Experimental Study On Reservoir Characteristics And Charging Medium Optimization In A Tight Oil Block In Daqing

In recent years,tight oil has become a hot spot in the development of global unconventional oil and gas.The staged fracturing of horizontal wells is an effective technical means for the development of low-permeability/tight reservoirs,and is gradually accepted by major oil fields and used in exploratory tests.The staged fracturing horizontal well has a high initial production rate during depletion mining.With the increase of mining time,the production declines significantly,and the reservoir pressure drops rapidly.It is urgent to effectively supplement the formation energy to achieve stable production.In this paper,a tight oil horizontal well development demonstration area in Daqing Oilfield was taken as the research object,and the geological characteristics of the reservoir were studied by mercury intrusion method,X-diffraction,field emission scanning electron microscope,nuclear magnetic resonance and other technical methods,and then similar principles and dimensionless were used.The diversion capability designs an artificial three-dimensional physical model that meets the conditions.A large-scale three-dimensional high-temperature and high-pressure physical simulation experimental method for supplementing energy in a staged fracturing horizontal well was created by establishing a three-dimensional large model physical simulation experiment method for evacuating saturated water and designing a comprehensive energy storage tank to simulate infinite formations.On this basis,three types of reservoirs with different fracture scales under different charging media were compared and analyzed.The reasonable charging media in the study area were optimized and evaluated.The results show that the pore throat radius of tight oil reservoirs in the study area is mainly submicron level,with high clay mineral content and low degree of micro-fracture development;different charging media can improve the recovery factor to a certain extent,but the effect of carbon dioxide Relatively good,the main contribution of the role comes from the conversion of the dead oil zone of the reservoir into a non-linear seepage zone;in terms of the energy supplement work system,the reasonable time of the indoor huff and puddle well is 24h,and the effect of multiple huff and puff oil recovery is better than that of the single Throughput,the maximum throughput round does not exceed 3rounds.