What a Horizontal Well Type Curve is Actually Telling Us

“Recovered liners were found to be almost completely covered with organic (asphaltenes) and formation material. This supplied physical evidence confirming that fines invasion of the gravel pack coupled with organic deposition severely reduced gravel pack permeability and effectively plugged the liner slots.”

SPE 35744. Increasing Hydrocarbon Production Through Liner Zone, Elk Hills Field, California
Michael G. Drown, SPE, and Juan Chacon, Bechtel Petroleum Operations, Inc., and Michael S. Stratton, SPE, Baker Hughes Inteq
Copyright 1996, Society of Petroleum Engineers, Inc
A paper prepared for presentation at the Western Reginal Meeting held in Anchorage, Alaska, 22 – 24 May 1996

Production graphs from StackDX. Type Curves super-imposed by D. Cadrin

Western Canadian horizontal well production decline matches the results of the API RP 13B-1 static drilling mud filtration test that evaluates filtercake build up vs volume of filtrate passing through a filter at constant pressure exposing bituminous filtercake build up around the slotted liner as the cause of the profound failure to translate accessed reservoir into produced reserves rather than pressure depletion.

Unconsolidated sand reservoir is a 70% slurry of sand/silt/clay and fines suspended in viscous oil.

CHOPS well completions produce the near wellbore slurry that slotted liners are designed to separate into filtercake and oil.

A completion that makes it impossible for filtercake to form plus the creation of a near wellbore sand-free cavity has stimulated rate and recovery beyond what flow theory predicts in thousands of vertical wells in Western Canada.

Although the CHOPS multiplier effect is well known in Western Canada it has not been recognized as an option in horizontal heavy oil wells.

Horizontal wells with slotted liners have produced only the portion of accessable oil that was able to make its way through progressively constricting near-liner permeability .