Achieving Operation Efficiency and Enhancing Production in a Brownfield With Multizone Gravel-Packed Intelligent Completions: Two Case Studies From Malaysia
The aims of every oil & gas operator to optimize production,
increase oil recovery, and minimize operating cost are driving the industry to
look for innovative completion and production solutions. This is true for
brownfields where operators are looking to rejuvenate reservoirs that still
have reserves in place as original completion efficiencies deteriorated over
A workover and new well offshore Malaysia was conducted in a field to
recover oil from a multilayered, high water/oil contact reservoir. The
objective was to increase production and recovery volumes in a cost-effective
way and reduce rig time. The original completion designs in the field lacked
the ability to control and choke the flow from each zone independently, and
thus could not optimize comingled production and water cut, resulting in
limited oil recovery from the reservoir.
For this reason, an intelligent completion with downhole variable flow
control valves and real-time pressure and temperature gauges was considered.
The objective was to design an intelligent completion that is both cost
effective in a marginal field and that can fit inside a cased-hole wellbore
that requires sand control. Because of the many challenges faced in combining
the multizone gravel-pack system and the intelligent completion components,
both had to be re-engineered to allow for a perfect interface. This resulted in
the first intelligent completion installation inside a shunt-tube gravel pack
with multizone packers and subsequently future wells with same design.
Introduction to the Samarang Field
The Samarang field is made up of several stacked reservoirs, some
partially depleted and some with strong water drive from aquifers. All
reservoirs are sandstones that are mostly unconsolidated to depths of 1,500 to
5,000 ft true vertical depth (TVD) and consolidated from 5,000 to 8,000 ft TVD.
Reservoir pressures range from 900 to 3,500 psi. The field is located 30.5
miles northwest of Labuan, Sabah, East Malaysia. The billion-barrel Samarang
field, offshore East Malaysia, had entered a production decline phase until a
joint risk/reward partnership between a service company and PETRONAS Carigali
Sdn Bhd (PCSB) revitalized the field by designing and implementing a
three-phase redevelopment. The initial phase of the development was carried out
in 2011, when five infill wells were drilled from existing platform facilities.
A second drilling phase of infill wells was carried out in 2013 and 2014 after
a series of platform extensions and upgrades allowed more slots to drill and
complete another 10 wells. Although all of the second-phase wells were designed
as openhole completions, two of them, one being a workover and another being a
new well, was designed as an intelligent completion inside cased-hole gravel
packs. Both of these wells is the subject of this paper.
One of the main goals of revitalizing the field was to reduce the
overall cost of drilling and completing the wells and increase production. A
key area was the completions, which traditionally were installed as dual
strings to maximize the number of layers to be produced with each well. This
was also the completion design of the initial five wells during the first phase
of the redevelopment project.