American Oil and Gas Reporter - February 2017 - 55

SpecialReport: Shale Resource Science
FIGURE 5
Northern Alabama Mature Field Multiphase Pump Application

STUART L.
SCOTT

ages can occur while transporting a fullwell stream flow of unprocessed fluids
in a multiphase flowline. Fortunately,
blockage detection methods are available
to monitor flowlines and detect blockages
before they become a critical issue. Blockage prevention usually is addressed by
using chemical inhibitors and periodic
pigging.
In regard to managing flow patterns,
slugging is the most troublesome flow
pattern, and large slugs can fill separators
at the central processing facility. Multiphase pumping generally results in smaller
flowlines than systems designed for natural
flow, which must be sized to minimize
frictional pressure losses from the pad to
the central facility.
Slug diameter has been shown to be
directly proportional to pipe diameter, so
smaller-diameter flowlines reduce the
lengths of slugs and the troubles they
generate. In addition, any slugging from
wells will be mitigated by the PD pump,
which will supply a constant volume into
the flowline regardless of GVF.
Material selection and inhibition can
mitigate most risks associated with corrosion/erosion. Sour service parameters,
such as hydrogen sulfide and carbon
dioxide content are needed as the MPF
equipment is specified and the flowline
is designed.
Northern Alabama Project
In early 2015, a project was begun for
Crosbys Creek Oil & Gas LLC, an independent producer in northern Alabama's
Choctow County. The goal of the work
was to restore flow for mature wells that
were struggling to overcome a line pressure

of 700 psig. A Leistritz L300™ twinscrew multiphase pump was designed to
reduce back pressure on the wells to 200
psig. Liquid rates of 300-1,000 barrels a
day and gas rates from 500,000 to 1
million cubic feet a day were typical for
this field. At the new, lower pressure,
this translates to 6,000-14,000 bbl/d equivalent rate (gas and liquid) and a 95 percent
GVF.
A complete skip with recirculation
piping and liquid knock-out boot downstream of the pump was delivered with a
400-horsepower, 1,800-rpm motor and
VFD. The system was designed for remote,
unmanned operation with a completely
self-supported power supply. Figure 5
shows the boosting system during installation. Installation and commissioning
took place during second quarter 2016.
It is now possible to use multiphase
pumping and metering as a cost-effective
alternative to the traditional production
facility designs the oil and gas industry
has installed for decades. An MPF has

Stuart L. Scott is director of technology at Petroleum Emerging Technology Corporation (PetroleumETC).
From 2008 to 2016, he managed Shell's
deepwater artificial lift technology
program and served for several years
as Shell's global artificial lift/pumping
principal technical expert. Before joining Shell, Scott held the Bethancourt
Professorship of Petroleum Engineering
at Texas A&M University, was a faculty
member at Louisiana State University,
and worked for Phillips Petroleum
Company in a variety of roles. He is a
distinguished member of the Society
of Petroleum Engineers and received
the American Society of Mechanical
Engineers Henry R. Worthington Medal
for "eminent achievement in the evolving field of multiphase pumping." Scott
holds a B.S. in petroleum engineering,
an M.S. in computer science, and a
Ph.D. in petroleum engineering from
the University of Tulsa.
the ability to reduce costs and HS&E
risks/impacts, while also improving recovery (through pad compression) and
well/reservoir/facility management
(through frequent automated well testing).
These advances are so significant that
they have the potential to differentiate an
operator in the areas of production excellence and lowest life-cycle cost. r

BHP Billiton's Gulf Well Offers Encouraging Signs
MELBOURNE, AUSTRALIA-BHP
Billiton says its Caicos exploration well
in the Gulf of Mexico encountered oil in
multiple horizons. The well, 100 miles
south of the Louisiana coast in Green
Canyon 564, was drilled to a total depth
of 30,803 feet.
"We are encouraged by the Caicos results, and are moving to further appraise
the area," says Steve Pastor, president of
operations, petroleum, for BHP Billiton.
The company, which operates the well,

spud the well June 21 in 4,225 feet of
water as part of its Shenzi North field
appraisal.
According to the company, it intended
to begin drilling its Wildling well in November to further appraise the area. BHP
Billiton says it plans to spend $700 million
in exploration for the 2017 financial year,
largely focusing on drilling activities in
the Gulf of Mexico and Trinidad and Tobago.
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FEBRUARY 2017 55

American Oil and Gas Reporter - February 2017

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