Experimental study on evaluation of conglomerate reservoir support-type fracture conductivity in Xinjiang oilfield

The volume fracturing in the Mahu conglomerate reservoir, double-wing fractures are generated, resulting in inadequate proppant laying effect and low fracture conductivity. Experiments are designed to explore methods for improving the conductivity of conglomerate-supported fractures. Real triaxial indoor experiments are conducted to explore the effects of displacement, stress difference, and weak surfaces. The proppant diversion experiment explores the diversion ability under the conditions of single proppant, mixed proppant, and multiple sand-laying concentrations. Attention is focused on the impact of proppant embedding and fragmentation on conductivity. Research has shown that (1) stepped variable displacement fracturing is beneficial for controlling the generation of fractures. High displacement is beneficial for activating naturally weak surfaces. Small displacements are beneficial for identifying naturally weak surfaces and controlling the speed of crack extension. (2) Embedding of proppants mainly affects the conductivity of mixed base-supported conglomerates. Crushing mainly affects the conductivity of particles supporting conglomerate fractures. (3) Quartz sand or quartz sand-mixed ceramsite is used for conglomerate reservoirs with low effective closure stress and a complex matrix. Ceramic particles can are reduce the impact of fragmentation on the conductivity of particle-supported conglomerate reservoirs. Study aims to provide scientific guidance for the efficient development of the Mahu reservoir. •Experiments are employed to optimize the conglomerate reservoir fracturing.•Variable displacement fracturing is beneficial to activate the natural fractures.•A method for high conductivity support-type fracture was developed.•The basis for selecting proppant for the Mahu reservoir was formed.