Kimberly B. Dollens1,
Dana C. Larson1,
Tim A. Jones1,
Terry L. Anthony1,
David A. Howell1,
Wendy G. Storbeck2
(1) Mobil E&P, U.S, Midland, TX
(2) Storbeck Consulting, Midland, TX
Abstract: The redevelopment of a mature waterflood through the application of horizontal multi-lateral drilling technology in preparation for tertiary CO2 WAG operations
Multi-lateral horizontal drilling technology has been employed since late 1996 in the mature carbonate waterflood of the Ratherford Unit, Greater Aneth Field, San Juan County, Utah, in preparation for the implementation of a C02 Water-Alternating-Gas (WAG) tertiary recovery project, planned for initiation in 2000. The program of multi-lateral re-entries of 21 existing producers and 24 existing injectors over a two-year period (late 1996 - late 1998) was comprised of 100 laterals targeting the highly-stratified layers of the Upper Desert Creek.
Miscible flooding of the low-permeability Pennsylvanian Upper Desert Creek Zone 1 has been shown by analysis of the adjacent McElmo Creek Unit to be economic only through increased vertical/areal sweep efficiencies and processing rate obtained by the application of horizontal injector-producer pairs. The results of this study were confirmed by the 1994-1995 horizontal injection well drilling program, 1996 multi-lateral production well drilling program, and the 1995 horizontal C02 pilot pattern in the adjacent McElmo Creek Unit.
This paper will review the basic geologic and engineering concepts behind the application of horizontal drilling technology within the Ratherford Unit, detail the multilateral techniques employed and process improvements made through time, and summarize the actual field results.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana