Print this pageDevelopment, Optimization and Future Potential of a Giant Oil Field - A Case History: Weyburn Field Southeastern Saskatchewan
EDMUNDS, ANDY C., and PAUL A. MORONEY
The Weyburn field is located 130 kilometers southeast of the city of Regina, Saskatchewan, Canada. It covers an area of approximately 180 square kilometers and contains over 176,000,000 cubic meters OOIP. The field was Discovered in 1954 and fully delineated by 1960, with vertical wells drilled on a 32 hectare spacing. Unitized in 1962 and placed on waterflood in 1964 (151 inverted nine-spot patterns). A year later oil production peaked at 7500 cubic meters per day and subsequently declined until 1985. Production decline was arrested when a 157 well vertical infill program was implemented from 1985 to 1992.
Medium gravity crude is produced from the naturally fractured Midale Beds of the Mississippian aged Charles Formation. The reservoir is subdivided into an upper chalky dolostone, the Marly and a lower heterogeneous limestone, the Vuggy. Waterflood injection occurs primarily in the Vuggy zone which is more efficiently swept. It was for this reason that the vertical infill program targeted Marly zone.
The success of a six well horizontal pilot program (1991-1992) lead to a commercial scale drilling program which began in 1993. with advancements in technology, the program has evolved from 350 meters short single, overbalanced lateral wells to dual-build, underbalanced multi-lateral wells with +4000 meters of reservoir exposure. To date there are 107 horizontal wells with 180 lateral legs, current production exceeds 3600 cubic meters per day.
Future plans include improvements in underbalanced drilling, re-entry and side-tracking of existing horizontal wells, coiled tubing applications and a CO[2] miscible flood project.