Study On Low Tension Foam Oil Displacement System In Binary Flooding Reservoir

The Surfactant-polymer flooding pilot test had been carried out in the seven district of Gudong oilfield in Shengli oilfield from2003. It has made oil displacement effect remarkable. Surfactant-polymer flooding has become the main chemical flooding in Gudong oilfield. Now, most of blocks with surfactant-polymer flooding turned to the follow-up water flooding in Gudong oilfield. It has been faced with many problems such as rapid water cut increase and sharp decline of daily oil production. But the techniques after surfactant-polymer flooding is still in blank field. So it is necessary to adopt new technology and new method to control the production decline and further enhanced oil recovery.To achieve this, the study was conducted. Structure-activity relationships of foam agent is studied. To reduce the tension of oil-water interface, it had been carried out that the study of the relationship between the surfactant head group, tail base properties and reduce tension. On the other hand, to improve foaming ability, it had been studied that the relationship between surfactant headgroups, tail base, connection matrix properties and foaming ability from the requirements of foaming and foam stability of the gas-liquid interface. Combined with the characteristics of the reservoir, we studied the relationship between the temperature resistance, salt resistance and surface active agent structure. The design principle of low tension foam system was determined by that. It is developed to meet the requirements of the low tension foam system. Through the evaluation, the system is stronger resistance to high temperature ageing resistance, good resistance to salt, the divalent cations capacity. Simulation surfactant-polymer flooding in heterogeneous reservoir oil displacement experiment, it is showed that the system can improve the recovery after surfactant-polymer flooding.The system combined the advantages of foam flooding, polymer flooding and surfactant-polymer flooding and its advantages are obvious. This study enriched the theory of EOR and take the low tension foam flooding one step further in the theory and practice. This study will provide a new choice for enhanced oil recovery in reservoirs with high water cut and heterogeneity.