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 time.

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.