PBIOS - October 2018 - 153

Residual Oil Drives New Resource Play
Discovery Well
If one ignores the few horizontal wells
experimentally landed in the main pay
intervals of the larger fields, Andrews
County, Tx., is commonly credited as
the locale with the first San Andres horizontals. The earliest of those were 2010
step-outs just outside the long-established
boundaries of legacy fields such as Shafter
Lake and Fuhrman-Mascho.
Shortly thereafter, a "tight oil" prospect
was attempted in western Yoakum County,
Tx., where the first well, the Broken
Spoke No. 2 State (actually just across
the state border in Lea County, N.M.)
was drilled in April and May of 2013.
The mile-long lateral was completed with
a hydraulic fracture treatment by Manzano
Resources as though it was the carbonate
equivalent of a tight shale well. The well
began initial production that summer, but
was producing only large volumes of
water for 30 days until it began to cut oil.
The operator was hauling water until the
oil production rose to more than 200
bbl/d, at which time the decision was
made to drill a disposal well.
Manzano Resources began sustained
production in late March 2014 and filed
the completion report in May 2014 after

disposing of a total of more than 80,000
barrels of water (more than its entire
stimulation "load" volume). The well had
begun cutting oil only after reaching a
pump intake pressure of 1,315 psi, down
from an initial pressure of 2,130 psi. The
No. 2 State well has gone on to produce
150,000 barrels of oil.
Figure 1 recaps the entire 48-month
oil production history of the Broken
Spoke discovery well with a hyperbolic
fit projecting a cumulative oil recovery
of 250,000 barrels at 10 years and estimated ultimate recovery of 350,000 barrels.
With the success of this Broken Spoke
lateral, Manzano proceeded to drill six
more wells in rapid succession. Table 1
shows the summary characteristics of the
seven wells.
These initial wells in Western Yoakum
were all drilled in a regional "graveyard"
area littered with dry and noncommercial
vertical wells dating back to the 1950s.
The excitement of the production from
those initial horizontal wells gave cause
to suspect that something new was occurring. Clearly, the wells were not
completed in tight intervals (as was
originally supposed) and the sustained
fluid production with a delayed onset
of oil cuts suggested something different
was happening.
As a result, operators began to refer

FIGURE 1
Broken Spoke No. 2 Well Oil Production with Hyperbolic Fit
400

400
Actual Broken Spoke Production

350

Hyperbolic Fit

300

Cum. Oil (Fit) in Mbo (Rt Scale)

250

200

150

100

Cumulative Oil (Fit, bbl)

MIDLAND, TX.-The headlines today
are, quite justifiably, all about "shale
play" investments and the huge impact
they are having on America's energy supplies. One of the main secondary stories
is the amazing Permian Basin and its
newly recognized status as a global superbasin.
But it was not that long ago that the
Permian was in the midst of a long-standing declining trend, with oil production
falling to a 50-year low point of 840,000
barrels of oil a day in mid-2007. Move
forward to mid-year 2018 and production
has risen to a level never seen before in
the long history of the basin: 3.2 million
bbl/d and counting.
This has been an amazing accomplishment and a tribute to the American
ethos. So much excitement and momentum has occurred that it is quite easy to
calculate that more than $200 billion of
new drilling investment capital has
poured into the Permian Basin over the
past decade. It seems that multibilliondollar projects are announced each
month. Seventy percent of all new drilling
since 2007 has been horizontal, and almost all of it within the Delaware and
Midland sub-basins. But very quietly,
the historically reliable producing carbonate shelf reservoirs have been making
their mark, too.
Today, more than 1,000 of the 20,000
new horizontal wells have landed in the
San Andres and Yeso carbonates, with
the percentage gradually increasing from
less than 2 percent in early 2012 to 5
percent today.
This article focuses on the horizontal
well play targeting the San Andres formation in particular, and addresses the accelerating development of what is becoming
the "second resource play" after the multiple
shales being developed in the Midland
and Delaware basins. However, the San
Andres resource play can be thought of as
a conventional reservoir with an unconventional (residual) oil, in contrast to the
Wolfcamp Shale, for example, which is
an unconventional reservoir with a conventional oil. The difference will prove
interesting as some valuable attributes of

conventional rock should lend this San
Andres play a very long life.

Oil Production (bbl/d)

By Steve Melzer

0
0

60
Months

108

120

OCTOBER PBIOS 2018 153

PBIOS - October 2018

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