Engineering Visual Presentation E04: Characterisation of low-permeability coal seam gas reservoir permeability and permeability anisotropy using diagnostic fracture injection testing within a multi-well interference testing programme
Raymond L. JohnsonA
Prof Raymond Johnson Jr is currently General Manager of Technical Services at Novus Fuels and Professor of Well Engineering and Production Technology at the University of Queensland, Centre for Gas and Energy Transformation. He has 43 years’ experience, a PhD in Mining Engineering, a MSc in Petroleum Engineering, a Graduate Diploma in Information Technology and a BA in Chemistry. Prof Johnson is a Life Member of the Society of Petroleum Engineers (SPE), past Queensland SPE Section Chair, twice Co-Chair of the SPE Unconventional Reservoir Conference Asia Pacific, 2019 Co-Chair and 2021 Advisor of the Unconventional Resources Technology Asia Pacific Conference, three times SPE Regional Technical Award Recipient (Production Operations, Management and Information and Completion Optimisation) and the 2023 SPE Regional Service Award Recipient. Ray has served in a number of numerous technical and management positions in service, operating and consulting companies in the United States and Australia. |
Abstract
Engineering Visual Presentation E04
Low-permeability coal seam gas (CSG) reservoirs are a significant worldwide, unconventional resource for the future. In low-permeability coals, a diagnostic fracture injection test (DFIT) has been identified as the most applicable method to characterise low-permeability CSG reservoir permeability based on the inherent limitations of conventional transient testing methods. Further, determining permeability anisotropy can assist development in spacing wells or evaluate completion technologies, such as fracture stimulation, horizontal wells and multistage hydraulic fracturing from horizontal wells. This paper uses representative interburden and coal reservoir properties from a Bowen Basin case to properly define an area and develop a working hydraulic fracturing model. This model can generate a series of fracture realisations, varying bulk permeability and pressure-dependent leak-off (PDL) values to provide scenarios for later multi-well interference test analyses. Previous studies have noted that a pressure-dependent permeability (PDP) capable reservoir simulator can be used to model and history-match the after-closure period and better constrain the reservoir model for forecasting PDP effects. Finally, a multi-well DFIT/interference test programme can be evaluated using techniques to back analyse the bulk permeability and anisotropy and establish the optimal well spacing between the DFIT and observation wells. This paper presents a holistic workflow and guidelines for implementing multi-well DFIT/interference testing for low-permeability CSG fields. It can also be applied to higher-permeability coals where compartmentalisation or permeability anisotropy is not aligned with the current, localised stress regime.
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Keywords: CBM, coal seam gas, coalbed methane, CSG, DFIT, diagnostic fracture injection test, interference testing, well test analysis.
Prof Raymond Johnson Jr is currently General Manager of Technical Services at Novus Fuels and Professor of Well Engineering and Production Technology at the University of Queensland, Centre for Gas and Energy Transformation. He has 43 years’ experience, a PhD in Mining Engineering, a MSc in Petroleum Engineering, a Graduate Diploma in Information Technology and a BA in Chemistry. Prof Johnson is a Life Member of the Society of Petroleum Engineers (SPE), past Queensland SPE Section Chair, twice Co-Chair of the SPE Unconventional Reservoir Conference Asia Pacific, 2019 Co-Chair and 2021 Advisor of the Unconventional Resources Technology Asia Pacific Conference, three times SPE Regional Technical Award Recipient (Production Operations, Management and Information and Completion Optimisation) and the 2023 SPE Regional Service Award Recipient. Ray has served in a number of numerous technical and management positions in service, operating and consulting companies in the United States and Australia. |
