To provide a sufficient and stable supply of natural gas, producers seeking to increase reserves and governments striving to be more energy independent are exploring unconventional gas sources. To date, most unconventional gas recovery has occurred in the United States close to high energy-use areas; however, rapidly developing countries or countries that do not have easily recoverable hydrocarbons are evaluating these unconventional gas resources to help facilitate economic growth. Producers are now considering gas reserves not previously considered reservoir quality'lowpermeability sandstone, carbonates, shales, and coal seams. Case histories presented in this paper illustrate various new technologies used in exploiting commercial, gas-bearing intervals in resource plays. The discussion examines integrated technologies that can be applied either offshore or on land to produce difficult resources. The combined benefits and drivers of the technologies include:
Increased production.
Operational simplicity.
Lower recovery cost.
Increased gas deliverability relative to high energy use areas.
In dealing with gas in unconventional reservoirs, a holistic technological approach should be taken throughout the exploration/development cycle.
Within the individual well, best practices and lessons learned should be taken from the initial reservoir exposure to drilling/completion, production, and renewal activities. Renewal activities defined as re-stimulation in resource plays can provide significant recovery upside. Continuous information feedback and application of lessons learned is needed to enable better decision-making in the quest to recover unconventional gas reserves.
