Process for hydraulically fracturing a geological formation along a predetermined direction

摘要

This process comprises positioning along a predetermined direction two walls penetrating a geological formation to be fractured. During a preliminary period a predetermined amount of hydraulic fluid in injected. During a preliminary period/hydraulic fluid is injected simultaneously into both wells during for a sufficient time interval at a pressure insufficient to fracture the formation, either at a substantially constant flow rate, or in a stepwise manner at progressively increasing pressure levels. This preliminary injection is followed by the injection of hydraulic fluid into at least one of the wells at a pressure higher than the pressure of fractuation of the formation.