PTTEP's Myanmar Asset Zawtika offshore field is located in the Gulf of Moattama, offshore Myanmar, referred to as the Zawtika Gas Development and Production Area. The area lies approximately 300 km south of Yangon and 290 km west of Tavoy on the Myanmar coast. Zawtika offshore gas field consists of Zawtika Processing and Living Quarter platform (ZPQ) which was designed to provide fully automatic, integrated and centralized platform/ process control, and ZWP1 which is connected to ZPQ via interconnecting bridge and 10 remote wellhead platforms which are ZWP2, ZWP3, ZWP4, ZWP5, ZWP6, ZWP7, ZWP8, ZWP9, ZWP10 and ZWP11, located in the Gulf of Moattama offshore Myanmar. In order to prolong field gas potential, the data analysis, planning and management on daily gas potential loss is important to better understand the field behavior. The issues of gas losses are captured and categorized based on difficulties of recovery. "Deferment" is defined as the short-term temporary reduction in Production Availability which results in delay of gas production due to the effects of system constraints/ limitations, scheduled shut down activities on wells or facilities associated with safety, production, maintenance, operation and unplanned interruptions. "Lock-in" is defined as the long-term gas potential reduction that requires longer time and higher investment to solve and unlock that potential. Under PTTEP Operation Excellent Management System (OEMS), one of the essential elements for optimized operation is deferment/lock-in potential management. With this importance in focus, this paper discusses Deferment Management Enhancement for PTTEP's Myanmar asset operation which goal is to enhance deferment analysis and management by using data analytics in information technology environment in alignment with PTTEP Digital Transformation direction. The data obtained from this enhancement can be used in short-term and long-term planning activities for production system optimization including project investments, reservoir management and integrated operations planning, and especially in providing in-depth analysis to minimize deferment volume to maximize return on investment. Production deferment/lock-in guideline is developed within PTTEP's Myanmar Asset to structure Hydrocarbon Availability Model (HAM) for Zawtika according to PTTEP Operations Standard and define deferment and lock-in gas potential data collection basis and their categorizations. ZPDMS deferment module is then enhanced based on this guideline with the extra capability to facilitate site data entry which has been a problem since start-up due to satellite link constraint from Zawtika offshore field. This enhancement also consolidates lock-in/deferment causes, and coding structures, integrates subsurface potential calculation and surface production data, and introduces key visualization pages (e.g. Deferment Dashboard, etc.) for better deferment management performance analysis. After the full implementation of Zawtika Deferment Enhancement project with the help of a digital platform, the gas potential loss due to deferment can be gained back by unlocking the lock-in potential and reducing the unplanned deferment events by troubleshooting as early as possible from the results of effective deferment analysis and planning. As a result, the yearly average of unplanned deferment was reduced from 68 to 34 MMscfd in 2020 and from 34 to 26 MMscfd in 2021 respectively.

One of the offshore gas fields, the formations are comprised of mixed deltaic and young shallow marine clastic sediments, which are considered among the shallowest unconsolidated and poorly sorted formations, with a high percentage of fines. Along with the sand production issue is the multiple stacked reservoirs that consist of interbedded sand-shale and laminations having undergone gas-water contact (GWC). The proximity of a water leg to the gas column also indicates likelihood of early water production. Water breakthrough can cause significant reserve loss in the gas reservoir and can be even more serious in the sand control completion, which creates a challenge when the two problems combine water and sand. Typical sand control treatments were high-rate water packs (HRWPs) and Extension packs (ExtPacs) or fracture for placement of proppant (FPP). The use of a pad is necessary to maximize the amount of proppant placed into the formation and help reduce overall skin using onsite data analysis. The gravel pack carrier fluid is a viscosified system with shear thinning rheological properties and efficiently suspends sand in static condition. Additionally, this fluid allows substantial flexibility in sand control design for varying degrees of sand support for gravel packing, fluid-loss control, friction-pressure reduction, and a low-damage fluid system (validated with laboratory testing using reservoir cores to validate return permeability values). The objective of the relative permeability modifier (RPM) in sand-control chemical treatments is to prolong hydrocarbon production over time using effective control of water production in one step as a prepad fluid, eliminating the cost and complexity of the water shutoff treatment stage later as part of well life Applying the RPM process has not only reduced water production in these areas but has also resulted in more gas cumulative production. It is also important to monitor production for several months after the treatment to determine the success or failure of the application. Globally, this is the first successful application of RPM delivery in the same aqueous gravel-packing carrier fluid system using a pad fluid, consisting of high-grade xanthan polymer as a gelling agent. Implementation of this process provides the operator an additional tool to increase the possibility of hydrocarbon production from a reservoir that has not been considered viable. Use of the RPM technique in sand-control completions also an option to treat wells after sand-control treatments and control water production resulting from nearby GWC