Study On The Migration Law And Injection Of Foam Gel In Offshore Oilfields Parameter Optimization

The current application of the EOR technology in offshore oil fields suggests the chemical flooding is one of the main directions of EOR in China.However,after polymer flooding,the water cut of some oilfields rises continuously,so it is necessary to study the EOR technology that is applied after polymer flooding.By using the physical and chemical properties of the foam gel system displaced in physical crosslinked gel,oil displacement mechanism,core displacement experiment and establishment of mechanism model,it analyzes and evaluates the displacement effect of foam gel system and optimizes the injection parameters of foam gel system.As a result,it puts forward a set of feasible injection schemes.Having studied the physical and chemical properties of physical crosslinked gel,it finds that the physical crosslinking gel is a kind of physical gel that by associating molecular chains,forms the supramolecular aggregate structure to obtain the characteristics of"gel".On the surface,the physical crosslinking gel is similar to the traditional chemical crosslinking system,but the principle and the mechanism of them are completely different.The structure fluid with physical crosslinking(non-chemical crosslinking)has high-viscoelasticity and can replace the traditional chemical crosslinking gel to be using in the form foam gel system.Through analyzing the performance of the foam gel system,it finds that the higher the permeability of the foam gel in the test range,the higher both the capacity of the foam gel to establish the drag coefficient and the residual resistance coefficient,which means it is especially suitable for plugging and selectivity of high-porosity and high-permeability and also has good conductivity and effective deep-transmission.By the analysis of the injection parameters of the foam gel system,the best injection scheme is selected.The total injection volume is 0.28PV,the injection rate is0.03PV/a,the gas-liquid ratio of the system is 1:1,it adapts the injection of gas and liquid simultaneously,and its alternate period is 90 days.According to optimization scheme,it conducts simulation.The simulation results show that when the water cut reaches 98%,the foam gel flooding is 5.4%higher than that of the continuous water flooding.In terms of oil production,the continuous water flooding oil production decreased constantly,from20m~3 per day to 6.5m~3 per days.After adopting foam gel flooding,there is an obvious increase in the oil production volume,reaching 47.5m~3 per day,then stable at 14.1 m~3 per day.As for water cut,it also suggests that the water cut reduced obviously,and can decrease to 56%,after the foam gel flooding.