Abstract:

The objective of this work was to develop a methodology to increase the productivity of gas/condensate from gas-condensate reservoirs. Presently, gas-condensate reservoirs experience reductions in productivity by as much as a factor of 10 due to the dropout of liquid close to the wellbore. The liquid dropout blocks the flow of gas to the well and lowers the overall energy output by a very substantial degree. The combination of condensate phase behavior and rock relative permeability results in a composition change of the reservoir fluid, as heavier components separate into the dropped-out liquid while the flowing gas phase becomes lighter in composition. This effect has been sparsely recognized in the literature, although there is clear evidence of it in field observations. This work quantified the effect, developed a scientific understanding of the phenomena, and used the results to investigate ways to enhance the productivity by controlling the liquid composition that drops out close to the well. By optimizing the producing pressure strategy, it should be possible to cause a lighter liquid to be condensed in the reservoir, after which the productivity loss would be more easily remedied. The research made use of experimental measurements of gas-condensate flow, as well as compositional numerical simulations. Different strategies have been compared, and the optimum producing sequences are suggested for maximum condensate recovery. Results show that composition varies significantly as a function of fluid phase behavior and producing sequence; condensate recovery can be improved with proper producing strategy, and productivity loss can be reduced by changing the producing sequence. This study can be used to determine the optimum producing strategy when the well is brought into production and reduce the productivity loss caused by the condensate banking effect.

Press the Back button in your browser.

Copyright 2009, Chunmei Shi: Please note that the reports and theses are copyright to their original authors. Authors have given written permission for their work to be made available here. Readers who download reports from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the author, Chunmei Shi.