Experiments of Water Flooded Longitudinal State on Offshore Thick Reservoir

Abstract

Reservoir sedimentary rhythmic is an important geological factors influencing the dynamic characteristics of the reservoir development and residual oil distribution. Bohai LD oil field is a typical thick reservoir, large well spacing multilayer commingled production in offshore oil field conditions, the gravity effect is more apparent, the remaining oil in the middle and high water period is comparatively complicated. For further study the remaining oil distribution of reservoir after water flooding, the research of indoor core displacement experiment was carried out. Combine the reservoir properties, design parameters according to similar principle, in this paper, the distribution of remaining oil and the production dynamics characteristics under different rhythm is researched. The research results indicate that: Due to gravitational differentiation, the reservoir is submerged at the bottom under homogeneous rhythm. The higher the core permeability, the stronger the gravity differentiation act, the smaller water flooded vertical thickness is, and remaining oil concentrate at the top. Gravity makes positive rhythm formation longitudinal contradictions become more prominent, after water flooding breakthrough, water cut rise fast, core recovery is low, the remaining oil is concentrated in the upper part of the low permeable formation; Gravitational differentiation can play a role in reverse rhythm, water drive is relatively uniform, core recovery is high. Under composite rhythm, the displacement situation of water drive is similar to the single rhythm.