The Jintan giant carbonate gas field in the Central Luconia Province, offshore Sarawak, Malaysia, has been on production for more than 8 years. One of the main challenges currently faced by the subsurface team is the prediction and handling of water breakthrough at the existing producers. To optimise near term well and reservoir management, but equally important to evaluate the remaining potential of the field, an integrated approach and robust understanding of the field is essential. This paper explains how Shell Malaysia with support from their partners are using a combination of 4D seismic technology, reservoir surveillance, and integrated reservoir modelling workflows to achieve this objective.All the producing wells are situated in the northern, crestal area of the field, whereas the southern part of the field extends up to 5 km away from the nearest producer. A reservoir surveillance program has been in place since first gas via a deviated well, dedicated to monitoring fluid contact movements on a yearly basis. To complement this, two time-lapse (4D) seismic surveys have been successfully acquired in 2008 and 2012, which provide a field-wide image of the top-sweep contacts. The 2008 survey was limited to two narrow swaths located around the surface facility platform area to assist in the targeting of two in-fill producers, successfully drilled in 2008 and 2010. In 2012, much larger 4D swaths were acquired which cover the majority of the field. This high-quality data has provided crucial information on sweep, including a very strong indication that gas has been produced from a wide area. This includes the southern part and edges of the field, enabling in a clearer definition of future development plans.Our ability to use 4D time lapse datasets and surveillance data to effectively constrain the static and dynamic models allowed the delineation of the dynamic behavior of different reservoir geobodies (reef margins, karst, faults) through the production lifetime of the field. This has given insights into the controls on water influx and sweep which can be transferred to other carbonate reservoirs and fields with less data, to better understand and predict their likely dynamic behavior. To assure the quality of the models used for this purpose, in-house best practices have been employed, including 3D Close-the-Loop to assure the quality of the static model and 4D Close-the-Loop to assure realistic fluid dynamics of the field. Experimental design has also been used to capture and dynamically model a realistic uncertainty range. This will enable better production forecasting, and thereby help to define, optimize and realize the remaining opportunities.

One of the small assets in Shell Malaysia E&P has adopted a methodology earlier implemented by Aera in California, USA, hereafter referred to as "LEAN." The concept is to increase organization efficiency by applying Toyota manufacturing principles. This is achieved through continuous improvement of processes, while minimizing waste. Before implementation, an assessment of the pilot asset revealed fragmented efforts and inefficient collaboration between different disciplines supporting Well & Reservoir Management. In general cycle times between identification of problems and closing them out were long and below corporate standards. The pilot project yielded almost immediate benefits. WRM cycle times were reduced by an average of 60% through co-location of key disciplines and work standardization. This enabled the existing well production to significantly exceed targeted production and a clear reduction in overall field decline has been observed. The key conclusion is that LEAN practice, originally directed towards manufacturing operations, is a highly effective way to overcome performance issues in existing assets, and can be replicated globally across diverse operating environments. This paper will reveal new information from field operations, and demonstrates two technical contributions: detecting events from ongoing field surveillance activities such as well tests and real time meter monitoring, and dispatching a continuous flow of modeling, planning and remediation tasks to keep pace with events. Introduction Late 2007, one of the Shell Malaysia E&P assets was chosen as a pilot to implement "LEAN" methodology, earlier implemented by Aera in California and originating from Toyota's manufacturing plants. The asset consists of five mature oil fields in shallow waters offshore East Malaysia: The subsurface is relatively complex and some 200 producing strings are operated, connected to some 100 different reservoirs. Facilities are generally old (up to 30+ years) and the asset has suffered from several years of relatively poor reservoir surveillance, low levels of (well and facility) intervention activity, and slow response to performance anomalies, partly caused by more focus on the much higher value big assets. Net oil production was declining rapidly. To kick-start the Well & Reservoir Management (W&RM) improvement effort, a high level Leadership Intervention Workshop was conducted to identify and agree overall improvement priorities, and a 'LEAN Breakthrough Team' was formed to spearhead "The Aera Way" of working. This meant that 'Fix-the-Basics' activities and 'LEAN Process' implementation had to take place in parallel. This article briefly describes the recent journey and reports some of the key results and learnings. Fix-The-Basics At the end of the dedicated Leadership Intervention Workshop in November 2007, a plan to improve key elements of W&RM foundation was prepared. This was done by first carrying out a detailed assessment to identify gaps and a subsequent Gap Closure plan was executed. One of the key elements of the Fix-the-Basics activities was to repair instruments and sensors; a list of over seven hundred W&RM critical sensors and meters was entered into SAP (the planning and financial database) for repair, and this workload was completed by Q3 2008. A second major effort that was executed was building the integrated production system models (IPSM's). This is seen as a key requirement for quality decision making.

No abstract

No abstract