Acid fracturing method of multiple acid injecting systems at deep carbonate rock formation

Abstract

The invention discloses an acid fracturing method of multiple acid injecting systems at deep carbonate rock formation. The acid fracturing method comprises the following steps of (1), evaluation of key reservoir parameters, (2) horizontal borehole trajectory determination, (3) determination of well completion mode and pressure separation mode, (4) oil and gas reservoir geological model establishment and production history fitting, (5) optimization of crack parameter systems, (6) optimization of acid pressure construction parameters, (7) different-viscosity acid-liquid independent injecting system design and connection with acid fracturing process, (8) high-viscosity fracturing fluid seam-making construction, (9) simultaneous injecting construction of different-viscosity acid liquid, (10) closed acid variable displacement injecting construction, and (11) replacement operation. By means of the acid fracturing method, the non-uniform etching degree of the inner wall of the crack can be improved, and the acid erosion crack conductivity of the deep carbonate rock formation under the high ground stress condition is improved, so that the effective cycle of the crack of the increase production by acid fracturing is prolonged, and the efficiency of economic development is improved accordingly.

Description

technical field [0001] The invention relates to the technical field of oil and gas field stimulation, and more specifically relates to an acid fracturing method for multiple acid injection systems in deep carbonate formations, and is especially suitable for acid fracturing stimulation operations in deep carbonate reservoirs. Background technique [0002] At present, the key to acid fracturing in deep carbonate formations is how to greatly improve the conductivity of acid-etched fractures under high geostress conditions. The usual practice is to use a combination of variable viscosity acid solution and variable displacement to improve the degree of non-uniform etching of the acid-etched fracture surface. The existing technology uses a single acid injection system on the ground, which has disadvantages: first, it is necessary to frequently switch the gates of acid tanks with different viscosities, which causes a lot of work and risks to the construction; The displacement in t...

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Problems solved by technology

[0010] However, the above patents and documents all have the disadvantages of the current combined construction mode of variable viscosity acid liquid and variable displacement: frequently switching the gates of acid tanks with different viscosities, the construction workload and risks are relatively large; the above-mentioned uniformity or displacement is not fundamentally changed. Near Uniform Etch Pattern

[0011] In summary, even if the multi-stage alternating injection mode of acid solutions with different viscosities is adopted, the above-mentioned uniform or near-uniform etching mode has not been fundamentally changed.

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