Research On Enhanced Oil Recovery Of Foam Flooding And Effect On Environment

As a strategic resource, the exploitation and using of oil is very important. with rising of living standard.the need for oil is increased. Because oil isn't a rebirth resource, to enhance oil recovery of exploited reservoir oil recovery has become quite urgent, the technique of enhanced oil recovery (EOR) has been widely deserved extra attention by specialist. The reservoir resource can be applied to polymer flooding almost used up under the condition of the widely use of polymer flooding, but large numbers of residual oil leaves underground, the reservoir is more heterogeneous and residual oil scatters separated after polymer flooding, In order to enhance oil recovery further more strong driving system used to block up and flooding should be used. Because of the fourth kind of reservoir is strong heterogeneous, polymer flooding isn't suiTable . Hence, it is very necessary to study a new flooding method for the fourth kind of reservoir and after polymer flooding reservoir. As a good kind of flooding method, foam flooding was gradually known by people, because of its character of greatly improving the apparent viscosity of injected liquid, expanding swept area and enhanced oil recovery (EOR), it has been developed to be a future new EOR method.In this dissertation, the foam flooding evaluate method and system was established base on theory studies, excellent capability of foam agent and foam system was developed, the mechanism and capability for EOR of foam flooding, migration mechanism at porous media, compatibility with reservoir, affecting factor of EOR of foam flooding were also studied. together with the studies of the affecting to regime and reservoir of foam agent, the affecting to environment and facilities of injecting gas, the affecting to foam flooding system of injecting water, the affecting to production fluid of foam system ect., furthermore, the method to solve the relative problems were settled down. In this dissertation, the foamability and half foam life period of different surfactants was studied by means of rose-miles foam apparatus and scanner, include of anionic surfactants, positive ion surfactants, zwitterion surfactants, nonionic surfactants and negative-non surfactants. the surface and interfacial tension of foam agents was studied by using of interface tension apparatus, the foam stability and change rules under different conditions, the movement of foam, the rule of pressure transmission, the affecting of sealing characteristics of foam under the different ratio of gas injecting style, surfactant concentration ect. were studied by means of long slim tube simulation flow and high pressure watch window, by using microcosmic watch model to study the microcosmic mechanism of oil displacement; by using the tube models filled with silica sand and oil displacement test to study the capability of adjusting heterogeneous of foam between inner layers and interlaminations, the EOR of foam flooding after water flooding and polymer flooding, affecting factor and adapTable range of foam flooding. the method of metal piece rust were used to study the corruption of the apparatus by the foam agent and injecting gas; mass spectrum analyzing were utilized for determination consumption of foam agant on reservoir sands, the polymer's viscosity analyses were used to study its influence of wastewater and its component. The studies show that the polymer viscosity can be improved by adding chemical agent; the water quality sTable agent and product liquid treating agent was selected, and formed the producing liquid treating technique.Through the study of foamability, produce, block up and oil displacement tset in porous media of different foam system, high foam stability and low interface tension foam agent in high temperature and high salt reservoir has been developed; the foam flooding system matches with reservoir conditions has been developed too. the laboratory oil displacement test proved that the foam flooding can enhance EOR more than 25% after water flooding, and enhance EOR more than 10% after polymer flooding. After studying the interreaction between the foam system and environment, the problems were solved, and the pilot test of foam flooding proved a sharp increase of oil yield and reduce the cut of water. Laboratory experiments and pilot test proved that foam system can improve the heterogeneous of reservoir, great scope enhance oil recovery, the foam flooding is a kind of good new technique of tertiary oil recovery with a better future, Though deeper research for its key technique, it can be popular applied and disseminated., We believe foam flooding will be a good method for EOR with low cost, widly used and better future.