Brunei is a significant player in the world
oil scene. Published reports have it producing in the neighborhood
of 180,000 barrels of crude oil per day. Revenues from the sale
of oil and natural gas account of over a third of the country’s
Gross Domestic Product (GDP). Brunei ’s location, close to
the shipping lanes of the South China Sea, adds to it strategic
importance in the world energy market. The driving force behind
Brunei's
oil industry is Brunei Shell Petroleum (BSP). While other oil producers
have been allowed in the country, BSP is still the largest and
most active.
Oil production in Brunei peaked in
the late 1970s at approximately 240,000 bbl/d, it has since been
cut back in order to extend the life of the oil fields. In an
effort to further Brunei's
oil producing capabilities, BSP is exploring other regions of the
country for oil, specifically underwater. The Champion oil field
is Brunei's best producing offshore oil field. The new Champion
West oil field is said by experts at BSP to be one of the largest,
untapped oil and natural gas resources in Brunei. It’is
estimated that the Champion West field will be Brunei's
mainstay, producing oil and natural gas, for the next 20 years
and beyond.
Developing Resources
As part of Champion West
development, a new drilling platform, CWDP-1, was constructed at
the S-42 construction yard on the Belait River. The platform topsides,
which weigh 1000 tonnes needed to be skidded onto a barge in the
adjacent river for load-out. However, structural engineering calculations
indicated that the ground and sheet piling at the riverside were
not strong enough to support the foundation load from the skid
beams during load-out.
BSP developed a plan for the strengthening
of the skid beams by supporting them with piles. The design required
the contractor to drill six through-holes at each of the 1.5 m
wide skid beams for installing 50mm tie rods. After installing
the twelve tie rods and grouting into the holes for the two beams,
piling work was ready to begin. To make the situation more difficult,
the head room between the bottom of the platform and the ground
was only 8 meters.
In order to strengthen the piling,
four 609mm diameter pipes needed to be installed vertically to
a depth of 31.5m. Also it was important to avoid any disturbance
or change in physical property of the skid beam and the existing
sheet piles. After much consideration, BSP decided to use pipe
ramming equipment from the TT Group to install the pipes. According
to pipe ramming specialist, Mike Schwager, TT Technologies, Aurora,
Ill. USA, the rammers chosen for the project were well suited for
this type of work. He said, “For
the Brunei project BSP was dealing with a limited amount of head
space to drive into the ground vertically. They chose to use a
mini-ramming machine at the start and finished with a larger ramming
tool.”
A 270mm diameter Grundoram Mini-Gigant and
a 460mm diameter Grundoram Goliath were chosen for the project.
With the assistance from a TT Group engineer from the United Kingdom,
contractor Yura Oil Tools SDN BHD together with Trenchless Technology
(FE) PTE LTD and Ban Tiong Soon Contractors PTE LTD, were able
to get the project moving and start ramming operations.
Ramming
Basics & Benefits
Trenchless
pipe installation through ramming is a basic process that can have
amazing results. A pneumatic hammer is attached to the rear of
the casing or pipe. The ramming tool, which is basically an encased
piston, drives the pipe through the ground with repeated percussive
blows.
Ramming tools, in general, are
capable of installing 101mm through 3,100mm diameter
pipe and steel casings. Ramming requires minimal working
depths and is proven effective for horizontal, vertical,
and angled applications. |
A cutting shoe is often welded to the front of the lead casing
to help reduce friction and cut through the soil. Bentonite or
polymer lubrication can also be used to help reduce friction during
ramming operations.
According to Schwager, several options
are available for ramming various lengths of pipe. He said, "An
entire length of pipe can be installed at once or, for longer
runs, one section at a time can be installed. In that case the
ramming tool is removed after each section is in place and a
new section is welded on to the end of the newly installed section.
The ramming tool is connected to the new section and ramming
continues. Depending on the size of the installation, spoil from
inside the casing can be removed with compressed air, water,
an auguring system or other types of earthmoving equipment."
Some casing installation methods are
impaired or even rendered inoperable by rock or boulder filled
soils. Pipe ramming is different. During pipe ramming, boulders
and rocks as large as the casing itself can be "swallowed up" as
the casing moves through the soil and can be removed after the
installation is complete.
Ramming tools, in general, are capable of
installing 101mm through 3,100mm diameter pipe and steel casings.
Ramming requires minimal working depths and is proven effective
for horizontal, vertical, and angled applications. Ramming is also
ideal for installations under roads and rail lines because it displaces
the soil without creating voids or slumps.
On the Job
Because of limited head room and
working space, crews utilized a Mini-Gigant pipe rammer
to vertically ram pipe piles. At 1230mm in length, the
mini pipe rammer is substantially smaller than standard
size rammers, but still offers plenty of power at 2000
Nm of impact energy |
In order to install
the four 609mm diameter, 25mm wall steel pipe piles and still
operated within the limited headroom, a Mini-Gigant was used
to push in first 5 m section of pipe. The Mini-Gigant, while
only 1230mm in length, still delivers 2,000 Nm of impact energy
at 430 strokes per minute. Once the pipe was 5m in the ground,
leaving 500mm exposed, a 2m section casing was welded together.
Crews then used the larger, more powerful Goliath to drive
the piles deeper. After positioning the rammer on top of the casing,
the ramming process continued. The casing was installed without
incident. In total, it took 5 hours to install one casing of 31.5m
in 2m per section. Everyone involved with the project was very
pleased with the outcome.
Results
Ultimately
BSP’'s plan worked and the drill platform, CWDP-1,
was successfully out-loaded. A recent press release from Shell
Petroleum confirms the success of the Champion West drilling platform.
In the release Dr Grahaeme Henderson, Managing Director of BSP,
said, “”This is an excellent achievement, as first
oil was planned for February 2006. We are two months ahead
of schedule and have delivered first oil without compromising our
safety and
environmental performance.””
Dr Henderson continued, “”I am
pleased to announce that this well from Champion West has delivered
a record flow rate for BSP. The reservoir is one of the largest
undeveloped resources in Brunei, and will deliver new material
oil and gas production for the next 20 years and beyond for the
BSP shareholders of the Government of Brunei Darussalam and Shell.”
Once each pipe was rammed to a
pre-determined level, a larger rammer was brought in to
finish the job. In total, each pipe was rammed to a depth
of 31.5m. |
Early signs have confirmed that this
well is a record production well for BSP flowing oil at an
initial rate of 16,700 b/d (2,650 m3/d). Champion West is also
producing gas and by 2010, almost a quarter of BSP’'s gas
production will come from this field.
Dr Henderson said, “We are particularly
proud that this platform, comprising the subsurface jacket, together
with the topside
deck and facilities, was designed and constructed in Brune , in
BSP’s fabrication yard in Kuala Belait. This reinforces BSP’s
commitment to develop Bruneian contractors and benefit the local
community”.
The platform is also one of the world’s
most technically advanced offshore facilities and uses downhole
pressure and temperature sensors pre-installed in a fiber-optic
cable, five kilometers in length.
Remote controls, using high bandwidth
connections to the shoreline, are also a feature allowing engineers
in BSP’s Head Office
to continuously monitor the performance of the offshore wells and
facilities improving both production and reserves recovery.
Trenchless Technology International, Spring
2006
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