Abstract

We have developed and applied a workflow for the initial exploration of source rock potential as unconventional reservoirs utilizing pre-existing limited data sets. The method uses a multi-disciplinary work-scope in several phases allowing for a broad evaluation of the key success factors for a source rock in a selected project area. The methodology is designed to establish an initial baseline of understanding of key production drivers such as charge, maturity, reservoir quality, completion quality, structure, geomechanic properties and fluids.

The baseline is achieved by integrating core, log and seismic data in an initial 3D depth model that can be utilized for calibrating a petroleum system evaluation leading to the generation of play fairway maps and an initial resource in place estimate. A further phase provides an economic viability assessment and cost expectations for exploitation of the unconventional source rock. The method provides the necessary support for key decisions including planning of pilot well locations, and an associated data acquisition strategy including core collection, logging programs and optimization of future seismic programs. By combining information from the play fairway mapping with representative petroleum engineering estimates it is possible to provide probabilistic estimates of economically recoverable resource volumes in each assessment unit and use this analysis to establish whether there is an opportunity for economically viable production within the study area.

A strong emphasis is placed on rapidly integrating the available existing data in order to support the decision making process. From a number of examples around the world we have seen data quality and quantity vary tremendously and have adapted the workflow and scope for each project accordingly. The type of data commonly retrieved and utilized includes 2D seismic data, occasionally 3D conventional narrow azimuth seismic surveys, and vintage log suites for petrophysical calibration, occasionally core data, temperature gradients, organic information and literature from basin characterization studies.

A number of these studies have been conducted or are in progress. However the authors will focus on the results of a study in North Africa to demonstrate the value of the methodology in rapidly and positively impacting the decision making process.

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