Experimental evaluation method for reservoir matrix damage

Abstract

An experimental evaluation method for reservoir matrix damage comprises the following steps of evacuating a rock sample, soaking the rock sample in preset simulation experiment saline water for a first preset duration, putting a rock core into a holder, and adjusting the confining pressure to preset confining pressure; reversely displacing the rock core, and measuring the reference permeability of the rock sample to obtain a first permeability; using preset active water to positively displace a first preset number of pore volumes, then stopping displacement, keeping the temperature and the pressure to enable the preset active water to react with the rock sample for a second preset duration, using the preset simulation experiment saline water to reversely displace the rock core, and determining the permeability of the rock core after water sensitivity occurs to obtain a second permeability; determining a permeability change damage rate caused by water sensitivity according to the first permeability and the second permeability to obtain a first permeability change damage rate. According to the method, the quantitative evaluation of the damage of the fracturing fluid to a reservoir matrix can be realized, and the main damage and the size thereof can be accurately graded, so that an accurate and reliable theoretical and data basis can be provided for the optimization direction of the fracturing fluid.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploration and development, in particular to an experimental evaluation method for reservoir matrix damage. Background technique [0002] Due to the characteristics of low porosity and low permeability, tight sandstone gas reservoirs must be fracturing to realize their economic productivity. Fracturing fluid is an indispensable technical measure of fracturing technology, and the intrusion damage of its gel-breaking fluid filtrate to the reservoir is one of the key factors affecting the release of production capacity. Effective evaluation of the damage composition and size of the fracturing fluid gel breaker to the reservoir matrix can provide a more reliable basis for the optimization direction of the fracturing fluid. [0003] At present, the alkaline guar gum water-based fracturing fluid system is usually used for reservoir stimulation in tight sandstone gas reservoirs. Water-sensitivity,...

AI Technical Summary

Problems solved by technology

Water-sensitivity, alkali-sensitivity, and fracturing fluid gel-breaking fluid filtrate core damage experiments are used to evaluate the damage that fracturing fluid may cause to the reservoir, but the sensitivity evaluation in the industry standard only considers a single factor, gel-breaking fluid filtrate The core damage experiment reflects the total damage

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