Shell Malaysia Upstream operations offshore Sabah and Sarawak in the South China Sea have been utilizing a data driven Virtual Flow Metering System to provide gas production estimates in real time for close to a decade. More recently, the analytics aspect of the system is helping to detect liquid loading in gas wells, support Exception Based Surveillance (EBS) and optimize chemical injection. In the absence of multiphase flow meters, a Virtual Flow Metering System may be used for well by well production rate estimation. This has been implemented for the oil wells in a deepwater facility in Sabah, enabling onshore production support teams to monitor production from each well in real time. It is a cost effective approach to project delivery while enabling safe and reliable production. Production estimation by the Virtual Flow Metering System is derived from data driven models built using a series of well tests. These models are updated as often as well tests are performed and compared to the export meter to constantly validate the accuracy of the well-by-well production estimates. For superior wells and reservoir management and to maintain asset integrity, exception based surveillance (EBS) is required. A large number of complex EBS requirements are being monitored in real time, using the signal processing and pattern detection capability of the Virtual Flow Metering System as the calculation engine. The intent of the EBS system is to alert onshore operations when a user defined operating limit is exceeded to facilitate actions to be taken in a timely manner. Some examples of EBS implementation are for sand detection and the quality of injected water and gas. Additionally, the EBS system is being used to detect liquid loading in mature Sarawak gas fields, leveraging on recent best practices reported elsewhere within the Group. More recently, this Virtual Flow Metering System usage has been extended to provide Real Time corrosion inhibitor flow monitoring with the aim to track injection rates and keep injection on target, while minimizing excess chemical costs. Within days of the deployment of this real time surveillance tool, high injection alerts detected have resulted in significant savings. Over the same period, detection of low injection has allowed faster adjustments to increase injection and thus minimize corrosion effects to the pipelines.

0. Abstract Historically, oil and gas producing fields had sufficient capacity to fulfill contractual requirements. Today, most operating companies are finding it ever more challenging to meet contractual requirements on LNG cargos and/or oil tanker loadings. For gas producing assets, the gas produced will feed LNG trains or a power plant directly. And as the feed gas needs to meet specifications on H2S, CO2, Gross Heating Value, etc… there is little room to play. Generally, this blending problem is well understood at the medium to long-term planning level. But, in day-to-day operations, there will be events that force operations to divert from the long-term plan. And this is where Real-Time Asset-Wide Optimization (RT-AWO) comes into play. This paper details how RT-AWO was deployed and is used in a major Shell operating unit in Asia-Pacific. This asset has a complex gas-producing infrastructure where a combination of different production sharing contracts, third party producers with an ever-changing demand from the LNG plant and strict quality requirements. Having RT-AWO it is now possible to run the field in the most optimal way, all day and every day, while taking into account all possible constraints (wells, topside and pipeline). The RT-AWO has proven to be very successful. Despite the complexity of the network, the tool is very user-friendly and easy to maintain. Not only does it allow the central control room operators to push the field to the limit, it provides them with accurate CO2 forecasts for up to 18 hours. And it takes less than a minute to compute. The RT-AWO is a novel approach to a complex problem, sustainable, easy to maintain and use. It provides an integrated view with real-time information, forecasting and optimization functionality. And if is flexible enough to be deployed in other locations with even more complex networks.