Method for carrying out of the hydraulic fracturing in the bearings aquifers or oil

摘要

Nine successive phases are employed. In the first, opening phase, a slug of pure, ballast-free fluid is used. Blockage follows, using fracturing fluid loaded with ballast. In a widening stage, pure fluid of defined volume pushes back the ballast of the previous phase to the edges of the future drainage to be installed. During this process, basal well pressure rises significantly. A filling phase follows, using ballast-loaded fracturing fluid. This is displaced using a plug of fluid. Closure takes place under no-flow conditions, for a sufficient interval to allow the fracture to close onto the supporting ballast. Cleaning follows. During discharge, the well regurgitates most of the fracturing fluid. The well, stimulated in this manner, is then re-introduced into service. The earlier fracturing phases are repeated until effective enlargement is detected from lasting rise in injection pressure. This is useful when fracturing breaks down the formation under increased injection pressure, at the end of the initial phase. In one or more phases employing a series of purely fluid plugs, one is of different composition; it may be pure or contain aggregate. The closure phase is preceded by a phase of abrupt discharge, in accordance with known procedures. Some or all ballast is mixed with fibers, or is coated adherently, to promote cohesion. The pump facilitates injection of small fracturing-gel flows, possibly including aggregate, into the well. These flows are controlled from the value of injection pressure at the base of the well, which is calculated or preferably measured.