American Oil and Gas Reporter - January 2012 - 84

Oil & Gas Shales
FIGURE 7
Radioactive Tracer Log (Hixon No. 4H)

Hixon No. 4H
The Hixon No. 4H was El Paso's second well completed in the liquid-rich
condensate window and is located 1.5
miles from the Hixon No. 1H. The lateral
84 THE AMERICAN OIL & GAS REPORTER

length is 4,950 feet (15,033 feet MD and
9,950 feet TVD). The well was completed
with 275 feet of spacing between plugs,
six perforation clusters (three feet with
six shots per foot) and 37 feet between
perforation clusters. The lateral section
was divided evenly into 18 stages.
The per-stage job design was the same
as the Hixon No. 1, except that the maximum proppant concentration reached 5
ppa for most of the stages and larger
30/50-mesh proppant was pumped on
stages 1, 2, 7 and 13, where a report
from Horizontal Solutions International,
a geonavigation/geosteering consulting
FIGURE 8

Production from Bakken Shale Wells with Different Stage Spacing
~250 Spacing

~300 Spacing

~350 Spacing

~400 Spacing

~425 Spacing

~475 Spacing

Single Stage

10,000

1,000
Long-Rate (bbl/d oil)

The job consisted of only one sweep
stage with 10 pounds of linear gel, followed by a linear pad and the main proppant stages ranging from 0.25 to 4.0 ppa.
The plug-and-perf method was used for
isolation. Each stage consisted of 300,000
pounds of proppant (80,000 pounds of
100-mesh sand and 220,000 pounds of
40/70 resin-coated sand) staged from 0.5
to 4.0 ppa with 7,500 barrels of a hybrid
system with 2 percent KCl substitute
treated water. The proppant and fluid
were traced with alternating isotopes and
a fluid tracer. The average surface treating
pressure was 9,400 psi at 80 bbl/min.
Knowing that the Hixon well was in a
liquid-rich condensate area and that multiphase flow would require greater conductivity to adequately drain the reservoir,
the pump schedule was designed with a
more aggressive proppant ramp to help
generate conductivity.
The post-frac log indicated that all 14
stages had communication with the formation. The majority, if not all, of the
perforation clusters had communication
between the well bore and the formation.
However, a count of the interval of propped
section near the well bore, as indicated
by the tracer signature, revealed that only
37 percent of the lateral section was
propped. It also should be noted that the
tracer signature was quite distinct compared
with the Briscoe Nunley (Figure 6).

and reporting services provider, showed
faults going through these sections of
the lateral. All 18 stages were pumped to
completion.
After logging the well post-frac, the
tracer log (Figure 7) showed that all 18
stages were in communication with the
formation. The tracer also showed more
coverage in the lateral than was seen in
the Hixon No. 1H. The interval of propped
section near the well bore, as indicated
by tracer signature, showed that 67 percent
of the lateral section was propped, similar
to the results obtained in the Nunley
Traylor well. In addition, the tracer signatures were quite distinct (it is worth
noting that the propped width indicated
by tracer signatures is larger in the Hixon
No. 1H than in either the Hixon No. 4 or
Nunley Traylor No. 1).
From the tracer logs, it is evident that
the Hixon No. 1H has more spaces between the propped sections compared
with the Hixon No. 4H, and consequently,
less SRV near the well bore. The propped
width also is pronounced compared with
the propped width of the Hixon No. 4H
well. Propped width in the No. 4H well
is strongly influenced by spacing, since
there seems to be competition for space
among the individual fractures compared
with the No. 1H. The spacing in the
Hixon No. 1H seems to allow for creating
larger individual fracture widths.
After six months of data collation, the

100

10
0

25,000

50,000

75,000

100,000
125,000
Cumulative Oil (bbl)

150,000

175,000

200,000

225,000

American Oil and Gas Reporter - January 2012

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