GRUMMON, MARK, Coastal Oil & Gas Corporation, Denver, CO

ABSTRACT: Exploiting the Self-Sourcing Cane Creek Zone of the Paradox Formation with Horizontal Wells

The Cane Creek zone of the Paradox Formation produces oil and gas from fracture-induced permeability and porosity in the Big Flat/Lisbon area of the Paradox basin. Only one of approximately 110 vertical wildcats has been a commercial Cane Creek success, having recovered more than 900,000 bbl oil. Horizontal

drilling significantly improves wildcat success rate by increasing well-bore contact with near-vertical fractures. Six horizontal Cane Creek wells resulted in three discoveries, each with initial flow rates in excess of 1000 BOPD and potential reserves in excess of 500,000 bbl of oil per well.

The Cane Creek Shale is the thickest and most productive of the 29 clastic intervals in the Paradox Formation. The reservoir is self-sourced from interbedded black sapropellic dolomites with up to 28% total organic carbon. Micro- and macrofractures, along with some matrix porosity, contribute to reservoir storage capacity, although the relative importance of each remains undetermined. Matrix permeability is very low. Overlying and underlying salt beds provide very effective seals.

Well-bore communication with a network of natural fractures is essential to establishing commercial hydrocarbon production. Silty and sandy carbonates are the most fracture-prone lithofacies. The middle silty carbonate zone of the Cane Creek is the primary target for horizontal drilling because of the relative thickness of fracture-prone lithologies, the absence of interbedded anhydrites, and the presence of the best source-rock facies.

AAPG Search and Discovery Article #90993©1993 AAPG Rocky Mountain Section Meeting, Salt Lake City, Utah, September 12-15, 1993.