Abstract
The oil–water two-phase flow mechanism is the critical issue for producing shale oil reservoirs after huge-volume hydraulic fracturing treatment. Due to the extremely low permeability of the shale matrix, the two-phase experimental measurement is impossible for shale samples. In this work, a pore network model is proposed to simulate steady-state oil–water flow with mixed wettability under consideration. The model is first applied in Berea sandstone, and the calculated relative permeabilities are validated with experimental studies for different wettability scenarios. Then, the three-dimensional FIB-SEM imaging of the Jimsar shale sample is used to extract a representative shale pore network with 13,419 pores and 31,393 throats. The mean values of pores and throats are 29.75 and 19.13 nm, and the calculated absolute permeability is 0.005 mD. With our proposed model, the calculated relative permeability curves show a high residual oil saturation for all the wettability conditions. Specifically, the oil-wet and mixed-wet conditions yield lower residual oil compared with the water-wet condition. For 50–50 mixed-wet conditions, the water phase relative permeability is much higher for smaller pores being oil-wet than the larger pores being oil-wet.
Highlights
Worldwide, the shale oil and gas reservoirs are important supplementary unconventional resources for the petroleum industry
The model is first applied in Berea sandstone, and the calculated relative permeabilities are validated with experimental studies for different wettability scenarios
Three-dimensional focused ion beam scanning electron microscope (FIB-SEM) imaging of the Jimsar shale sample is used to extract a representative shale pore network used within our proposed model to investigate the oil–water flow mechanisms
Summary
The shale oil and gas reservoirs are important supplementary unconventional resources for the petroleum industry. The digital rock physics and pore-scale modeling methods are believed to be a substitute for laboratory multiphase flow experimental studies. The focused ion beam scanning electron microscope (FIB-SEM) imaging technique is introduced to reconstruct shale digital rock data (Kelly et al, 2016) This approach works by creating an image of the surface layer of a sample, which is stripped away using a beam of charged particles to reveal the layer beneath. As for pore-scale modeling methods, there are mainly two types: direct numerical simulation and pore network modeling The former method consists of conventional grid-based CFD methods, e.g., Oil-Water Flow in Shale. Three-dimensional FIB-SEM imaging of the Jimsar shale sample is used to extract a representative shale pore network used within our proposed model to investigate the oil–water flow mechanisms
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
