Using recent advances in logging technology, it is now possible to make an in-situ characterization of gas bearing sandstone reservoirs for use in optimization of the entire completion process. Dynamic reservoir information, obtained with a wireline formation tester, and continuous high-resolution porosity and permeability data, recorded using a nuclear magnetic resonance (NMR) logging tool, provide a step-change improvement in identification of productive zones. Use of this technique can result in greatly reduced operating costs because the effective completion of these low-permeability shaly formations typically requires time-consuming rigless operations.
In this paper we show how an exhaustive openhole evaluation of reservoir quality and the gas producibility index are combined as input to a completion strategy that reduces the time between spud-in and first commercial production. This integrated approach, entailing several stages, was used to optimize the hydraulic fracturing jobs for each producing interval, thereby enhancing overall gas production. The simulated performance for each interval and prediction of flow rates were used for recommendations on completion strategies. In that sense, we will first describe how this methodology, that combines wireline "in-situ" reservoir measurements, was applied on the completion design of several key wells and finally, we will present and discuss the case-history results obtained to-date.