Study On Stress Sensitivity And Water Intrusion Mechanism Of Block - Shaped Gas Reservoirs In

The domestic and foreign researches on stress sensitivity and bottom water cut mechanism of carbonate fractured-vuggy gas reservoir are less. And research conditions and actual gas reservoir conditions differ greatly, lack the necessary experience and theoretical basis. This paper improved the design of experimental program to be more appropriate on the basis of domestic and foreign researches. This study for MX block stress sensitivity and bottom water cut mechanism of carbonate fractured-vuggy gas reservoir is based on physical simulation, supplemented by numerical simulation method. This research has established the permeability stress sensitivity test method under actual formation temperature and pressure conditions. Conducted6sets of fractured-vuggy full diameter core with different permeability levels stress sensitivity test by simulating the actual gas reservoir exploitation process. In view of the vertical connected fractured-vuggy bottom-water reservoir, carried out the bottom water cut test with three different sizes of aquifer, two kinds of different depletion rate. Finally, establishing a single well numerical simulation model of fractured-vuggy bottom-water gas reservoir to analyze different aquifer size, different aquifer energy and stress sensitivity on the influence of bottom water reservoir development effect.The major results made by the researches are as follows:(1)6fractured-vuggy full diameter core are strong stress sensitivity, stress sensitive permeability irreversible loss rate at about30%; fractured-vuggy core stress sensitivity and core porosity correlation is not big, and has good correlation with core permeability; conventional stress sensitivity test results and stress sensitivity test results with the geological conditions of high temperature and high pressure have certain difference;(2)The larger the bottom water size is, the higher the depletion rate is, the earlier the water breakthrough time is, the lower the gas production is, the faster the water content increase, the gas reservoir recovery degree is lower;(3)When there is large fractures connecting bottom water layer:the larger the aquifer is, the stronger the aquifer energy is, the lower the cumulative gas production is, the worse the stable yield is, the faster the water-gas ratio rise; under the influence of strong stress sensitivity, the cumulative gas production is lower, the stable yield is worse, the water-gas ratio has no obvious change.Research results have guiding significance to the fractured-vuggy gas reservoir development.