The Use of Expandable Sand Screen to Prolong ESP Runlife in a Mature Field with Severe Sand Production Problems
Authors: Caretta Fausto , Putra Rafliansyah A. , Lavie Franck , Martin A.N. 
Published: October 2008

In Repsol YPF Maxus SES, South Business Unit (SBU), hydrocarbon recovery is mainly from two reservoirs. One of which is the Talang Akar Formation (TAF), a typical sand stone. Since production started in the late 70's, these reservoirs have depleted considerably. From experience, these sand stones produce sand because of unconsolidation, which becomes more critical with the onset of declining reservoir pressure. The entire field is drained utilising Electro Submersible Pump (ESP). Sand production compromises production, through failures of this artificial lift system.

The conventional way to reduce or eliminate this problem is by installing a sand control solution. Historically the popular technique of sand control is gravel packing and when combined with fracture stimulation of the productive layers, it can lead to improved inflow performance. Unsatisfactory results have been obtained through gravel packing with considerably high damage / skin factors being observed.

The new leading edge technology in sand control, Expandable Sand Screen (ESS) can address these problems, improving reservoir / completion inflow performance. Field tests in differing environments have shown very encouraging results in both open and cased hole applications.

For short interval, cased hole applications, as required by the SBU, the cost is competitive with frac pack solutions. Placement of proppant in the perforation tunnels or possible cavities behind the casing decreases the likelihood of perforation tunnel collapse / plugging, after the ESS installation. By installing this sand control solution, it is anticipated that ESP runlifes will be prolonged and therefore considerably improving operating field costs.

Field and Reservoir Characteristics

The Cinta field is located 80 km North, offshore Southeast Sumatra and falls within the hydrocarbon provinces of the Northwest Java and Sunda basins. It derives its production primarily from the Late Oligocene-early Miocene Talang Akar clastic. Talang Akar Zone 1 consists of point bar channel sands, which are laterally confined and commonly separated vertically and laterally by shales. This results in poor communication between both the underlying Zone 2 sands and within individual Zone 1 channel sands. Talang Akar Zones 2, 3, and 4 are comprised of thick, multiple stacks of fluvial deposits, which lack continuous shale barriers, although depositional heterogeneity results in a broad range of porosities and permeabilities with small, isolated shale barriers distributed randomly throughout the reservoir. All four zones are unconsolidated with minimal consolidation being observed in the upper sands, increasing gradually to the lowest.

The field was discovered in 1970. More than 120 deviated wells have been drilled, with only half of these producing today. The average reservoir depth is approximately 3,400' SSTVD. With over 30 years of continuous exploitation the reservoir pressure has depleted from 1488 psi to about 710 psi nowadays. The average porosity is in the range of 25 to 28% with permeabilities differing from 500 to 2000 mD. The primary drive mechanism is moderate water drive combined with solution gas drive.