Water-control effect-enhancing fracturing method of carbonate reservoir

Abstract

The invention discloses a water-control effect-enhancing fracturing method of a carbonate reservoir. The water-control effect-enhancing fracturing method comprises design references and methods of such technologies as a fracturing fluid system (a cation fracturing fluid and a water-in-oil emulsion fracturing fluid), a fracturing process (optimal water control and block design, directional sanding and large-scale fracture forming) and a production scheduling system (high pressure limiting liquid drainage and pressure limiting production). The water-control effect-enhancing fracturing method adopts the basic principle that in the fracturing construction process, a highly-flow-guiding fracture with oil passing and water blocking performance is formed, water blocking of a water breakthrough oil reservoir is realized by virtue of the hydrophobicity of a modified propping agent, and water in the fractured water layer can be effectively controlled not to flow into a shaft through the fracture, so that the water control and block performance of the hydrophobic propping agent are given into full play, the production stimulation effect of carbonate reservoir fracturing is improved, the water breakthrough time after fracturing is pushed back, the water yield after fracturing is reduced and the effective fracturing period is prolonged.

Description

technical field [0001] The invention relates to the field of oil and gas field development, and more specifically, to a water-controlling and efficiency-enhancing fracturing method for carbonate rock reservoirs in the field of oil and gas field development. Background technique [0002] Carbonate reservoir is controlled by the fracture-cavity system formed by tectonic-karstification, and is a composite oil-gas reservoir formed by the superimposition of multiple fracture-cavity bodies in space. On the plane, reticular dissolution channels, subsurface flow caves, and fracture-cave bodies in the surface corrosion zone intersect with each other and are distributed in a layered and multi-layered system. Vertically, network-like multi-layer dissolution channels, subsurface flow caves, and surface dissolution zones are intermingled to form fracture-cave aggregates. In terms of reservoir physical properties, carbonate reservoirs have low matrix permeability and strong isolation bet...

AI Technical Summary

Problems solved by technology

The main limitations of the above technical measures are as follows: ①The length of acid-etched fractures is limited, and it is difficult to achieve the purpose of connecting fractured (cavity) reservoirs in the far-well zone; ②High-angle fractures are developed in carbonate reservoirs. The interlayer stress difference is small, the fracture height is difficult to control, and the effect of delamination and layer reversion is poor; ③Selective water plugging technology has a short validity period to reduce the water yield of oil wells, and once the water body is connected, water flooding will occur; ④Control the fracturing scale and Measures to control fracture height such as displacement parameters make the construction effect limited, and it is impossible to communicate with the reservoir

[0006] All in all, the development of fractured-vuggy carbonate reservoirs is currently limited by the main means, the length of acid-etched fractures formed by acid fracturing is limited (generally considered to be less than 120m), and the penetration distance of fractures is limited, which cannot effectively communicate with fracture-vug development zones far away from wells. However, it is difficult to stimulate and develop multiple target reservoirs with different physical properties by using general acid fracturing with horizontal downhole packers, and the stimulation effect is unsatisfactory; The research and application of well selection and layer selection, fracturing fluid system optimization, proppant system screening, process technology design and other aspects can ensure the formation of long effective fracture length and high fracture conductivity. Improve the probability of communicating with effective reservoirs farther away, so as to improve the effect of improving reservoirs

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