Exploration and Production Technologies

Multidisciplinary Imaging Rock Properties in Carbonate Reservoirs for Flow Unit Targeting

DE-FC26-01BC15351

Program
This project was selected in response to DOE's Oil Exploration and Production solicitation DE-PS26-01NT41048, focus area Critical Upstream Advanced Diagnostics and Imaging Technology. The goal of the solicitation was to continue critical upstream cross-cutting, interdisciplinary research for the development of advanced and innovative technologies for imaging and quantifying reservoir rock and fluid properties for improved oil recovery.

Project Goal
The objectives of the project were to develop and test new methodologies for improved imaging, measuring, modeling, and prediction of reservoir properties in carbonate reservoirs based on an analysis of data from the Permian-age Fullerton Clear Fork reservoir in the Permian Basin of West Texas. The ultimate goal of the project was to develop new, more cost-effective ways to locate and recover the oil remaining in this and analogous carbonate reservoirs in the Permian Basin and throughout the United States.

Performers
University of Texas
Austin, TX

ExxonMobil
Houston, TX

Occidental Petroleum Corp.
Los Angeles, CA

Project Results
The major achievement of the project was the development of a detailed and comprehensive characterization of a low recovery-efficiency carbonate platform reservoir that can be used to design strategies for more-efficient recovery of the large remaining oil volume that exists in this and similar reservoirs in the Permian Basin.

Benefits
Project findings and data provide an incredibly valuable resource for encouraging new investment in older oil fields in the Permian Basin. This knowledge will decrease risk and therefore improve the economics of oil recovery in this and analogous fields. Project data sets already have elucidated numerous opportunities for drilling and recompletion in the subject field. Derivative studies also have provided an incentive for enhanced recovery activities in other reservoirs. These results already are resulting in an increase in oil production from the Permian Basin, benefiting the State of Texas and the Nation.

Background
Despite declining production rates, existing reservoirs in the United States contain large quantities of remaining oil and gas that constitute a huge target for improved diagnosis and imaging of reservoir properties. The Permian Basin alone contains as much as 30 billion barrels of remaining mobile oil. The project provides new data, models, and methods to recover the large volume of oil remaining in the subject field and many others.

Project Summary
Among the project's major achievements, researchers have:

  • Constructed a full-field (35,000 acre) reservoir model (including porosity, permeability, and saturation).
  • Performed fluid flow simulation of a 2,000-acre area to analyze flow patterns and provide basis for assessing the viability of CO2 injection.
  • Developed techniques for constructing a 3-D inversion model for improved porosity and permeability imaging.
  • Provided recommendations to the operator on new infill drilling locations.
  • Produced revised estimates of original-oil-in-place and the distribution of remaining oil.
  • Created improved images of porosity, permeability, and oil saturation.
  • Created an enhanced image of reservoir architecture.
  • Developed approaches to define permeability and saturation relationships in analogous reservoirs.
  • Delivered all data (12 gigabytes) to the operator.

Current Status(October 2005)
After completion of the project, 14 new wells were drilled in the field as a result of recommendations made during the study. Data from these wells have been added to the project data set for evaluation.

Based on results of this Fullerton study, the project team was asked by another operator to apply project results to another Clear Fork reservoir in the basin. This work is complete and now forms the basis of plans for implementing a new CO2 injection program in that field.

Publication
Final technical report, December 2004; available at http://www.beg.utexas.edu/resprog/fullerton/index.htm.

Project Start: November 1, 2001
Project End: July 31, 2004

DOE Contribution: $499,605 
Performer Contribution: $1,861,151 (79% of total)

Contact Information:
NETL - Daniel Ferguson (Daniel.ferguson@netl.doe.gov or 918-699-2047)
U. of Texas - Stephen Ruppel (Stephen.ruppel@beg.utexas.edu or 512-471-1534)

3-D seismic amplitude extractions provide excellent images of porosity distribution for selecting optimum areas for infill drilling. Areas of high negative amplitude (orange-red colors) define high porosity, whereas gray-black areas define low porosity. 3-D data show that proposed wells in the northern half of the area will encounter reservoir porosity but those in the southern half will not. Based on these data, the latter wells were not drilled.

3-D seismic inversion provides excellent control on porosity distribution where well logs are absent or of poor quality. Blind testing demonstrates predictive ability of 3-D seismic in areas where wells are absent. When one well is removed, the wireline log model (A&B) predicts too little porosity at x and too much at y. The inversion model (C&D) does a much better job of defining true porosity in both zones.

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