Four major operators with significant coal seam gas (CSG) holdings in Queensland, Australia identified Progressing Cavity Pumps (PCPs) as one of the preferred artificial lift technologies to deliquify coal seams and allow the adsorbed coal seam gas to be produced to surface. Each operator also acknowledged the need to accelerate their understanding of PCP technology in order to effectively overcome the unique challenges of this application. To address this need, since early 2012, these operators have met semi-annually to share reliability data on their PCP installations and the experience gained in their field operations. It was found that, through these semi-annual meetings, learnings were accelerated. Possible solutions to key challenges were identified during the meetings, trialled in the field and evaluated for success. The results were then shared with the other operators. This paper describes the process that was used to highlight challenges and identify potential solutions. It also presents examples of solutions that proved to be effective. This collaborative effort shows that challenges can be overcome in a shortened time period, if experience and operational data is shared among operators in similar applications.
Technical collaboration between operating companies is an effective and efficient tool in accelerating learnings in the oil and gas industry where the cost to research and qualify solutions to common operating challenges can quickly become prohibitive for any one company. This paper describes the collaborative process undertaken by four companies in Australia to accelerate their understanding of Progressing Cavity Pump (PCP) technology in order to overcome the unique challenges encountered in their coal seam gas operations. Three case studies are presented that highlight the effectiveness of the technical collaborative process in addressing key technical operational challenges.
Coal seam gas, also known as coal bed methane (CBM), reservoirs contain methane gas, carbon dioxide, nitrogen and water within the coal seam matrix and cleats (Figure 1). The methane gas and various other gases remain adsorbed within the coal seam by the surrounding water and overburden pressure. To extract the methane gas, the formation pressure is reduced by removing the water, through some form of artificial lift, which allows the methane gas to desorb from the coal matrix and flow through the coal fractures to the well and then to surface. Due to the reservoir, the production profile differs from those found in traditional gas reservoirs, where gas production typically starts very high and then decreases steadily over time. Figure 2 shows a typical CSG production profile where initial water production is very high and quickly declines while gas production increases over time to a maximum and then declines (Grubb 2004; Bondurant et al. 2007).
In Australia, CSG operations are primarily located in the Bowen and Surat basins situated predominantly in the eastern Australian state of Queensland (Figure 3). Arrow Energy, BG Group QGC, Origin Energy and Santos are four large companies with significant CSG operations in both the Bowen and Surat basins. Each company identified PCPs as one of the preferred artificial lift technologies for dewatering their wells (Knafl et al. 2013).
Author: Sheldon, J., Vecere, C., Knafl, M., Johnson, J. A., & Setiadi, B. W.
Publisher: SPE Artificial Lift Conference & Exhibition-North America, 6-8 October, Houston, Texas, USA
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