Enhancing Reservoir Surveillance and Production Sustainability Through Live Digital Slickline

Abstract Reservoir Surveillance is made increasingly difficult in mature offshore oilfields that contain a large number of wells with all associated infrastructure. While logging requirements are increasing in order to sustain production from the field and maintain well integrity, the production requirement is increasing and the operational cost has to decrease. These challenges are additional to the existing constraints due to resource limitations in an offshore environment: winch boats for equipment movement, slickline units for downhole safety valve retrieval and tubing checks as well as offshore living accommodation limitations are major factors any of which can cause a halt of rigless logging campaigns. A new digital slickline unit was used to replace the conventional practice for rigless wireline logging operations in offshore fields (wellhead towers). The old method involved a slickline unit to perform the pre-job and post job work. That's in addition to the logging unit that performs the required production logging job. This process involved a lot of winch boat moves, personnel and shut in days resulting in loss of production between moves. This digital slickline unit combines the capabilities of a slickline unit and a logging unit. The type of slickline it uses allows sending commands to logging tools downhole and receiving data on the surface data acquisition system while logging. The new approach had multiple operational, financial and HSE&Q impacts. Operationally, performing production logging operations using this digital slickline unit minimized logistics compared to conventional production logging (4 lifting loads Vs. 14 lifting loads). It has also reduced the operation time and trips to and from wellhead towers which resulted in reducing production losses. It also helped achieving the increasing annual logging and slickline KPI's without compromising data QC. Furthermore, HSE&Q was addressed by providing a solution for some integrity concerns related to wells being left with no downhole safety valves between slickline and logging unit movements. Moreover, the probability of incidents caused by improper handling of equipment and tripping/slipping hazards was reduced and most importantly, the option of Medevac by chopper became available in emergency cases due to the reduction in the occupied tower area. This breakthrough in logging operations from offshore wellhead towers enhanced the operational quality and reduced cost. It represents a part of the continuous efforts to reshape the concept of production and reservoir surveillance (which includes well testing, pressure surveys, etc) by applying new technologies and following new approaches to allow fulfilling larger requirements without making compromises on HSE&Q, production requirement and cost efficiency.