The First Application of a Novel Cased Hole Selective Multi-Zone Sand Control Completion in Gulf of Thailand

Abstract

This paper will discuss completion design and the deployment method of sand control for multi-zone completion wells in the Nong Yao field. The discussion will cover sand control and completion techniques from given reservoir characteristics, in combination with the production strategy. Operational challenges from offset wells will be discussed. The Production strategy for the field required careful consideration for the unconsolidated nature of the reservoirs. An effective drawdown strategy is required as Electrical Submersible Pumps (ESPs) are deployed for artificial lift. The teams designed and implemented a cost effective multi-zone completion (MZC) with selectivity and sand control. The completion was designed to fit in a 7" 23# casing and is comprised of a lower and an upper completion. The complexity of the lower completion; 4" sand screen as outer string, internal 2-3/8" tubing with sliding side doors (SSDs), seal bores and packers, made deployment a challenge with a hydraulic workover unit due to the limitations of stroke length and gin pole. The completion equipment were selected based on workover operations pipe handling constraint, i.e. stroke length, gin poling hanging weight. As the workover stroke length is only 10 ft., R2 range screen and blank pipe was selected instead of the typical R3 range to prevent screen damage when passing through the stationary slip of the workover unit. Moreover, the total screen length combined with blank pipe has to be designed to meet the sand control objectives and stay within the gin pole hanging weight limitation. The lower completion was completed for selective production zone by zone, and was followed by an upper completion (Y-Tool and ESPs) to produce the hydrocarbons. The first well completed as a MZC with selective sand control has been on production for more than six months with no sand checking the base sediment and water (BS&W), even though the well has produced at high water cut and at relatively high rates. This observation shows that the implemented completion design along with production start-up strategy is working well. This same strategy is being applied in future wells.