Collection of old exam papers part 2

Pagina 1

Oil & Gas Esami Reservoir Engineering, Martin J. Blunt Master of Science in Petroleum Engineering and Petroleum Geoscience, Department of Earth Science and Engineering, Imperial College London and Politecnico di Milano 324 MSc. EXAMINATION 2010 For internal students of the Imperial College of Science, Technology and Medicine Taken by students of the Department of Earth Science and Engineering This paper is also taken for the relevant examination for the Associateship of the Royal School of Mines RESERVOIR ENGINEERING I (RESERVOIR MECHANICS AND SE CONDARY RECOVERY) Answer any THREE questions 1. Material balance for a gas field (50 marks total) (i) Explain what is meant by: wet gas, a gas condensate field, primary recovery, secondary recovery, recovery factor. (10 marks) (ii) You have the following production data for a very small dry gas field that is produced by a natural water drive. Pressure G p Bg (MPa) (10 6 scf) (rb/scf) 31.0 0 0.00123 30.6 25.0 0.00137 30.2 47.4 0.00159 29.8 66.4 0.00203 The initial water saturation is 0.28 and the residual gas saturation, from laboratory measurements, is 0.32. The material balance equation is: g e g gi p B W B BGG +      −= 1 Assuming a simple aquifer model, make an approximate estimate of the original gas in place and the value of the aquifer size times the aquifer compressibility. You may neglect the compressibility of the connate water and rock in the gas field itself. Is there evidence of significant water influx? (20 marks ) (iii) What is the recovery factor now? Estimate the maximum possible recovery factor for this field based on the laboratory measurement of residual gas saturation. Comment on your answer. What further development options would you consider in this field? (20 marks) Reservoir Engineering, Martin…