Simulating Carbon Dioxide Sequestration/ECBM Production in Coal Seams: Effects of Permeability Anisotropies and Other Coal Properties

Duane H. Smith, W. Neal Sams, Grant Bromhal, Sinisha Jikich, Turgay Ertekin

Research output: Contribution to conferencePaper

8 Scopus citations

Abstract

Coalbed methane now accounts for a significant fraction of domestic natural gas production. Injection of carbon dioxide into coal seams is a promising technology for reducing anthropogenic greenhouse gas emissions and increasing ultimate production of coalbed methane. Reservoir simulations are an inexpensive method for designing field projects and predicting optimal tradeoffs between maximum sequestration and maximum methane production. Optimum project design and operation are expected to depend on the anisotropy of the permeability along the face-cleat and buttcleat directions, the spacing between cleats, and the sorption isotherms for methane and carbon dioxide. In this work PSU-COALCOMP, a dual-porosity coalbed methane simulator, is used to model primary and secondary production of methane from coal, for a variety of coal properties and operational parameters. It is assumed that the face and butt cleats are perpendicular to each other, with horizontal wells parallel to one type of cleat and perpendicular to the other. The well pattern consists of four horizontal production wells that form a rectangle, with four shorter horizontal wells centered within the rectangle. In the limiting case of no permeability anisotropy, the central wells form a "plus" sign within the square of production wells. All wells are operated as producers of methane and water until a specified reservoir pressure is reached, after which the central wells are operated as injectors for CO2. Production of methane continues until the CO2 concentration in the produced gas is too high. The simulation results predict the optimum lengths of the injection wells along the face- and butt-cleat directions, and how these optimum lengths depend on the permeabilities in the two directions. If the cleat spacing is sufficiently small and diffusion of the gas through the pores to the cleats is sufficiently rapid, instantaneous sorption may be assumed. Otherwise, the field performance depends on the characteristic time for transport to the cleats. The pressures at which the injection wells are operated also affect the amounts of CO 2 sequestered, through the pressure and volume constants of the sorption isotherms.

Original languageEnglish (US)
Pages3227-3241
Number of pages15
DOIs
StatePublished - 2003
EventSPE Annual Technical Conference and Exhibition, Proceedings-Mile High Meeting of the Minds - Denver, CO, United States
Duration: Oct 5 2003Oct 8 2003

Other

OtherSPE Annual Technical Conference and Exhibition, Proceedings-Mile High Meeting of the Minds
CountryUnited States
CityDenver, CO
Period10/5/0310/8/03

All Science Journal Classification (ASJC) codes

  • Fuel Technology
  • Energy Engineering and Power Technology

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    Smith, D. H., Sams, W. N., Bromhal, G., Jikich, S., & Ertekin, T. (2003). Simulating Carbon Dioxide Sequestration/ECBM Production in Coal Seams: Effects of Permeability Anisotropies and Other Coal Properties. 3227-3241. Paper presented at SPE Annual Technical Conference and Exhibition, Proceedings-Mile High Meeting of the Minds, Denver, CO, United States. https://doi.org/10.2118/84423-ms