A viscous heavy crude oil bearing unconsolidated sandstone reservoir of Middle Miocene age is located in a supergiant green heavy oil field that is undergoing execution of first phase of full field development in the State of Kuwait. The screening for enhanced oil recovery (EOR) methods identified Cyclic Steam Stimulation (CSS) followed by Steamflood (SF) as the most adequate combination of EOR methods for the north area of the field.

The field has been undergoing small-scale CSS pilots to evaluate the reservoir potential and to optimize well completion design. To monitor these pilots, well surveillance operations and data analysis are applied and they are playing a critical role in understanding and reducing reservoir uncertainties, a fundamental step for improving recovery and economics of heavy oil field development.

This paper presents a case study of the well surveillance operation performed for well monitoring, well completion design and ultimately production optimization in the ongoing CSS thermal pilots. It describes the different rig less surveillance jobs conducted on the pilot wells utilizing slick line and coiled tubing units (CTU) to monitor sand accumulation and cleaning. This paper also provides details on the tools utilized, their limitations, challenges faced and discusses the interpretation and utilization of the acquired data. Among the tools presented are production logging tools (PLT) which provide data for evaluating steam quality and heat injected into the reservoir. Pressure and temperature surveys assisted in understanding of steam distribution in the reservoir zones. Reservoir saturation tool (RST) are utilized along with dynamic production data for better understanding flow properties in baffle/barrier zone between upper-A and upper-B. Finally cement bond log (CBL) and variable density log (VDL) to gather data for assessing well integrity.

The interpretation of the acquired data assists in further optimization of field development plan.

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