This paper is an extended abstract only. The full-length paper is not available.
The Corbett Creek Project is currently the only commercial Mannville Coalbed Methane (CBM) project in Canada. Economics of Mannville CBM development can be challenging. CBM wells require an extended period of dewatering prior to initial gas production, which places a high demand on capital in the early life of the project. Continued advancement in drilling technology and operating practices are necessary to control cost and optimize production.
This presentation will briefly review the development history of the Corbett project from its inception in 2000 as a five-spot vertical pilot through to the current horizontal development scheme. Trident's evolving exploitation strategy was instrumental in reducing drilling costs and achieving economic rates. We will explain how production was influenced by well design, and discuss the operating practices Trident is currently developing to reduce its operating costs.
Over the past year, Trident's multi-lateral wells have displayed the potential to free flow, gas lifting water without the use of artificial lift systems. If perfected, operating costs could be significantly reduced by minimizing the dependence on artificial lift systems, which are expensive to replace and maintain. Trident is currently working on identifying the driving force behind its free flowing wells in an effort to make this phenomenon repeatable and significantly reduce operating cost in the field.
The Mannville formation encompasses a large area of the Central Alberta Plains and upper Mannville coals found within this sedimentary package are estimated to contain in excess of 360TCF of natural gas(1). Multiple pilot projects have been developed in both the wet and dry Mannville coal bed methane (CBM) fairways with varying success. In July 2005 Trident, along with its partner Nexen, announced commercial production from the wet Mannville CBM project at Corbett Creek, located 90 miles NW of Edmonton, Alberta. The Corbett project proved the Mannville coals in Alberta were capable of economic production.
Early development of the Corbett Creek project placed a significant demand on capital due to the requirements of producing from a wet Mannville coal. Facilities to handle large volumes of produced saline water had to be constructed well in advance of full scale development and the extended dewatering period prior to initial gas production restricted revenues from the wells. To help overcome this obstacle, Trident began to utilize horizontal drilling technologies to accelerate the dewatering period, increase gas rates and provide quicker returns. Horizontal development achieved its objective, but introduced new operational challenges. New pumping technologies had to be developed for horizontal CBM production, and operating costs increased significantly. Trident continues to develop and test new drilling and completion technologies in an effort to optimize production in the field. Over the past year, some of the horizontal wells have begun to flow freely, gas lifting the water without the continuous use of artificial lift systems. If a pattern can be identified to make this phenomenon repeatable, the potential exists to significantly reduce operating costs in the field and generate much higher returns.
