unconventional gas sources tight gas cbm gas shales

• Unconventional Gas Sources• Tight Gas • CBM• Gas Shales

US Has 211 tcf proved reserves1,750 tcf technically recoverable60% on shore reserves are unconvetionalConsumes 23 tcf/dayProduces 20 tcf/day

Gas Production

Gas Usage

• Shale Gas• Wells produce from low perm shale

formations that are also the source for the natural gas. Gas stored in the porosity and macro porosity and can be adsorbed onto the minerals or organic matter in the shale

• Tight Gas• Wells produce from low porosity low

permeability sandstones or carbonites.

– Unconvental Gas– Tight gas – Low Perm– CBM – 10% of present production– Gas Shales – 10% of present production

Background of Shale GasThe first well drilled in 1821, Fredonia, NYSome work in Ohio area pre WWIIFirst real big play Barnett in North Texas

Big Frac jobs 1987Horizontal well 1992Combined with stages frac jobs 1998

Gas Shales vs Tight GasThe main difference is that the oil and gas shales are the source rock for the hydrocarbons. In tight reservoirs the gas migrates from the shale to the production formation, in the gas shales the shale formationis so tight that the gas or oil cannot or is limited in migrating out. The gas is stored in the porosity of both types of reservoirs.

Factors in making a good gas shale field

Total Organic Content TOCThermal MaturityFracture networkQuartz and clay %Formation BrittlenessPressure gradient ThicknessPorosity

Thermal Maturity The breakdown of the organic material Kerogen (pre oil gas) The more mature the better Vitrinite Reflectance Carbon isotopes 13C to 12C

Many reservoirs will have different areas of maturityshown by wet and dry areas

Eagle Ford

Characteristics of a reservoirBarnett

7500 ftPressure 4000 psiTemperature 200 FPorosity 6%Perm 250 nDAdsorbed gas 35%Pressure gradient .526 psi/ft

What works in Oil and Gas Shales

Some fields have been developed with Vertical wells with large frac jobs

Most today are developed with Horizontal wells with multi staged frac jobs

Some of the frac jobs can exceed 4,000,000 gallons

To quiet drilling operations