Study On Water-flooding Pressure System And Change Of Production Gas-oil Ratio In Western Wells In Central Area

With the deepening of Sa-Zhong development area and the change of well network,the underground pressure field and the fluid field have undergone profound changes.The law of oil field development and the main technical parameters have changed obviously,the relationship between oil and gas also changed.The production gas oil ratio in multi oil block is rising and the difference of production gas oil ratio between different factories is large.The interference of oil,gas and water is aggravated by high gas production,and the oil flow is worse after degassing,which affects the overall development effect of oil field.How to establish an effective and reasonable pressure system to guide the production and injection proration of the target area,to determine the relationship between pressure system and production gas oil ratio to control the relationship between oil and gas,and to develop the oil field effectively and rationally according to the current situation is the most important work of the water-flooding reservoir.From the point of view of the whole pressure system,a numerical simulation method is used to study the reasonable formation pressure.The results of different formation pressure schemes have been designed to show that the recovery is maximum when the formation pressure is near the saturation pressure.The reservoir engineering method is used to verify the numerical simulation results,and the recovery under the different formation pressure under the economic limit water cut is calculated,and the conclusion is consistent.The injection pressure of water well and the flow pressure of oil well directly affect the formation pressure.In view of the reasonable injection pressure and flow pressure of different oil layers and different well nerwork in the western part of the middle area,the orthogonal design scheme of injection pressure and oil well flow pressure is designed.The reasonable injection pressure limit and the corresponding reasonable flow pressure boundary under different oil well wells are calculated.Based on the study of reasonable pressure system,the reasonable injection production ratio and the production and injection proration at the present stage is studied,and which injection production ratio should be adopted when the formation pressure is low to reach the reasonable formation pressure range is studied and simulated.The overall analysis of the reasonable pressure system shows that when the formation pressure is too low,the liquid production is reduced,the crude oil is degassed in a large range,the viscosity of the crude oil is increased,and the oil and water flow is changed to three phase flow of oil and gas and water,and the development effect is worse.In recent years,the gas and oil ratio in the Sa-Zhong development area has been continuously rising,which also affects the overall development effect of the oil layer.Therefore,the influence factors of the production gas oil ratio are studied by the numerical simulation method,and the multiple regression model of gas oil ratio is established,and the relationship between gas oil ratio and pressure drop speed,pressure drop level and gas recovery degree is regressed,and the overall law of production gas oil ratio is described.