Optimizing Usari Field Production Through Effective Sand Management

Abstract Usari field is known for its sand production history. The first sand production incident occurred in 2001 when a choke had a pin-hole leak resulting from sand production/erosional effect. Since then, produced sand and residual sand in sub-sea pipelines have caused recurrent failures of surface rotating equipment (pumps), frequent de-sanding of vessels and topsides and volumetric downtime (deferred production) associated with total platform shutdown or restricted production. In the past, sand management and surveillance activities included conducting bucket and screen (B&S) sand checks or sampling on all flowing wells as part of monthly routine well test; utilizing a hydro-cyclone sand trap to conduct comprehensive sand checks on identified sand producing wells and establishing sand free production rates; monitoring wells to ensure they are flowing at established sand free rates; and carrying out periodic de-sanding of surface vessels and topsides. A step change in the approach to sand management and surveillance in Usari field was implemented in 2009, when a multi-functional team was chartered to develop procedures for Usari startup and post-startup operating philosophy. In addition to existing sand management practices, the team implemented bucket & screen (B&S) sand checks at strategic topsides locations (upstream of the separator and at the main online pumps (MOLP) suction). The team also developed a spreadsheet to calculate sand production rates and established benchmarks for acceptable sand production rates through the MOLPs. The team provided on-site supervision of startup activities and monitored sand surveillance activities through the Asset Level Team (ALT). Usari field was successfully restored to full production and currently produces at over 120% of post-startup average production. Wells were produced at maximum sand-free rates and disruption to continuous production due to sand-related platform shutdowns were minimized, thereby maximizing value in a sand- prone asset. Post startup, the team continues to provide guidance to field operations, and sand surveillance results are reviewed during ALT meetings.