The Williston Basin of North Dakota is estimated to contain more than 530 billion tons of sub-bituminous and lignite coal. Calculations based upon these volumes, and gas-sorption values from nearby biogenic methane producing basins yield in-place methane gas reserve estimates of greater than 13TCF.

"Next Generation" coalbed methane plays are defined as areas where:

1. Coal-bearing units have been drilled, logged and mapped to establish with moderate scientific accuracy the areal extent of potential gas-bearing beds.
2. Coals contain sufficient favorable coal macerals for both gas storage and cleat development;
3. Coal beds are sufficiently deep to retain adsorbed gas and yet at the same time, are not too deep to be drilled economically;
4. There are primary indicators of the presence of methane gas exist such as gas "shows" from wells, mines, out houses, etc. in coal seams; coal-associated lithologies that have been extensively clinkered; coal seam and mine fires.
5. There exist favorable basinal hydrodynamic settings and histories (biogenic gas) or sediment burial histories (thermogenic gas) for gas generation;
6. Due to coal thickness, lower rank, or both, industry activity in the form of pilot studies or production has yet to take place;
7. The basic infrastructure of a natural gas delivery system is in place

Geologic analyses of the lignite deposits in the Williston Basin indicate that certain of these deposits exhibit highly favorable criteria for sourcing and containing abundant relatively shallow reserves of biogenically generated methane gas. Coal beds, which range from 20 to 100 feet in thickness and extend with good continuity for over more than 880,000 acres exhibit a vast potential reservoir for biogenic methane gas. Gas indications such as burning coal seams and mine fires, extensive clinkering on outcrop from gas-enhanced coal seam fires; and gas (methane) production from wells drilled into coals are direct indicators of methane gas in these deposits. It is worthy to note that all of these indicators are also present in the "world class" coalbed methane play of the Powder River Basin of Wyoming and Montana. Most of the coalbed methane gas reserves in the northern Rocky Mountain area including North Dakota, Montana, and Wyoming are contained in Tertiary predominantly fluvial and associated coal-bearing units that have not undergone deep burial and advanced stages of coalification. These methane reserves are considered to be predominantly biogenic in origin. The coals typically exhibit heating values from 6500 to 9500 BTU; are lower rank; high in volatiles and moisture content, but low in sulfur and ash. The similar and related geologic history and depositional setting of Williston Basin lignite coal deposits with those of the Fort Union Fm. coal beds in the Wyoming Powder River Basin is widely accepted. There are several essential factors that control biogenic gas generation and thereby also determine the methane gas generating potential of shallower lower rank coals such as those of the Powder River and Williston Basins. These are:

1. An active groundwater flow is essential to supply methanogenic bacteria into the source/reservoir system;
2. Relatively lower temperatures that allow bacterial action to take place (above the thermogenic depth window).

Such conditions have and do exist now for coals of the Williston Basin. The unique circumstance of an extremely active pale-hydrodynamic groundwater flow during the melting of the Pleistocene continental glaciers in North Dakota is proposed to have resulted in a greater than normal flushing of Williston Basin coal units by methanogenic bacteria-bearing ground waters. This abnormally high rate of flushing took place periodically over a span of between 2 million to 12,000 years ago.

Sorbed gas calculations using the Kim Relationship were made utilizing standard coal quality measurements from Proximate Analyses of samples from Williston Basin coals. Approximate sorbed gas concentrations yield values that compare favorably to producing coals from the Powder River Basin. Comparison of coal quality parameters from methane-gas producing Wyoming sub-bituminous coals and Williston Basin lignite/sub-bituminous coals, shows slightly diminished but parallel relationship that allows for a projected estimate of possible sorbed gas content. Coals in North Dakota vary from outcrop to 700' +/- in depth. Additional factors that are important in evaluating the viability of a coalbed methane prospect concern the nature of the coal itself. Some researchers maintain that an alternating stratigraphic mix of "dull" and "bright" coal macerals is critical in order to optimize both gas storage capacity (dull) and fracture (cleat) development. Lower rank coals such as Lignite A have tremendous internal surface area to store gas but are considered (probably in error) by some, not to have enough of the vitrinite maceral to contain a sufficiently developed cleat system. North Dakota coals have been sampled in the field and show both dull and bright coal lithologies as well as good cleat development.

It is proposed that the current lack of lignite coalbed methane activity is due primarily to:

1. Distraction by the other plays … Powder River Basin, San Juan Basin, Black Warrior Basin, etc. (all of higher rank and thicker coal (PRB))
2. Pre-conceived prejudice against lower rank coals because of both lack of pilot studies & lack of published data on core desorption tests
3. Lack of information concerning the relationship of coal macerals in the areas of gas storage vs. permeability

Experience in the coalbed methane play of the Powder River Basin indicates that canister tests alone are not sufficient to evaluate the gas content of lower rank coals such as the Tertiary lignites of the DJ and Williston Basins because of the "free gas" that is not evaluated during these tests.

Technologic advances and refinements in drilling practices and completion techniques continue as the industry pursues the great economic potential that exists in coalbed reservoirs. Such innovations are taking place in the areas of:

1. Horizontal and slant-drilled wells, which will increase the effective productive cross-section of exposed reservoir, fracture systems (cleats)
2. Multiple seam completions in single well bores
3. Completion in zones of less than 20’
4. Evaluation of and completion in thick laterally extensive and stratigraphically adjacent sandstone beds (sourced by adjacent coals)
5. Formation/reservoir-compatible non- damaging drilling fluid and drilling techniques
6. Artificial fracturing and fracture enhancement
7. Advances in produced water treatment, disposal, and re-injection
8. Gas treating and compression technologies
9. Local and sub-regional utilization of coal-gas resources for electrical generation
10. Local/sub-regional/regional development of gas pipeline transmission infrastructure.

The economic climate for coalbed methane development in North Dakota should be approaching a "spring time" of opportunity. Competitive factors such as:

1. There appear to be limited remaining opportunities in "first generation" plays
2. Some current producing areas are experiencing problems getting drilled wells on line and marketing gas due to storage and pipelines being at capacity;
3. The comparatively good water quality of Williston Basin coalbed waters relative to other plays
4. An increasing need within our economy and society for clean environmentally acceptable fuel resources for use in heating, power generation, automobile fuel cells, etc. on both local and regional scales.
5. Minor competition by other gas sources
6. One of the lowest production/severance tax situations in the region
7. Lack of competitive coalbed methane industry activity.

In conclusion, the coalbed methane resources of the Williston Basin have both the geologic and economic potential to provide a great new source of income for the state of North Dakota not only from the resource value itself but also from economic stimulation due to new industry development.

State government support of this industry will be key to its success in light of its "next generation" status. Of added incentive is the fact that North Dakota has one of the most favorable gas severance taxes in the United States at $.04.00 / mcf.