Exploration and Production Technologies
Reservoir Characterization of Bridgeport and Cypress Sandstones in Lawrence Field Illinois Last Reviewed 6/21/2013

DE-NT0005664

Goal 
The goal of this project was to test the suitability of Alkaline-Surfactant-Polymer (ASP) flood technology as an enhanced oil recovery technique for increasing oil production from the two most productive reservoirs in the Lawrence Field in Lawrence County in the Illinois Basin. The ultimate objective of this project was to expand the employment of ASP flood technology from small, limited pilots in the Bridgeport and Cypress sandstones to the remainder of the Lawrence Field.

Performers
Illinois State Geological Survey (ISGS), , Champaign, IL 61820
Rex Energy Corporation, Bridgeport, IL 62417

Background 
The Lawrence Field has produced in excess of 410 million barrels of oil since 1906 utilizing both primary and secondary recovery (water flood) methods. The field currently produces with a less than two percent oil cut and, like many mature fields in the United States, is approaching its economic limit. This is despite the fact that Lawrence Field contains a significant volume of potentially recoverable oil. ASP flood technology offers some promise for the recovery of this remaining oil.

ASP flood test laboratory results have demonstrated that an estimated 130 million barrels (bbl) of oil could potentially be extracted by employing ASP flood technology in the reservoirs of the Lawrence Field. However, ASP flooding is an untested technology in the Illinois Basin. This project presented an exceptional opportunity to perform and document field testing of this unconventional recovery technique in two of Illinois’s most prolific reservoirs: the Lawrence Field-located Bridgeport and Cypress sandstones. Rex Energy has committed time, money, and materials to this effort.

Most of the unrecovered oil in the Lawrence Field is contained in Pennsylvanian Age Bridgeport sandstones and Mississippian Age Cypress sandstones. These reservoirs are highly complex and compartmentalized. Detailed reservoir characterization/simulation modeling, including the development of 3-D geologic and stochastic models of target areas in the field, was needed to identify areas with the best potential for recovery of remaining reserves. This remaining volume includes all unswept compartments and bypassed oil. The reservoir modeling was completed as a prerequisite for the design of efficient ASP flood patterns.

This four year project designed, interpreted, and analyzed the data required to conduct reservoir characterization, accounting for the geological complexities inherent to the Bridgeport and Cypress sandstones.

Impact
The primary objective of this project was to characterize the complex reservoir geology that identifies the geologic conditions that will optimize oil recovery for expansion of the ASP pilots in the Bridgeport and Cypress sandstones to other areas of Lawrence Field. It allowed evaluation of oil recovery efficiency from Bridgeport and Cypress sandstone reservoirs using ASP technology. Additionally, evaluation of similar Pennsylvanian and Chesterian reservoirs shows that it is likely that ASP flood technology can be successfully applied to similar reservoirs in the Illinois Basin as well as to other U.S. reservoirs.

Accomplishments
Data from the 25 largest Cypress fields and the 25 largest Pennsylvanian fields in Illinois have been collected and formatted into tables for the assessment of ASP flood technology in this region. The assessment of basins within the United States with potential for ASP application was completed.

Reservoir characterization of pilot areas for Bridgeport and Cypress Sandstone reservoirs has been completed. An expansion area of approximately 5.5 square miles has been established for reservoir characterization. The project team completed research that emphasized understanding the complex relationship of depositional environment and facies variation within a rapidly altering sequence stratigraphic framework and how this relates to reservoir compartmentalization and flow unit modeling. Petrographic analyses, with emphasis on the characteristics that positively and negatively affect the reservoir properties of the separate reservoir facies, have been defined. Over 800 feet of core samples from 15 separate wells have been photographed and described in the expansion area. Additional core has recently been obtained from Rex Energy that, when incorporated into the research, has enhanced the understanding of the complex stratigraphic relationships within the Bridgeport sandstone reservoirs of the expansion area.

Rex Energy Corporation introduced chemical flooding in stages, with the first flood initiated in 2010 and a second offset pilot project initiated in 2011. Rex Energy Corporation is reporting a positive response on its ASP Middagh pilot project in the Pennsylvanian Bridgeport B reservoir in the Lawrence Field. Oil response in the 15 acre flood has continued to show an increase in oil cut from 1 to 12 percent. Total pattern production increased from 16 BOPD and stabilized at a range of 65–75 BOPD in the last three months of 2011. Peak production rose to 100+ BOPD. Oil cut in the pilot increased from 1.0 to ~ 12.0 percent with individual wells showing oil cuts greater than 20 percent. A second, 58 acre pilot (Perkins-Smith) adjacent to and likely in communication with the Middagh pilot has been initiated. Preliminary brine injection has been implemented and ASP injection was initiated in mid-2012. Response is expected by mid-2013 with peak recovery expected by late 2013. Rex Energy is projecting full-scale expansion with the next step of development being a 351 acre project scheduled to begin in mid-2013.

Current Status (June 2013)
The project has been completed.

Project Start: September 22, 2008
Project End: March 21, 2013

DOE Contribution: $1,460,717
Performer Contribution: $410,664

Contact Information:
NETL – –Sinisha (Jay) Jikich (Sinisha.Jikich@netl.doe.gov or 304-285-4320
Illinois State Geological Survey - John Grube (grube@isgs.uiuc.edu or 217-244-1716)
If you are unable to reach the above personnel, please contact the content manager.

Additional Information

Final Project Report [PDF-57.3MB]

An article entitled “Illinois Basin Application Demonstrating Potential of ASP EOR Technology” was the cover story in American Oil and Gas Reporter, June 2012, pp. 83–91.

ASP Technology Increases Production from Depleted U.S. Oil Field [PDF-1.76MB] - News Release September, 2012

Beverly Seyler, John Grube, Bryan G. Huff, Curt S. Blakley, and Philip Johanek, 2009, Reservoir Characterization of the Mississippian Cypress Sandstone at Lawrence Field, Illinois, Program with abstracts 2009 Eastern Section American Association of Petroleum Geologists p. 50

John P. Grube, James Damico and Beverly Seyler, 2009, Enhanced Oil Recovery and CO2 Sequestration Potential of Chesterian (Mississippian) Sandstones in the Illinois Basin in Program with abstracts 2009 Eastern Section American Association of Petroleum Geologists p. 38


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