 50 %, which satisfy the ce ment mechanical performance requirements of staged fracturing. In order to improve the displacement efficiency, the elastic central- izer and its installation schemes are optimized. Efficient solvent-based fluid system and flushing technique are used to improve the cementing quality. Slurry system and technology are applied in four wells of Pengshui block. Medium situation of cementation of ce menting quality in the target layer is above 96 %. No interlayer channeling exists in the fracturing process.