Moderate sand adding, pressurizing and acid fracturing method for improving fracture-vug type reservoir transformation effect

Abstract

The invention relates to a moderate sand adding, pressurizing and acid fracturing method for improving the fracture-vug type reservoir transformation effect. The moderate sand adding, pressurizing and acid fracturing method sequentially comprises the following steps of (1) establishing a target reservoir artificial fracture model, calculating to obtain the average fracture width of the artificial fracture model in a reservoir, taking 1/3 of the average fracture width as the upper limit value D of the particle size of a propping agent, and measuring the safe sand adding concentration R when the particle size of the propping agent is D; (2) determining a critical net pressure increase value of a natural fracture in the target reservoir with acid fracturing started; and (3) carrying out sand adding, pressurizing and acid fracturing construction on the target reservoir. According to the moderate sand adding, pressurizing and acid fracturing method, based on the characteristic that the net pressure is rapidly increased after sand is added into the fracture-vug type reservoir, a pump injection program is dynamically adjusted, a scheme is optimized in real time, residual acid after acid fracturing and the propping agent are transported to the far end of a fracture together, a near-end acid etching support and a far-end propping agent support are formed, the flow conductivity of a seepage channel in an acid fracturing affecting range is enhanced, the mining efficiency of a fractured-vuggy oil and gas reservoir is improved, and wide market application prospects are achieved.

Description

technical field [0001] The invention belongs to the field of oil and gas field development, and in particular relates to an acid fracturing process for moderately adding sand and pressurizing to improve the reconstruction effect of fracture-cavity reservoirs. Background technique [0002] Acid fracturing is one of the most important production stimulation measures for the efficient development of carbonate reservoirs. According to the difference in storage and seepage space, formulating an appropriate production stimulation process is conducive to improving the extraction efficiency and recovery level of resources. The matrix permeability of fractured-vuggy reservoirs is extremely low, and generally does not contain oil and gas, while the dissolution pores are mostly distributed along the weak surface structure. Some methods are used to induce acid fluid to leak out along natural fractures, open and drive natural fractures to expand, thereby increasing acid erosion. The numb...

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Problems solved by technology

Although these acid fracturing processes take into account the construction of the conductivity of acid-etched fractures, the optimization of the distal extension of fractures, and the timeliness of the conductivity of the fracture system, they are difficult to achieve when opening the weak surface structure of dissolved pores and driving natural fractures through acid fluid loss. The effect of expansion and other aspects is limited, which limits the development effect of acid fracturing technology on fractured-vuggy oil and gas reservoirs

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