Experimental study into the effectiveness of the partial gas cycling process in the gas-condensate reservoir development

ABSTRACT

In this study a laboratory study was carried out with the purposes of estimating the effectiveness of the gas cycling process during gas-condensate reservoir development. Specific laboratory equipment was constructed to carry out an experimental investigation by modelling the gas injection and reservoir depletion process. Volumetric properties, fog up, liquid drop-out condition, and retrograde dew point pressures of gas-condensate fluids were investigated. The reservoir fluid was recombined based on samples from Azerbaijan natural gas-condensate reservoir. Results are describing gas injection effect on condensate/gas ratio and condensate recovery in each pressure step. These have provided an understanding on the influence of the retrograde dew point pressure on optimum gas injection stage. The analyses also assure that as condensate/gas ratio decreases continually during the gas injection process, which causes the reservoir fluid PVT characteristics to be changed accordingly furthermore the reservoir pressure can be depleted in order to vaporize the liquid phase and to maintain the reservoir fluid to be in a single phase state during the reservoir exploitation. It was seen to be closely related with retrograde dew point pressure and fog up pressures. Therefore, in terms of incorporating colloidal systems into the subject focusing more on the region between fogging up and retrograde condensation gave interesting results.

KEYWORDS:

• Condensate
• dew point pressure
• gas
• gas injection
• liquid
• phase transformation
• reservoir

Acknowledgments

The authors wish to thank Professor Mr. Abbasov Z. Y. for encouragement and guidance throughout this research, PhD Mamedova G. G. and Salimova T. T. for the manufacture and maintenance of the experimental facilities and also Paul Chapman (BP Operations Support) for his review and valuable advice.

This work was implemented by the full financial support of the Azerbaijan National Academy of Sciences (ANAS) within the program “Complex of researches of theoretical and experimental interdisciplinary problems of geomechanics,” under the resolution of the Presidium of ANAS #5/3 dated on February 11, 2015.