The use of Expandable Sand Screens (ESS) to Control Sand in Unconsolidated Multi- Zone Completions in the Baram and Alab Fields Offshore Malaysia -- A Case Study

Abstract

The Baram and Alab fields located in offshore Sarawak and Sabah, Malaysia, are composed of highly unconsolidated and friable sandstone reservoirs having multiple pay zones. The primary objective of the application of ESS® was to combat sand control problems while reducing well costs and simplifying operations by replacing gravel packing. The secondary objective of the ESS® application was to maximize productivity by eliminating / reducing skin damage which is inherently associated with gravel packing. Additionally, ESS® maximizes the wellbore radius by the expansion of the screen, facilitating the process of future well interventions and the application of "intelligent" well completions. Three wells in the Baram field were completed using ESS® with mixed success. The lessons learned from the Baram field were later utilized to optimize the methodology of application of ESS® in the two subsequent wells in Alab field. Experiences gathered by other operating companies e.g. Shell Brunei, Shell Expro and BP in the North Sea were also taken into consideration as a step forward in the learning curve to ensure successful installation in the Alab field. Further testing results performed by the vendor were also incorporated in the design and operational aspects of the wells. Consequently, ESS® has been successfully installed and overall objectives were achieved in the Alab field. Since the ESS® hardware was manufactured and installed by a single vendor, the exchange of data and information between various companies was easy to obtain. Study and research findings from the facilities of Shell and the vendor in Aberdeen and Houston were also incorporated in the design aspects of the wells that were completed in the Alab field. Due to the presence of pressure differential between the zones and contrasting reservoir fluid and rock characteristics it was necessary to produce the wells selectively with annular zonal isolation. Attempts to isolate the pay zones in the first well (BA-102) using Expandable Isolation Sleeve (EIS®) were not successful. However, modifications in the design for the subsequent wells (substitution of EIS® by EXP packers) yielded much better results and achieved well objectives. The primary objective of the ESS® application, i.e. sand control, was successfully achieved, based on the analysis of surface fluid samples. The wells are flowing at the expected rates. Sufficient well test / production data is not available on hand to assess the effectiveness of the ESS® in terms of impairment / improvement of productivity. Pressure build up (PBU) tests are planned in order to determine the extent of skin damage caused by the ESS®. Shell Brunei experienced satisfactory productivity index (P.I.) after completing their wells in S.W. Ampa and Champion fields, offshore Brunei1. Innovations and modifications of the existing equipment and methodology of application of ESS® technology are also proposed. These modifications generate cost savings and simplified deployment for the operator. Introduction As an emerging technology in well completions the application of Expandable Sand Screen (ESS®) is being accepted in the oil industry as a simple and reliable method of sand control with the additional benefit of improved well productivity. Previously, the sandy reservoirs of Petronas Carigali were completed by either gravel packing or fracpacking.