Method for experimentally determining carbonate rock oil and gas reservoir acid fracturing fracture conductivity distribution

Abstract

The invention discloses a method for experimentally determining carbonate rock oil and gas reservoir acid fracturing fracture conductivity distribution. The method comprises the steps that an acid fracturing simulator FracproPT is adopted for simulating the down-hole acid fracturing fracture extending and acid etching process during acid fracturing, and fracture width distribution, fracture height distribution, temperature distribution and acid liquor mass concentration distribution data in the hydraulic fracture length direction are obtained; in the hydraulic fracture length direction, fracture width, fracture height and temperature data of total 10 feature points with the acid liquor mass concentration being 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10% of the initial mass concentration are selected; acid injection displacement of the oil field site scale is converted into acid injection displacement of the laboratory scale; according to the acid liquor mass concentration data of the 10 feature points, acid liquor used for an experiment is prepared; and the acid etching process is simulated, the conductivity under the condition of reservoir closed pressure is tested experimentally, and a distribution diagram of the acid etching fracture conductivity in the fracture length direction under the reservoir condition is drawn. The method is reliable in principle and simple and convenient to operate and has wide market prospects.

Description

technical field [0001] The invention relates to a method for experimentally determining the distribution of conductivity of acid fracturing fractures in carbonate oil and gas reservoirs in the field of petroleum engineering. Through experiments, the distribution of conductivity of underground acid fracturing fractures along the direction of fracture length is tested to accurately evaluate the conductivity of underground acid fracturing fractures. ability to improve the stimulation effect of acid fracturing in carbonate oil and gas reservoirs. Background technique [0002] my country's marine carbonate reservoirs are widely distributed, with 50 marine basins and an exploration area of ​​about 455×10 4 km 2 , the amount of oil and gas resources is 380×10 8 t oil equivalent. In recent years, large-medium-sized marine carbonate oil and gas fields have been successively discovered in the Sichuan Basin, the Ordos Basin, and the Tarim Basin. By the end of the "Eleventh Five-Year...

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Problems solved by technology

Numerical simulation method is corrected by empirical formula, which has great uncertainty and low accuracy

The experimental method is the most direct method to obtain the conductivity of acid-etched fractures, but limited by the scale of the current experimental rock sample (the current experimental rock sample: length (140-180) mm × width 38 mm × thickness (15-50) mm), The experimental results only reflect the conductivity near the wellbore, and it is difficult to reflect the conductivity along the entire fracture length

At present, there is no experimental method at home and abroad to evaluate the distribution of conductivity of acid-etched fractures along the length direction of hydraulic fractures, which directly leads to blindness in the selection of acid fracturing process measures and acid fracturing parameters in carbonate reservoirs, which affects the acid fracturing effect. Increased economic cost of acid fracturing

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