Study On The Formulation Of Surfactant/Polymer Combined Flooding In The Offshore Oilfield

Laboratory studies and field tests show that the ASP flooding is an effective method to enhance the oil recovery, however, the negative problems (scale formation&viscosity reduction etc.)of ASP flooding caused by the addition of alkaline scale, limit the implementation of ASP flooding in the high salinity reservoir. In this paper, the binary compound flooding is studied for LD 10-1 offshore oilfield with high content of calcium and magnesium ions and serious heterogeneity. First, the polymer and surfactant used for binary compound flooding were screened, which formed a series of binary compound flooding formulations, which have different viscosity and interfacial tention, the result shows that:the compound systerms composed of Polyacrylamide polymer,petroleum sulfonate KPS (Xin Jiang) and YG210-10 have good compatibility, aging stability, shear resistance.The optimal formulation is obtained by physical simulation flooding experiments, the optimal formulation can enhance oil recoyvery greatly without ultra-low interfacial tension, and the definitions of the critical viscosity and optimal interfacial tention are given for the particular heterogeneous reservoir (critical viscosity 15mPa·s,the optimal interfacial tension is 1.865×10-2mN/m). Microscopic visualization of flooding experiment showed that: the emulsion consisted of the binary compound systerm and LD10-1 crude oil has good stability, the emulsion droplet of the optimal formulation can block the high permeability layer by Jamin effect, thus increasing conformance efficiency of the compound system and enhancing oil recovery, which provides a theoretical basis for chemical flooding and have a certain significance for the field test.