Search

Abstract Expandable sand screen (ESS) is a sand control technique that has the potential to give a lower skin and therefore better productivity than other conventional sand control techniques, such as internal gravel packs (IGP's), openhole gravel packs (OHGP's), and stand-alone screens. However, welldocumented field cases in public literature that confirm this potential have not been reported to date. Over the last few years, Brunei Shell Petroleum (BSP) has applied the ESS technology in both cased hole and openhole completions. The productivity data of the ESS-completed zones have been used in a comparison with data from similar zones completed with more conventional gravel packs. In openhole applications in BSP's S.W. Ampa and Champion fields, production results show that the Productivity Index (PI) of ESS-completed reservoirs is equal to or better than expected, with one ESS zone having some 50% higher PI than similar OHGP zones. In cased hole applications in the Champion West field, the productivity of reservoirs completed with ESS is similar to or better than the productivity of similar reservoirs completed with IGP's. In all cased and openhole ESS-completions, no indications of sand production, screen plugging or screen erosion have been observed to date. Introduction Expandable sand screen is an emerging sand control technology that can be applied in cased and openhole completions, as an alternative to internal gravel packs, openhole gravel packs or stand-alone sand screens. It offers several advantages over conventional gravel packs: easier logistics, simpler operations (with potential for rigtime savings especially in cased hole completions), larger bore access to the completed zone, better support of the formation in openhole completions, and potential for remedial zonal isolation. It also has the potential to give a lower skin and therefore better productivity than other conventional sand control techniques. The concept and the development of the ESS technology has been described in more detail in Refs 1, 2. Since the end of 1999, BSP has been applying the ESS technology in both cased hole (5 wells) and openhole (4 wells) completions3, 4. In several campaigns similar wells and zones have been completed with ESS or conventional sand control methods, providing excellent comparison material between the two. The production data from these zones have been analysed and used in a discussion on the merits of ESS from the perspective of well productivity. Openhole ESS Applications in S.W. Ampa Field The S.W. Ampa field in the Offshore West concession area of BSP consists of many thinly stacked sand layers separated by shale stringers. Many reservoirs have a history of sand production thus making sand control a necessity. Sand control in openhole completions transecting multiple sand layers is particularly challenging due to shale instability issues. This field had a history of unsuccessful openhole gravel packs thought to be associated with the collapse of shale once the openhole was displaced to brine. Caliper logs showed that with increasing openhole time, the shale section became overgauge while tight spots developed in the sand sections.

The Champion West (CW) field Offshore Brunei, North Borneo consists of alarge number of vertically stacked hydrocarbon bearing reservoirs where thinlayers of laterally continuous shales are sealing the different hydrocarboncolumns. Wells in CW are typically completed selectively on multiple reservoirs (3-5zones) due to contrasting reservoir pressures and fluid properties and forreservoir management purposes. Although the reservoir rock is relativelyconsolidated, sand exclusion has been installed on shallower reservoirsfollowing sand failure in offset wells. Internal Gravel Packing (IGP) has inthe past been the preferred sand exclusion technique. Due to a high deviation in the four CW Early Oil Development (EOD) wells(54-66 deg.), it was desired to incorporate remote operated smart wellequipment to minimise future well intervention requirements. As the large distance between zones would require up to four IGP operationsper well (resulting in high costs) and would not provide sufficientthrough-bore to install the smart well equipment, it was decided to useExpandable Sand Screens (ESS) for sand control purposes in the new wells. Theuse of ESS facilitates multiple zones to be completed in single installationswhilst providing a larger through-bore for the installation of smart wellequipment. The paper discusses the sand-face completion design and installationaspects. As one of the EOD wells was completed with IGP, a benchmarking (rigtime, cost, performance) of the ESS technique is also presented. Finally, recommendations are made which should enable further cost reductions in the future.