American Oil and Gas Reporter - December 2016 - 54

SpecialReport: Well Stimulation & Completion Technology
FIGURE 3
2-D Line From 3-D Production Attribute with Example Input Attributes
(90-day Cumulative Oil and 7,500-foot Completion Interval)
Vertical Well Calibration

Fluid/Stress

Fracturing

Brittleness

Lithology

30k

60k

Storage
90-day Oil Cumulative (BO)

3-D Production Attribute
Once a mathematical relationship is
derived from the multivariate statistics to
cumulative oil production, it can be
applied to the 3-D attributes highlighted
in the modeling workflow to develop a
regionally extensive 3-D "production attribute." This, in turn, provides a pragmatic
tool to define the highest-potential productive zones, both vertically and spatially
in a predictive sense.
Figure 3 shows a 2-D line taken from
the 3-D production attribute with example
input attributes. Color bar scaling
approximates 90-day cumulative oil
relative to a 7,500-foot completion interval
on a horizontal wellbore. Vertical
calibration wells demonstrate the earth
model's replicated production attribute
response derived from log and dipole
54 THE AMERICAN OIL & GAS REPORTER

sonic properties.
Cumulative oil was extended from 90
days in early versions of Laredo's production attribute modeling to six months
when it became apparent that six-month
cumulative oil had a stronger correlation
to oil EUR. Given that oil production
provides approximately 80 percent of
Laredo's total revenues, the production
attribute derived from this earth modeling
approach has become a fundamental
value creation driver in field development
planning.
The production attribute shows that
zones of higher production potential evidently are laterally extensive, related to
depositional facies and structural setting
within "like" rock properties. A key ob-

Two-Step Process
The primary production attribute validation consists of two steps. The first
step involves recreating the production
attribute at specific well locations using
modern electric logs with dipole sonic
data. This was accomplished by applying
an iterative multivariate approach to match
an equivalent response derived from the
production attribute. Overall, a good
match was observed using this proprietary
in-house process, which resulted in a

FIGURE 4
Example of Two Wellbores Landed in
Different 3-D Production Attribute Zones
Above Type Curve

Below Type Curve

Projected 90-day Cumulative Oil: 47,000 BO
7,741' Lateral Length

Projected 90-day Cumulative Oil: 24,636 BO
7,257' Lateral Length
Actual
90-day
Production1

Upper Wolcamp Look-Backs & Type Curve
90-day Cumulative Oil Production
Cumulative Oil Production (BO)

variate model from 2015.
Importantly, a mutual interaction
among reservoir quality, mechanical properties, and natural fracturing appears to
correlate to production. No single parameter or attribute appears to exert an
overriding effect. Given that individual
attributes developed for the study vary
spatially across the area of interest, different attributes contribute in varying
degrees with other attributes, which in
turn, impacts the productive capability.
As opposed to a lone "silver bullet" production driver, the data and resultant interpretation suggest a combination of
variables is the key.

servation is that contrasting zones of low
productivity potential are interbedded
within zones of higher productivity potential. This appearance repeats within
each productive sequence targeted for
development (Wolfcamp series).
When contrasted with lower production
potential attribute values in any given
zone, the higher production potential attribute values illustrated by the earth
modeling process can vary by 50 percent,
thereby significantly impacting EUR and
value. Therefore, the production attribute
represents an important tool for development planning and selecting optimal landing points.
Figure 4 shows an example of two
wellbores landed in different zones within
the 3-D production attribute. The "above
type curve" example demonstrates the
wellbore being located mainly in higher
production attribute values. Conversely,
the "below type curve" example shows
the wellbore located in significantly lower
values of the production attribute.

Percent of
Type Curve

Above Type Curve

45,517 BO

130%

40,000

Type Curve

35,075 BO

100%

30,000

Below Type Curve

26,233 BO

75%

50,000

20,000
10,000
0
0

60
Days

90 100 110 120

American Oil and Gas Reporter - December 2016

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