TIGHT GAS SPECIAL REPORT
TIGHT TIMES With trillions of cubic feet of gas tied up in low permeability reservoirs, tight gas production has become the hot topic. Schlumberger’s Lee Ramsey talks to O&G ME round the world there are trillions of cubic feet of gas that could be used to supplement the world’s energy supplies. However, much of this abundant resource is difficult to produce because the gas is held in tight reservoirs where the permeability of the reservoir rocks is extremely low. Producing tight gas is challenging, yet considering the quantities available and the long-term producability of this resource, such non-conventional gas is now being regarded as a significant energy resource for the future. Tight gas could help to address the predicted deficit between energy supplies and demand in the coming decades.
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To understand the economic viability of the complex, unconventional gas developments of tomorrow, Middle East operators must focus on new solutions today. A concerted technological effort to better understand tight gas resource characteristics and to develop solid engineering approaches is necessary to deliver significant production increases. Schlumberger has risen to the challenge, and through real collaborative efforts with Saudi Aramco and its international oil company partnerships, its Tight Gas Center of Excellence in Dhahran, is delivering bona fide leaps in reservoir understanding.
Lee Ramsey, manager of the Tight Gas Center of Excellence (TGCoE), tells Oil & Gas Middle East that the exciting developments are important steps to a real game changing approach to the tight gas conundrum.
THE BASICS The permeability of rock formations is essentially what governs how easily gas held within will flow. High permeability carbonate formations have higher porosity and often have natural fractures through which gas will easily flow, and are typically prolific producers without the need for technically sophisticated approaches. “In the Middle East people are accustomed to working with
carbonates which have a very high permeability that will produce naturally or, if the wellbore is damaged, a matrix stimulation with a little bit of acid,” explains Ramsey. “However, tight gas fields (today Schlumberger has a working definition of 0.1 millidarcy and below as tight gas), will usually not flow with a simple perforation. It requires a much deeper understanding of the reservoir and accurately tailored solutions that fit, as well as specialist treatment fluids and techniques,” he adds. “What we are advocating is that the decision of whether to use a well for production should not be made exclusively on initial flow appraisals. With improved understanding of the
Seismic field work being carried out by Saudi Aramco.
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December 2009 Oil&Gas Middle East
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