Amoco Production Company is actively investigating the potential for recovering tertiary oil. This paper describes the evaluation process of scoping studies performed to determine the economic feasibility of CO2 flooding West Texas properties which are currently being depleted by waterflood operations. This method was applied to the evaluation of eleven Amoco operated properties in seven fields in the Permian Basin, encompassing 2300 producers and 1600 injectors. Also included in this paper are a number of technical, operational and practical concerns which have been identified during the evaluation process.

The procedure used to evaluate the feasibility of CO2 flooding a property, as described herein, is as follows:

  • 1)

    Develop a reservoir description by using a reservoir simulator to match past waterflood performance. Requisite to this process is an understanding of the performance being simulated.

  • 2)

    Predict future waterflood performance.

  • 3)

    Predict tertiary performance by employing a simulator of miscible CO2 displacement which contains the previously developed reservoir description.

  • 4)

    Generate incremental tertiary economics using predicted tertiary rates and reserves, along with estimates of necessary investments and operating costs.

This paper includes a discussion of the methods used to match past waterflood performance of entire properties. Where available, geological data was incorporated in developing reservoir descriptions. Detailed geological evaluations of the properties are in progress which are expected to contribute to and support future refinement to the performance derived reservoir descriptions. In several cases, completed geological evaluations support the reservoir descriptions generated through performance matching. Amoco has an extensive pilot program underway in West Texas which will demonstrate the validity of the prediction technique and provide data for development of improved prediction methods.

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