Method for blocking water for fracture and hole type reservoir

Abstract

The invention provides a method for blocking water for a fracture and hole type reservoir, which is particularly applicable to high-mineralization fracture and hole type reservoirs. The method includes that blocking agent with following ingredients is selected, the ingredients of the blocking agent include, by mass percent, from 5.24 to 9.36% of cement, from 3.03 to 5.35% of microsilica, from 4.01 to 5.43% of sodium bentonite, from 0.52 to 0.55% of polymeric dispersant, from 0.17 to 0.40% of retarder, from 0.0008 to 0.0011% of sodium carbonate aqueous solution by sodium carbonate and the balance water, and water cement ratio of the blocking agent ranges from 4.07 to 6.28; the blocking agent is injected into an oil well according to output volume of 300-800L / min, and after soaking for 72 hours, the well is opened and begins production; and the use level of the blocking agent is equal to 1 / 2 to 2 / 3 of the use level of fracturing liquid during acid-fracturing of an analog crack or communication of reservoir bodies, and is calculated by 5-20m3 / m of a blocking well section for a well without being in acid-fracturing. The density of the blocking agent ranges from 1.09g / cm3 to 1.14g / cm3 and is not changed before and after solidification, solidification strength ranges from 0.22 MPa to 0.43MPa, leakage of the blocking agent due to the density reason cannot be caused in a water blocking process of the fracture and hole type reservoir, and the blocking agent can effectively stay on an oil-water boundary, and selectively blocks a water outlet channel.

Description

technical field [0001] The invention relates to the field of chemical water shutoff of oil reservoirs, in particular to a plugging agent suitable for fracture-cavity oil reservoirs and a method for using the plugging agent to shut off water in oil reservoirs, which can realize effective treatment of oil wells with high water content. Background technique [0002] The petroleum geological reserves and production of carbonate reservoirs account for 50%-60% of the world's petroleum geological reserves and production, and have always occupied an important position in the development of oil and gas fields at home and abroad. Carbonate reservoirs are of various types, mainly including large-scale uplifts, reefs, buried hill reservoirs, etc. The main reservoir space types include primary pores, secondary pores, dissolution pores and fractures, and some oil and gas reservoirs develop large dissolution fractures , hole system. [0003] The reservoir shape of carbonate reservoirs det...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to overcome the defects of the existing plugging agent used in fracture-cavity reservoirs such as high density, contradiction between strength and selectivity, and provide a method for water plugging in fracture-cavity reservoirs. During the water plugging process of cave-type reservoirs, the plugging agent will not be lost due to the density, and the plugging agent can effectively stay and block the water outlet channel; the oil and water selectivity in the plugging water and the strength of the plugging agent are high, realizing high-strength selection Sexual water blocking

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