川西致密砂岩气藏水平井高效分段压裂技术及应用

Efficient Staged Fracturing Technology for Horizontal Well of Tight Sandstone Gas Reservoir in Western Sichuan and its application

针对川西致密砂岩气藏的地质特征,从如何建造高效复杂缝网的目标出发,建立了基于三种砂体分布特征的压裂模型。以最小阻隔层厚度划分渗流单元,基于单个渗流单元采用数值模拟手段精细优化裂缝条数及单条裂缝形态参数,形成了基于独立渗流单元的水平井精细分段压裂优化技术;在裂缝系统如何有效长期保持方面,建立支撑剂非连续铺置的评价方法,形成了便捷、低成本的脉冲纤维加砂压裂工艺,同时通过实验评价储层伤害,建立起一套防膨降水锁压裂液体系,降低了天然气从基质向裂缝的流动阻力,使人工裂缝参数与砂体展布、储层渗流能力相匹配。现场应用效果较好,对国内外难动致密砂岩气藏的有效开发具有借鉴意义。

According to geological characteristics of tight sandstone gas reservoirs in Western Sichuan, a fracturing model based on three kinds of sand body distribution characteristics is established in order to construct efficient and complex fracture net. The seepage unit is divided by the minimum thickness of barrier layer. Based on a single seepage unit, the number of fractures and the parameters of single fracture shape are refined and optimized by numerical simulation, and fined sectional fracturing optimization technology for flat wells is formed based on independent seepage unit. In the aspect of how to effectively maintain the fracture system for a long time, an evaluation method of discontinuous proppant placement is established, and a convenient and low-cost pulse plunger sand fracturing technology is formed. At the same time, reservoir damage is evaluated by experiments, and a set of anti- swelling and dewatering locking fracturing fluid system is established, which reduces the flow resistance of natural gas from matrix to fracture. Artificial fracture parameters are matched with sand body distribution and reservoir seepage ability. The field application results are remarkable, which can be used for reference for the effective development of hard-to-move tight sandstone gas reservoirs at home and abroad.