Research And Application Of Chemical Water Shut-off Agent In Gasi Oilfield

With the continuous deepening of the water injection development in the Gasi Oilfield,the contradiction between the reservoir plane and the layer is unusually outstanding.It is characterized by low level of water drive,severe waterlogging,and flooding of oil wells.And the oil wells are characterized by multiple layers of water,low success rate of water plugging,short validity periods,drop in liquid production and high water content.In order to improve the water-driven reserves,the research and application of mechanical water shut-off and chemical water shut-off were mainly applied and improved in recent years.However,due to factors such as high temperature,high salinity,corrosion,scaling,and deterioration of well conditions,the success rate of water plugging process technology is low,and the effective period is short,causing greater damage to the reservoir and causing permanent damage.Therefore,this paper has carried out the following work:(1)The composition and reservoir characteristics of the Gasi N1-N21 reservoirs were analyzed,the potential damage factors of the reservoir were summarized,and the water plug adaptability of reservoir were summarized.(2)The optimization experiments of low-density cement plugging agent,cement calcium oxide plugging agent,and calcium oxide cement blocker for ultra-fine cement were carried out.Through comparative experiments,an optimized formulation system under different density conditions was obtained and evaluated.(3)The emulsified oil-soluble resin blocking agent and the strong gel blocking agent were screened and their plugging performance evaluation experiments were carried out.The results show:the emulsified oil-soluble resin plugging agent has good oil-insoluble water insolubility and good stability,and the plugging rate can reach 93%.After the strong gel blocking agent is plugged,the residual resistance coefficient is more than 10,and the high,medium and low permeability formations can be effectively plugged and the performance is good.(4)The inorganic blocking agent system formulation,emulsified oil-soluble resin blocking agent formulation and strong gel blocking agent formulation will be applied on site,The results show:the inorganic blocking agent formula and the strong gel blocking agent formula have good effect on the on-site well test,which has a good effect of increasing oil and water.The results of this study have been validated in the field,which is of great significance for the sustained and stable production of the GaSi oilfield.