Flowing gas material balance – a useful tool to revise subsurface maps
Bashirul HaqDepartment of Petroleum Engineering, King Fahd University of Petroleum and Minerals, Saudi Arabia. Email: bhaq@kfupm.edu.sa; bhaq225@gmail.com
The APPEA Journal 59(1) 228-243 https://doi.org/10.1071/AJ18205
Submitted: 7 January 2019 Accepted: 26 February 2019 Published: 17 June 2019
Abstract
Subsurface geological maps are an interpretation based on limited data, yet they are the most important vehicles used to explore for undiscovered hydrocarbons and to develop proven hydrocarbon reserves. The flowing material balance (FMB) method uses flowing well head pressure, rather than shut in reservoir pressure, to estimate gas in place (GIP) and reserves at any stage of reservoir depletion. In addition, it can be applied to estimating permeability and skin of the reservoir and predicting production problems. However, application of the FMB for revising subsurface maps is not yet well understood and requires further study. The aim of this research was to develop a systematic approach to redraw subsurface maps using FMB with the aid of reservoir simulation and interpretive contouring methods. The Havlena and Odeh interpretation method was applied to identify a drive mechanism and the FMB was used to estimate GIP, which was checked against the volumetric GIP value. The pressure history match technique and interpretive contouring were applied to draw the revised maps. This step-wise technique was applied to the Titas gas field, operated by Petrobangla, and found that the Titas gas reservoir’s drive mechanism was volumetric drive. A review of the literature, including old reports and well drilling data, confirmed that there was no evidence of aquifer drive and gas water contact in the ‘A sand’ layers. Subsurface maps of sands A2, A3 and A4 were redrawn and validated using field data.
Keywords: flowing material balance, subsurface maps, simulation, and interpretive contouring method.
Bashirul Haq is currently working as an Assistant Professor in the Department of Petroleum Engineering at King Fahd University of Petroleum and Minerals in Saudi Arab and has 13 years of experience in research, teaching, consultancy and testing in reservoir and production engineering. Haq received a PhD in Petroleum Engineering from The University of Western Australia (UWA). Haq rendered consulting services to Chevron, Helix RDS, Unocal and Bangladesh Oil, Gas and Mineral Corporation (Petrobangla) and has worked at the UWA, CSIRO and Curtin University. He is a member of Engineers Australia and SPE. |
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