Horizontal well back-mixing, fracturing and pumping-in method for compact reservoir oil deposit

Abstract

The invention provides a horizontal well back-mixing, fracturing and pumping-in method for a compact reservoir oil deposit. The horizontal well back-mixing, fracturing and pumping-in method comprisesthe following steps: a first prepad fluid stage, wherein the first prepad fluid is injected into a target measure layer, and the first prepad fluid is high-viscosity fracturing fluid; a second prepadfluid stage, wherein second prepad fluid is injected into the target measure layer and a supporting agent is added in a slug mode, and the second prepad fluid is low-viscosity fracturing liquid; a sand-carrying fluid stage, wherein sand-carrying fluid is injected into the target measure layer, and the supporting agent is continuously added, and the sand-carrying fluid is high-viscosity fracturingliquid. Through a back-mixing, fracturing and pumping-in process of sequentially injecting the fracturing liquid into the target measure layer according to a sequence, from high to low and then from low to high, of viscosity of the fracturing liquid, so that effective formation of a complex seam net is realized while multiple perforation clusters in horizontal wall multi-section fracturing are ensured to be fractured in a balanced mode, and therefore, modification area is increased, and the oil well yield is increased.

Description

technical field [0001] The invention relates to the field of petroleum exploitation, in particular to a pump injection method for reverse mixed fracturing of horizontal wells in tight oil reservoirs. Background technique [0002] Tight oil reservoirs are tight reservoir oil reservoirs, which depend on tight sandstone, tight limestone or carbonate rock, and their overburden matrix has low permeability, and there is no natural industrial production capacity of a single well. In my country's recoverable oil resources, tight oil accounts for 2 / 5. Due to the difficulty in developing tight oil reservoirs and high technical requirements, the development supporting technology is the guarantee for the effective development of tight oil reservoirs. Horizontal well staged fracturing technology is currently the The core technology of reservoir scale development. [0003] The existing staged fracturing technologies for horizontal wells mainly include the following two methods for the sti...

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Problems solved by technology

[0005] The present invention provides a reverse mixing fracturing pumping method for horizontal wells in tight oil reservoirs, which is used to solve the problem that the fracturing pumping method in the prior art cannot take into account the balanced initiation of perforation clusters and the effective formation of complex fracture networks, which is not conducive to the reconstruction The increase in volume affects the effective improvement of production capacity

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