Coalbed and Shale Natural Gas Evaluation

Shale and coalbed gas reservoir testing and evaluation.

Intertek performs Total Quality Assurance natural gas composition and isotope measurements. Gas produced from coal bed methane and shale is ordinarily composed of several gas species in addition to methane. Correct analysis of the gas composition is necessary for proper economic evaluation of the resource being produced. Isotopic composition of the produced gas can give an idea of the natural gas’ origin, reservoir continuity and compartmentalization, migration and biogenic fraction. 

Intertek offers adsorption isotherm analysis which measures the total amount of gas that coal or shale can absorb to evaluate the saturation level of the reservoir. Isotherms are performed at reservoir temperature and at increments up to 5000 psi.

A requirement for exploiting unconventional gas reservoirs is the determination of gas in place. The field data is acquired through field desorption measurements. Intertek's wellsite desorption service utilizes well recognized and documented methods of analysis including the use of thermally regulated desorption canisters for assessing gas content of whole core, sidewall core or cuttings.

Studies show that gas desorption is critically temperature dependent; tests and measurements throughout the core analysis program are performed at reservoir temperature while ambient pressure is carefully monitored.

Unconventional natural gas includes a range of sources. These include coalbed methane and natural gas containing shales. Coalbed methane is natural gas produced from coalbeds in the same way that methane is produced from other strata. Shale gas is produced from reservoirs composed of shale. Gas shales are often source rocks and the reservoir source for natural gas. The methane can be adsorbed onto insoluble organic matter (kerogen), trapped in pore spaces of sediments interbedded with the shale, or confined in fractures in the shale. 

• Shale Oil and Gas Services