A method for increasing production and controlling water in sandstone gas reservoirs with bottom water

Abstract

The invention relates to the technical field of oil and gas reservoir hydraulic fracturing transformation, in particular to a method suitable for production increasing and water controlling of a sandstone gas reservoir of a bottom water layer. The method comprises the following steps that A, characteristic parameters of a longitudinal ground stress section and a natural fracture are evaluated; and B, control factors of the fracture forming height and the supporting height are analyzed, specifically, 1 a reservoir stratum is pretreated through an acid fluid, and longitudinal over-extension of the initial fracture height is controlled; 2 an RPM fracturing fluid serves as a fracturing prepad fluid to be injected into a stratum for water proofing; 3-5 according to the variable parameter combination fracturing process technology, variable displacement construction is conducted through different viscosity of liquid carrying propping agents with different grain diameters and densities, fracture extending and reasonable and effective laying of the propping agents are controlled; 6 the propping agents in a wellbore are completely displaced to a fracture opening through low-viscosity liquid such as low-viscosity slick-water; and 7 if the bottom water layer is fractured in construction, after fracturing construction is completed and a fracture is closed, the weighted RPM fracturing fluid is injected into the fracture through a pressure limiting mode, so that water in the bottom water layer is prevented from going upwards.

Description

technical field [0001] The invention relates to the technical field of hydraulic fracturing reconstruction of oil and gas reservoirs, and more particularly relates to a method suitable for fracturing and effectively controlling water in sandstone gas reservoirs with bottom water. Background technique [0002] Due to the generally poor physical properties of tight sandstone gas reservoirs with bottom water, most gas wells must undergo fracturing to obtain industrial productivity. Fracturing technology has become one of the core technologies for production stimulation and effective development of such reservoirs. Since the tight sandstone bottom water gas reservoir is close to the bottom water layer, it is easy to communicate with the water layer during the fracturing process, resulting in a substantial increase in the water output after fracturing, and the serious water lock effect, which restricts the effective production of gas. At present, the fracturing stimulation of thi...

AI Technical Summary

Problems solved by technology

[0003] 1) The fracturing design and construction scale are generally too large, causing the fracture height to extend downward excessively in the longitudinal direction;

[0004] 2) The fracturing operation displacement is too large, which can easily cause the bottom hole pressure to accumulate and rise rapidly, resulting in too fast and high fracture height extension, especially when the stress difference between the fracturing target reservoir and the upper and lower interlayers is unbalanced, Excessive displacement will cause the fracture height to extend faster to the vertical direction with small stress difference;

[0005] 3) The design and application of fracturing fluid viscosity is not reasonable enough. Most of the fracturing construction process uses a single fracturing fluid system or a fracturing fluid system with one viscosity, and the viscosity of fracturing fluid is generally high, resulting in fracture height. excessive extension of

[0006] 4) The optimization and optimization of proppant is not enough. The type of proppant used in the construction is relatively single, and the density is relatively high. Once the high is out of control and the water layer is pressed, the conductivity of the fracture supported by the proppant in the water layer will be too high , the water conduction capacity is too large, which intensifies the water lock effect