This project demonstrates the application of Advanced Secondary Recovery (ASR) technologies to remedy producibility problems at the North Robertson (Clearfork) Unit, in Gaines County, Texas. The North Robertson (Clearfork) Unit is a Shallow Shelf Carbonate (SSC) reservoir of Permian-Leonardian age operated by Fina Oil and Chemical Company. The Department of Energy (DOE) has selected the Unit as a Mid-Term Field Demonstration under the DOE Class II Oil Program.
Important producibility problems exhibited at the North Robertson (Clearfork) Unit include:Poor sweep efficiency due to a large, low permeability reservoir interval that is heterogeneous and compartmentalized, which results in poor vertical and lateral continuity of reservoir flow units.Poor balancing of injection and production rates in certain areas of the reservoir which indicates poor pressure and fluid communication and limited repressuring—possibly remedied by improved injection and production scheduling as well as injection and production well pattern re-alignments.Both injection and production wells are not optimally completed with regard to placement of perforations and the stimulation treatment is inadequate for optimal production and injection practices.
Reservoir Management Study Areas
To characterize the reservoir in terms of petrophysical properties and well deliverabilities (production potential), three different areas for focused study at the North Robertson Unit have been identified. These areas are known as Pre-Demonstration Reservoir Management Study Areas or PDSAs and were established based on varying performances of historical oil production, from excellent to poor. These areas will serve as intense areas of study, with testing optimization, simulation and forecasting, and surveillance activities during the project.
Advanced Recovery Technologies
The Advanced Secondary Recovery technologies to be demonstrated at the North Robertson (Clearfork) Unit include:Development of an integrated reservoir description created using reservoir characterization and reservoir management activities—and integration and modelling of the data from these activities using geostatistical interpretations (realizations), 3-dimensional reservoir simulation, and analytical solution methods.
Acquisition and analysis of geological data: core and well log data.