Study On The Geological Modeling And The Distribution Of Residual Oil In The Late Development Period

Reservoir geology modeling, a high and new technique, has been developed during recent years, which is the most effective way to characterize the reservoir quantitatively and to portray the heterogeneity of different sizes.On the basis of complex of different subject, such as geology, sedimentology, tectonic geology, geophysics, logging,reservoir bed research, reservoir physics, fluid mechanics in porous medium, a series of research works are conducted in Wangxuzhuang biolithite reservoir Dagang, include the reservoir framework, sedimentary microfacies, biolithite reservoir model, the feature of fractures, the distribution of the fractures, in the process of research, the computer technology, numerical simulation technology and the latest laboratory simulation technology are also involed. The research indicate that the extensive distribution of the residual oil resulted by the waterflood fingering is due to the macro and microscopic heterogeneity resulted by the fracture, the unique pore type and pore distribution of biolithite.In this paper, the water displacing oil experiment in lab is first conduced on full analog simulator, in which the simulation oil and simulation water made by ourselves are used, through the test, the micro-photomicrographs of the residual oil distribution for the biolithite reservoir at the high watercut stage are obtained and the five types of microscopic distribution mode for residual oil are first concluded. On the basis of analysis for microscopic distribution mechanism of residual oil, For the purpose of improving oil recovery , a series of simulation waterflooding test have been conducted, include: profile control agent flooding, water with 2.5% Ethanol content flooding, 0.2% surfactant flooding. At the same time, we also conducted the test for changing water injection technology. According to the research result and the macro distribution law of residual oil from reservoir numerical simulation, the adjusting plan is proposed, which focused on (1) change the water injection direction and the distribution of the pressure field, (2) drilling infiller, (3) high watercut well plugging, (4) profile control. Up to date, the adjusting plan is being taken into practice, and has made good effect.