Study On Surfactant / Foam Flooding System In Xidariya Reservoir

Xidaliya reservoir is a high temperature(100℃) and high salinity(20.48×104mg/L, divalent ion1.15×104mg/L) reservoir whose heterogeneity is serious. Because of the surfactant flooding can’t control the mobility, it can’t increase the degree of swept volume. And the polymer will degrade and reduce viscosity on the condition of Xidaliya reservoir.Aim at the above problems, a foam system(HK) and a low interfacial tension system(YF) that are on the basis of new surfactant are selected. HK can control the mobility and increase the degree of swept volume; YF can increase the microscope displacement efficiency, so the combination of HK and YF can reach the best recovery. Long-term resistance to temperature and salt of HK was researched, and the impact of oil on foam stability was explored. Long-term resistance to temperature and salt of YF was researched, and the emulsification, wettability, adsorption are explored. In addition, the impact between HK and YF was researched. Through physical simulation experiments, the effect of the viscosity of liquid and Jamin action of foam to resistance factor and the effect of the degree of IFT to recovery are researched. At last, the reasonable injection method of anisotropic layer has been optimized.On the condition of100℃、20.48×104mg/L, the volume of the HK foam is560mL and the drainage half-life is43.33min. Long-term resistance to temperature and salt of HK is well and the drainage half-life is as25%longer as the contrast sample. The impact of crude oil on the foam stability experiments showed that:foam stability was greatly influenced by crude oil and the higher the content of lightweight is, the worse stability the foam is. When foaming after oil added into the liquid the foam stability reduced greatly. The IFT between YF and Xidaliya oil is3.16×10-4mN/m. Long-term resistance experiments of YF show that:the IFT stays in the degree of10-4mN/m in45days,10-3mN/m in90days. Emulsification experiments show that:with the decrease of oil/water ratio, emulsion stability enhanced. Wettability experiments show that:YF can reverse the slide from lipophilic to hydrophilic and keep the hydrophily of the hydrophilic slide. Static adsorption experiments show that the maximum adsorption of YF is0.6mg/g, that is less than the screening criteria of1mg/g. The researches of the impact between HK and YF show that:with the increasing of YF, the foam volume i unaffected but foam stability reduced. When the content of YF is50%, the drainage half-life of YH foam is6.67min. With the increasing of HK, the IFT is increased. When the content of HK is50%, the IFT is1.15×10-1mN/m.Physical model experiments show that:the contribution of Jamin effect to HK foam resistance factor is44.84%, and the contribution of liquid viscosity is44.84%.The foam resistance factor, which is aged120days, is25.73%greater than the contrast sample. Flooding experiments show that foam system can improve oil recovery above20%after water flooding. And lower the IFT is, higher the recovery is. When the IFT is reduced from the degree of10"2mN/m to degree of10-3mN/m, the increased recovery is greatest. Surfactant flooding after foam flooding can give full play to their strengths, the EOR is about40%. In the anisotropic layer, with the growing of heterogeneity the profile control of foam is greater in a range of heterogeneity.