A new regional gas play has been quietly developing in northeastern British Columbia. While world attention has been focusing on the spectacular wells at Ladyfern, another area actually offers promise for greater ultimate reserves. In the Devonian Jean Marie formation, EnCana Corp. is leading the charge in what is thought to be the largest new regional gas play in western Canada. The company, recently formed from the merger of Alberta Energy and PanCanadian Petroleum, started working on its Greater Sierra project about four years ago. Historically, the gas-bearing zone was known to cover an extensive area, but it didn't test or produce at very exciting rates in many areas. The Jean Marie is underpressured and undersaturated with respect to water and therefore is highly susceptible to damage. Conventional drilling and completion techniques were for the most part unsuccessful due to formation damage caused by exposure to water in the drilling fluids. EnCana decided to apply technology to the carbonate formation in areas where a large resource was known to exist. It combined horizontal drilling with underbalanced drilling in the gas reservoir, which solved two major issues. The horizontal wells enhanced the low productivity of the reservoir by exposing significantly more of the reservoir as well as intersecting fractures, which can enhance permeability. The underbalanced drilling techniques minimized formation damage and eliminated the need for costly reservoir stimulations. The techniques successfully raised average initial per-well production rates from 500,000 cubic feet per day to 2 million per day. Gas rates of these magnitudes were of interest to the firm. EnCana also found that it could track the Jean Marie reef margin with the use of 2-D seismic, and that this reef margin extended for several hundred miles. Even better, within a few-mile area of the reef margin, portions of the limestone reservoir had been reworked and secondary porosity had been developed. Horizontal wells in these targets were eye-popping, at times testing at rates of more than 20 million cubic feet per day for short stints. When the wells are tied into a pipeline, they can produce at rates of 5 million per day. Clearly, EnCana was on to something. Today, the company has drilled about 200 wells in the play. "This year, we expect that we will be producing 150 million cubic feet per day from the play, and that it should grow to 500 million per day in the next several years," says Randy Eresman, president of onshore North America. The play has many attractive attributes. The Jean Marie is gas saturated throughout the entire area, covering more than 12,000 square miles. As a result, many of the traditional risks associated with exploration and development have been eliminated, with the primary challenge being to identify the best reservoir trends. The wells are drilled vertically to depths ranging from 1,500 to 2,200 meters, and horizontal laterals are extended about a kilometer into the formation. A typical well costs about C$2.5 million to drill, complete and tie into the pipeline. "The Jean Marie presents a long life, low-decline production base, with a reserve life at nine to 12 years," Eresman says. These wells are relatively tight with permeabilities in the order of 0.5 millidarcy and ultimate recoveries of 3- to 5 billion cubic feet per well. "It is the application of horizontal drilling and the use of 2-D seismic along the reef margin that allows us to economically exploit this huge resource. The British Columbia government also gets some of the credit by creating a better working environment, through reduced taxes and removal of some of the red tape involved in drilling these wells." Additionally, the British Columbia government is examining other initiatives to help producers in this remote area of the province, including royalty incentives and infrastructure improvements. "This is a huge play, basically running from the border of the Northwest Territories straight down to the disturbed belt of the Foothills," says Eresman. EnCana has now acquired some 3,000 square miles of land on the play, and plans to drill on the order of 100 wells per year for the next five years. "We expect that more than 2.5 trillion cubic feet of gas will ultimately be recovered from the Jean Marie."