Stochastic modeling of non‐equilibrium multiphase flow in porous media

Current simulators make assumptions that may be inappropriate for modeling shale gas reservoirs. These assumptions are: 1) that the system exhibits instantaneous capillary equilibrium, 2) that transport can be completely defined by viscous flow (Darcy's law), and 3) that relative permeability is not flow rate dependant. To investigate these assumptions, a one-dimensional reservoir simulator was developed. This was then modified to implement a solution that does not force instantaneous capillary equilibrium and the effects of this phenomenon were studied. In this paper, the requirements for a realistic shale gas simulator are first reviewed and results from a model study of a shale gas reservoir using a commercial simulator are briefly discussed. A simple example illustrates why instantaneous capillary equilibrium may be inappropriate and therefore justifies the need to develop simulators that do not make the above assumptions. The mathematical formulation used to implement a non-equilibrium capillarity model is developed and discussed. Lastly, a set of simulation studies are discussed where saturation profiles for two-phase flow displacement are compared for capillary equilibrium and non-equilibrium conditions. We also investigate the effect of wettability by considering a 100% water-wet and a 100% oil-wet formation. The results indicate a dramatic impact on the saturation profiles produced by relaxing the capillary equilibrium requirement.

show abstract

Accurate Simulation of Shale-Gas Reservoirs

Perdomo

Civan

Devegowda

et al. 2010

SPE Annual Technical Conference and Exhibition

View full text Add to dashboard Cite

show abstract

Design and Examination of Requirements for a Rigorous Shale-Gas Reservoir Simulator Compared to Current Shale-Gas Simulators

Perdomo

Civan

Devegowda

et al. 2011

North American Unconventional Gas Conference and Exhibition

View full text Add to dashboard Cite

The development of shale plays in North America has achieved great success in satisfying increased energy demand. With the advances in experimental approaches, investigation of microstructures in organic-rich shale has identified several different pore types and the abundance of pores from the nanometer to the micron scale. Yet current modeling work for such reservoirs is mainly performed with dual porosity models based on Darcy's law. In addition, a great discrepancy between simulation results and production data persists. Because flow regimes in porous media are quite sensitive to pore size, the flow mechanisms in shale reservoirs are considerably more complex than Darcy flow and the feasibility of conventional models has been frequently challenged. This work presents an integration of realistic multi-porosity and multi-mechanistic treatments to resolve the conundrum of fluid flow in shale.Based on a unique reservoir simulator, a micro-scale multiple-porosity model for gas flow in shale reservoirs is presented in this paper. The model consists of three separate porosity systems: kerogen, inorganic minerals, and natural fractures. Inorganic and organic portions of the shale matrix are represented by sub-continua with different characteristics considering pore structures, fluid storage and flow mechanisms. In the kerogen gas desorption, diffusion and Darcy flow occur simultaneously. Through considering the different pore families in the kerogen, the effects of nanopores and microporosity are incorporated into the model. In addition, a novel gridding scheme has been specially designed to recognize the complex structures. To accomplish this, the grid incorporates randomly distributed kerogen in the shale matrix and different continua are tied to each other via arbitrary connectivities. Through changing the properties of both matrix and fracture, a unified concept of dynamic apparent permeability of shale matrix is proposed. The derived concept allows the design and function of the Micro-Scale Model to be extended to the reservoir scale model containing hydraulic fractures. The more realistic gas production forecasts using the workflow presented in this paper indicate significant differences from that of conventional models. The ability to more accurately simulate the complex flow mechanisms using the proposed techniques will allow operators to better predict and enhance ultimate recovery from shale reservoirs.

show abstract

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.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Stochastic modeling of non‐equilibrium multiphase flow in porous media

Cited by 2 publications

References 2 publications

Accurate Simulation of Shale-Gas Reservoirs

Accurate Simulation of Shale-Gas Reservoirs

Design and Examination of Requirements for a Rigorous Shale-Gas Reservoir Simulator Compared to Current Shale-Gas Simulators

Contact Info

Product

Resources

About