This paper presents an analytical model for three-phase flow towards a horizontal well with multi-stage hydraulic fractures, producing from a low-permeability oil reservoir (e.g. shale oil) under primary depletion. The model accounts for time-dependent trilinear-flow model (Brown et al. 2011) and solution-gas drive model (Muskat 1981). While there are numerous analytical models proposed for inflow of horizontal wells with multistage fractures, they do not consider three-phase flow condition and/or time dependent behavior (i.e. they assume steady or pseudo-steady state conditions). These two conditions should be honored for low-permeability oil reservoirs with prolonged transient period which produce oil, water and dissolved gas. In this paper, we first present the mathematical framework for the transient three-phase trilinear flow towards a multi-fractured horizontal well in a bounded oil reservoir. Later, we combine the flow equations with the material balance equations to account for pressure depletion and solution-gas drive during primary production. We compare the predictions of our analytical model with a commercial numerical simulator. We demonstrate very good agreements of these two different approaches. Last, the advantages and limitations of this new method are discussed. Production forecast using the presented analytical model is significantly faster in comparison to the numerical simulator. This finds applications where multiple realizations are required, either during the optimal design of key factors (i.e. number of stages, spacing, optimal fracture conductivity) or during the characterization of hydraulic fractures by matching the production history.
In order to estimate the potential incremental hydrocarbon recovery by CO2 injection, compositional reservoir simulators are commonly used in the industry. Successful design and implementation of CO2 injection processes rely in part on the accuracy by which the available simulation tools can represent the physics that govern the displacement behavior in a reservoir. In this paper, we investigate the accuracy of some physical models that are frequently used to describe dispersive mixing and mass transfer in compositional reservoir simulation. We have designed a quaternary analog fluid system (alcohol-water-hydrocarbon) that mimics the phase behavior of CO2- hydrocarbon mixtures at high pressure and temperature. A porous medium was designed using PolyTetraFlouroEthylene (PTFE) materials to ensure that the analog oil acts as the wetting phase, and the properties of the porous medium were characterized in terms of porosity, permeability and dispersivity. Relative permeability and interfacial tension (IFT) measurements were also performed to delineate interactions between the fluid system and the porous medium. The effluent concentrations from 2-component first-contact miscible displacement experiments exhibit a tailing behavior that is attributed to imperfect sweep of the porous medium: a feature that is not captured by normal dispersion models. To represent this behavior in displacement calculations, we use a dual-porosity model including mass transfer between flowing and stagnant porosities. Two 4-component two-phase displacement experiments were performed at multicontact miscible conditions and the effluent concentrations were interpreted by numerical calculations. We demonstrate that the accuracy of our displacement calculations relative to the experimental observations is sensitive to the selected models for dispersive mixing, mass transfer between flowing and stagnant porosities, and IFT scaling of relative permeability functions. We also demonstrate that numerical calculations substantially agree with the experimental observations for some physical models with limited need for model parameter adjustment. The work presented in this paper is directly applicable to the study and design of EOR/sequestration processes through an improved understanding of dispersive mixing and mass transfer in these processes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.