Array Production Survey Accurately Pinpoints Water Shut-Off Location and Strengthen the Understanding on Remaining Potential of a Giant Carbonate Gas Field, Offshore East Malaysia

Abstract

Over the years, Multiple Array Production Suite (MAPS) has been run several times in Offshore Peninsular Malaysia but never in Offshore East of Malaysia. Field A is located 260km North-North West of Bintulu, Offshore Sarawak and was discovered in 1992 with first gas produced in 2004. One of the many challenges currently faced in managing the field is the prediction and handling of water breakthrough at the existing producers. Based on historical data, water breakthrough from carbonate Zone T begin around 2010 which then followed by series of Water Shut-Off (WSO) campaign. To strengthen the understanding, evaluate the remaining potential and to optimize near term well and reservoir management of the field, an integrated remedial approach is essential. Well-AA was identified for mechanical WSO in an effort to remediate high water production and improve well productivity. The target well was chosen as the well unable to sustain production after a rapid tubing pressure drop due to the highest water production in the field. Moreover, its production had to be capped due to the water production constraints at the receiving hub. Production Logging (PL) was planned across the carbonate sections to accurately identify the appropriate zones for WSO operations. The long horizontal section and high water production typically create a stratified flow regime that forces a smaller volume of hydrocarbon to flow on the high side of the well, hence the conventional PL technology would have been unable to deliver accurate and insightful results. As such, the MAPS technology was run for an initial assessment to identify the water producing zones. MAPS was deployed using wireline tractor and was combined with the Noise Tool (NTO) to provide a comprehensive 3D image of the multi-phase flow profile across the entire wellbore and to investigate the integrity of annular swell packers located in between the carbonate sections. This paper illustrates the best practices involved in the successful downhole Production Logging with a Multiple Array Production Suite and Digital Noise Tool (PL-MAPS-NTO) toolstring, which served as the key input in determining the WSO treatment depth and strategy in Well-AA, that may lead to a potential gain of 10.8MMscf/d.

Application and Analysis of Array Production Logging Technology for Multiphase Flow in Horizontal Wells

“…During reciprocal logging tasks, the FSI instrumentation showcased inconsistencies in the quality and repeatability of rotor-derived information throughout sections 3-8 (down to 4600 m) alongside suboptimal data collection from probes 1, 3, and 4, affecting the veracity of the waterholding probes' output. However, FAST instruments registered standard rotatory data within the uppermost sections (3-7 (extending beyond 4700 m)), indicating environmental resilience, as well as superior-quality data collected across the subsequent segments (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21).…”

“…Despite the successful demonstration of fluid profile visualization via conventional logging tools in vertical wellbores, addressing the issue of phase separation [13], there are certain limitations in high-gradient or horizontal wells. Specifically, the upper portion tends to contain lighter phases [14], while the lower regions harbor heavier phases, particularly at the base of horizontal wellbores, where sedimentation phenomena can potentially occur. Such occurrences pose constraints on the regular operation of measuring equipment, leading to acquired data that fail to provide an accurate representation of the flow attributes of horizontal wells [15].…”