Registration of fluids (oil, water and gas) in reservoir rocks is one of the tasks, that researchers solve using X-ray computed microtomography (MCT). One can find many works in this area in open literature, but most of them use bulk models or coarse rocks as research objects. Such porous systems with pores and channels size of several tens or even hundreds of micrometers allow micron resolution MCT-shooting, which is sufficient for visualization of wetting and non-wetting phases. Due to the resolution lack, finely porous saturated system study is limited, though they make up a large share of oil and gas reservoirs.
Goal of current labor is to assess opportunities and to create new approaches of MCT usage for residual water determination. There was no task for direct phase visualization because of practical application absence. This decision was contributed by analysis of core samples’ capillary curves - a significant part of filter channels and pores filled with residual water have sub-micron size.
Four methods of residual water estimation were tested: excretion of water absorption spectrum (with radiopaque and without it), analysis of integral intensity absorption spectra, analysis of single-phase flow rates field (completely calculation method). Last two methods are new and they were used for rock study for the first time. Results of residual water estimation by new methods were compared with laboratory measurements. Calculation method of single-phase flow rates field analysis for limited number of core samples allowed to obtain correlations between porosity and residual water, that are close to the actual laboratory trend for entire reservoir.
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