American Institute of Mining, Metallurgical and Petroleum Engineers, Inc.
This paper was prepared for the Society of Petroleum Engineers of AIME, Regional Secondary Recovery Symposium, to be held in Pampa, Tex., Oct. 26–27, 1967. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copies. The abstract should contain conspicuous acknowledgement of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.
In July, 1963, a five-spot pilot water-flood was initiated in the Brown Dolomite of Skelly Oil Company's Schafer Ranch lease in the Panhandle Field, Carson County, Texas.
Two years later response had not yet occurred even though 1,300,000 barrels of water had been injected. Injectivity surveys indicated that the water was entering the producing formation at the well bore but what happened to it after that remained a mystery.
A decision was made to find out if the water was actually staying in the formation. This was to be done by drilling a test well half way between one of the four injection wells and the center production well.
Analysis of test data indicated that the advance portion of the flood front had already passed this position and must be close to the center producing well. The flood was behaving admirably - water was going into the formation and not channeling. Fracture treatment of the center producing well resulted in the long-awaited response.
This paper is about an evaluation of a pilot waterflood. However, it is not a theoretical evaluation based on hypothetical data. It is based on actually drilling a well in the middle of a pilot, coring, logging and testing it, and then analyzing this data. We did what many of us that try to deal in abstract reservoir engineering would love to do. In effect, we went down and took a chunk out of the reservoir while it was in the process of being flooded.
The pilot (Figure 1) is located in the Texas Panhandle Field: the second largest field in terms of cumulative production in the United States. Only the East Texas Field is larger, with a cumulative production of 3.7 billion barrels compared to the Panhandle Field's 1.2 billion barrels. This field is over 100 miles long and extends into five counties. Just to the south of the field is a buried granite mountain ridge, called the Amarillo Mountains, which extends into Oklahoma where it becomes the Wichita Mountains.
