American Oil and Gas Reporter - PBIOS 2014 Official Program Guide - 165

Permian Basin Reports
Upstream

down quickly, allowing increased processing from the CO2 injector in the adjacent
pattern to the west.
Once 271-3A was returned to production, the oil rate increased from 20 to 210
bbl/d and the GOR dropped to less than
2,000 Mcf/bbl. This is consistent with the
channel being a high-conductivity, lowvolume feature. With injector 212-2 shut
in, the response was caused by CO2 injection in the adjacent pattern, which could
not reach 271-3A while it was still connected to injector 212-2 by the channel.
This type of rate rebalancing can be
done at essentially zero capital cost, even
though the channel eventually was blocked
with a conformance polymer treatment so
that 212-2 would still provide injection
support to the other producing wells in the
pattern.
In another case, disposing of excess water into the water curtain caused the
boundary wells to be overrun. There is a
constant temptation to overinject into the
water curtain because injecting CO2 into
the active project areas displaces water that
must then be sent to disposal. Capacity in
the disposal system is limited (as is storage), so the water curtain wells tend to get
overinjected. The volume of disposal was
so great that the intake pressures in the producers could not be drawn down enough
to allow the southern half of the pattern to
be processed by CO2, even with the
largest capacity ESP that could be installed
in the 51⁄2-inch casing.
Figure 6 shows 294-1, a boundary
well that was overrun. CO2 support (red arrows) could not effectively sweep toward
the curtain until curtain injection was
scaled back. Consequently, the decision
was made to shut in water injection entirely with the idea that the edge of the reservoir itself would prevent the migration of
CO2 out of the project area. Response to

Permian Basin Motto
The motto of the Permian Basin
Oil, Land & Business Men's Association, which launched the first precursor to the PBIOS, was "If you live
in the Permian Basin, you are in the
oil business whether you believe it
or not."

Midstream

Downstream

FIGURE 6
Producing Well on Boundary Overrun by Water Curtain Injection

this adjustment was immediate and long
lasting. Oil production increased from 100
to 300 bbl/d and PIP dropped by 600 psi.
The PIP and oil rate changing in lock step
indicated that the response was caused by
the rebalancing and the processing of the
southern half of the pattern.
The successful optimization of a CO2
EOR project requires intensive and continuous reservoir surveillance. By using
surveillance to monitor individual patterns,
well-by-well opportunities can be identi-

MARK A. LINROTH is the development
team manager for Kinder-Morgan Inc. He
is responsible for designing and evaluating CO2 EOR expansion areas in the
SACROC Unit. Prior to joining KinderMorgan, Linroth worked as an independent engineering consultant specializing in designing and optimizing well
completions and stimulation treatments.
He has taught various courses in fracture
treatment design, and on-site quality
control and treatment analysis. Linroth has
30 years of experience working both independently and for a major oil company. He holds a B.S. in petroleum engineering from the Colorado School of Mines.

fied to significantly improve sweep efficiency and pattern oil recoveries by pressure and rate rebalancing.
Rate and pressure data must be gathered
and analyzed continuously to identify rebalancing opportunities. However, the high processing rate that enables the rapid feedback
between cause and effect means that individual patterns will have a rather short producing life (typically less than six years),
so adjustments need to be made as soon as
the opportunities are identified.
❒

ANDREW E. RICKARD is operations engineering/project manager at
Cambrian Management Ltd. With 30
years of petroleum engineering experience, he has experience in production,
completions, operations engineering,
log analysis, well bore intervention and
remediation, wellhead compression,
gathering lines, unconventional gas,
waterfloods, CO2 floods, artificial lift,
fishing, pipe recovery and sales. Rickard
worked at Kinder Morgan, ConocoPhillips, Stanolind Operating and
Baker Hughes before joining Cambrian
Management. He holds a B.S. in petroleum engineering from the University of
Missouri at Rolla.
OCTOBER PBIOS 2014 165

American Oil and Gas Reporter - PBIOS 2014 Official Program Guide

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