Research On Integrated Technology Of Oil Stimulation And Sand Control For Heavy Oil Reservoirs In Eastern South China Sea

The eastern south China Sea reservoir has shallow burial,loose structure,large wax content,strong sand carrying capacity and serious sand production.Improving oil well production and achieving sand control have become the key of unconsolidated sandstone reservoir exploitation.Aiming at the reservoirs in the eastern South China Sea,this paper studies the fracture initiation,propagation,and filling process from the perspective of production stimulation and sand control.Firstly,this paper establishes the fracture initiation displacement model of perforated wells in unconsolidated sandstone in the eastern South China Sea,and analyzes the influence of rock porosity,fracturing fluid viscosity,formation permeability,reservoir thickness,perforation density and perforation depth on the fracture initiation displacement model.Then,Abaqus is used to simulate the fracture propagation of unconsolidated sandstone reservoir,and the fracture morphology of unconsolidated sandstone and tight sandstone is compared during the fracturing process.Meanwhile,the influence of mechanical parameters on fracture morphology of unconsolidated sandstone during fracture propagation is analyzed.The results show that fractures formed in unconsolidated sandstone reservoir are elliptical,while those formed in tight sandstone are sharper and thinner with the smaller fracture width.To evaluate the fracturing effect,the proppant index method is used in this paper,and the influence of proppant embedding and formation sand migration is considered,then the optimal fracture geometry parameters can be obtained by iterative solution.The results show that the deeper the sand migration and proppant embedment lead to the optimal fracture length decreases,the optimal fracture width increases,and the actual production ratio decreases.Finally,considering the geological characteristics of reservoirs in the eastern South China Sea,the completion method of Frac-Pack is selected.The construction parameters of the oil reservoir in the eastern South China Sea were optimized by the leak-off model,fracture propagation model and sand adding program.The effects of reservoir pressure,permeability,fracturing fluid viscosity,comprehensive leak-off coefficient and vertical in-situ stress on construction parameters are also analyzed.The results show that the construction parameters are significantly affected by formation permeability,comprehensive leak-off coefficient and vertical in-situ stress,but are less affected by formation pressure and fracturing fluid viscosity.These results have certain reference significance for the actual construction on site.