The goal of this project was to develop and demonstrate a methodology for improved detection of natural fracture sweet spots in the Canyon Largo unit of the San Juan basin, New Mexico.
Burlington Resources, Inc. (lease owner)
Huntington Energy L.L.C. (well drilling)
Midland, TX 79702
As new discoveries from conventional supplies decline, future supplies of natural gas will have to come increasingly from low permeability (tight) reservoirs. The National Petroleum Council’s (NPC) 1992 natural gas study estimated 349 Tcf of gas resource in tight formations in major basins throughout the United States.
Areas containing significant resources/reserves include the Greater Green River, Piceance, Wind River, Uinta, San Juan and Anadarko Basins. Under current limitations in exploration and production technology, only a small portion of this vast resource can be economically developed at current gas prices. According to the 1992 NPC study, technology must continue to evolve for natural gas to fulfill its role in the United States’ energy picture.
This particular project developed a methodology for detecting gas-filled fracture sweet spots in the Dakota sandstone of the San Juan Basin, by mapping and comparing seismic attributes, petrophysical data, and available production history information. Multiple wells were drilled and tested in the Canyon Largo unit of the San Juan basin to validate the success of the method.
The San Juan Basin is the second largest gas field in the conterminous United States, with an estimated 50.6 trillion cubic feet of undiscovered natural gas, according to the U.S. Geological Survey. Nearly all of the non-coalbed gas in the basin has come from naturally-fractured tight sandstones, including those of the Dakota Group. The location, extent, and geometry of the fractures in these reservoirs have been poorly understood in the past, but studies such as this one have improved fracture prediction and fracture quantification.
Future applications of Geospectrum’s fracture prediction methodology may improve the likelihood of finding good gas wells in other parts of the San Juan basin, and in other tight sandstone plays in the greater Rocky Mountain region. Ultimately, the successful application of this methodology should significantly increase gas reserves in the San Juan basin and elsewhere by bringing more high-end producing wells on line.
Geospectrum successfully developed a fracture prediction methodology and presented results to DOE and Burlington. Burlington sited the Canyon Largo Unit #452 based on the Geospectrum’s efforts.
In December 2003, Huntington Energy drilled, logged, and cased the Canyon Largo Unit #452 well to a depth of 7,590 feet. Two Lower Dakota sandstones were perforated—the Burro Canyon (7,518-7,524 feet) and the Encinal (7,420-7,455 feet)—and both intervals had gas shows. The decision was made to produce from the shallower Encinal unit because of potential water problems below the Burro Canyon reservoir. The Encinal was isolated and fracture stimulated on January 14, 2004 and it produced gas at an initial rate of 4 mMcf per day.
In 2004,3 additional wells were drilled and completed in the Canyon Largo unit. Two of these were drilled at locations recommended by Geospectrum, using their seismic methodology for predicting fracture-related sweet spots in Dakota sandstone reservoirs. The wells drilled at sites with favorable seismic attributes came on line with very strong initial production rates, ranging from 2000-4000 MCFPD, and those wells continue to be good producers.
and Remaining Tasks:
Data from the 4 test wells were analyzed and incorporated into a final report on the fracture detection methodology and results of test wells. The final report entitled “New 3-D Seismic interpretation methods for exploration and development of fractured tight-gas reservoirs” has been completed and is listed below under "Additional Information".
Final Report [PDF-10.88MB]