RPSEA II Research Project: Identifying and Developing Technology for Enabling Small Producers to Pursue the Residual Oil Zone (ROZ) Fairways of the Permian Basin, San Andres (View Final Report here)
The work completed in RPSEA I allowed for the development of a methodology for collection of an exhaustive data set for one area of the Permian Basin, the north and east shelf areas of the Delaware Basin. What came to light as a result of the interactions with professionals in the Permian Basin through the course of the early ROZ studies was that many regions of the Permian Basin have very large ROZ resources. Figure 2 below represents the final RPSEA II report version of the San Andres ROZ fairways throughout the Permian Basin. The criteria for mapping the fairways was 20% residual oil saturation for a minimum 100’ thick interval. The map represents the collective work of the RPSEA I and II mapping efforts
The RPSEA II effort was, therefore, a natural extension and evolution of the RPSEA I work to examine the more regional Permian Basin expanse. In addition, the lessons on ROZ origins and distributions can be projected to other Basins around the U.S. and world and two quick studies on the Cedar Creek anticline area of the southern Williston Basin and the Big Horn Basin in Wyoming were included in the final report.
We now believe the size of the Permian Basin’s San Andres formation ROZ resource is enormous (over 180 billion barrels of oil in place (OIP). One of the problems of the findings here is that these first estimates of oil in place are so large that skeptics will be everywhere. So what is needed is a continuing vetting process of the basin-wide oil resource and more intensive outreach to the producer community. What is helping that outreach, in addition to the presentations at the annual CO2 Flooding Conference, is the serendipitous discovery that these zones can be commercially exploited by reservoir depressuring in conjunction with the new horizontal and stimulation technologies developed for the shales. A chapter in the final report is devoted to this commercial development.
The first part of the study was to collect data, logs, cuttings and water samples from various regions with the Permian Basin. The geophysical and mud log analyses were critical for identifying where ROZs exist and where they are not present and to give a qualitative indicator of gas content in the oil. The trends of the ROZs (aka fairways) were mapped and the oil in place estimated. The forecasts for CO2 EOR recovery factors from the OIP numbers (developed from the concurrent DOE project) in the ROZ were used to estimate the producible resources.
The Project Team wishes to thank the sponsors and contributing members of the research task. In addition to The University of Texas of the Permian Basin (Prime Contractor to RPSEA) and Melzer Consulting, co-principle investigator, the following companies and organizations were vital to the studies:
Advanced Resources International
Arcadis U.S.
Legado Resources, The Woodlands, Tx
Chevron, Houston & Texas Offices
ER Operating, Dallas, Texas
Timberline Oil and Gas Resources, Rapid City, SD
Tabula Rasa, Houston, Tx
Kinder Morgan CO2 Company, Houston, Tx