致密气藏低伤害压裂液研究及应用

致密气藏通常具有低孔、低渗、低压、强水锁等特性，减少外来液体侵入储层，加快压裂液返排，提高压裂液返排率，将直接影响压后的单井产量。针对鄂北塔巴庙地区上古生界气藏石盒子组盒1段和山西组山1段，在充分认识储层地质特征的基础上，对N2增能水基压裂液进行了大量的室内研究，以尽可能降低由于压裂液侵入储气层而造成的伤害。试验表明，N2增能水基压裂液能较好地降低储层喉道毛细管的界面张力，有利于压裂后残液的返排，降低了对储层造成的伤害，其性能指标满足压裂工艺对储层改造的要求。通过现场实施，该压裂液配方体系能较好地满足压裂工艺及储层的物性，提高了压后压裂液返排率，取得较好的单井产量。

Research on low damage fracturing fluid in tight gas reservoirs and its application

Tight gas reservoirs feature in low porosity, low permeability, low pressure and strong water locking. The single-well productivity after fracturing will be negatively influenced by reducing the extraneous fluid invasion, accelerating the back-discharge of fracturing fluid, and increasing the back-discharge rate. Based on fully recognizing the geological features of the He1 member of Shihezi formation and the Shan1 member of Shanxi formation of the Upper Paleozoic gas reservoir in Tabamiao area of northern Ordos Basin, a lot of lab research is conducted on the N2 enhanced water based fracturing fluid, aiming at as much as possible lowering the damage caused by the invasion of fracturing fluid into the reservoir. Lab research shows that the N2 enhanced water based fracturing fluid can be used to better reduce the surface tension in the capillaries in the reservoir pore throats, favorable for the back-discharge of residual fracturing fluid, lowering the damage to the formation. The properties of the fracturing fluid meet the requirement of the fracturing process on reservoir reconstruction. Field application indicates that the formula system of the fracturing fluid could better meet the requirements of the fracturing process and the physical properties of reservoirs, increasing the back-discharge rate of the fracturing fluid after fracturing, and realizing higher single-well productivity. 