Research On The Yanmuxi Oilfield Chemical Profile Control Technologies And Application

The Yanmuxi Tertiary oil reservior belongs to lithic feldspar sandstone and hybrid sandstone reservior, with the porosity of 20.4% and the permeability of 228.8×10-3μm2. It is a medium porosity and medium permeability reservoir. The crude oil from the Yanmuxi Tertiary oil reservoir has the characteristic of low density, low viscosity, low gas-oil ratio, low freezing point and medium wax content. The formation water is characterized by CaCl2 type water with high salinity ranging from less than 115500 mg/L to 191800 mg/L. The Tertiary oil reservoir belongs to abnormal low temperature system, whose ground temperature is 50.3℃ and whose geothermal gradient is 2.5℃/100 m. It belongs to normal pressure system, with the formation pressure of 16.21 MPa, the saturation pressure of 2.1MPa and the pressure coefficient of 1.0. The reservoir plane contradition and the profile contradiction are both obvious.The oil well mainly has single direction breakthrough after its response and breakthough. The test results of the tracer show thatthe front advanced velocity has speeded up and the plane contradiction has sharpened in recent years. During the exploitation of the oil reservoir, polymer gels and cubical expansion particles are successively used for the profile control, but the effect is not ideal.The study starts from the reservoir. The evaluations of the reservoir lithologic, physical properties, sensitivity, famation water properties provide a geological foundation for the formulation screening of the profile control system. It makes a summary of the reasons of no effect and the flexibility of the past chemical profile control system, to choose the proper chemical profile control system of the present reservoir exploitation period. The chemical profile control of the Yanmuxi Tertiary oil reservoir in 2012 was highly effective. The chemical profile control of the Yanmuxi Tertiary oil reservoir in 2012 was highly effective, which lowered the water cut in the high water cut period, provided the technical support for improving the exploitation effect during reservoir waterflooding medium and later periods and at the same time, provided successful experience for the chemical profile control of the same type of high-salinity reservoirs.