Production logging in horizontal wells presents particular challenges, especially when they are completed uncemented using prepacked screens or slotted liners. These challenges are attributed to well geometry, i.e., the existence of severe doglegs and undulations, where trapped fluids that could directly affect and influence data readings from the tools, such as stagnant water, may lie either inside or outside the liner in low areas at the bottom of the well, or stagnant gas that may accumulate on the high side of drain-hole undulations.
Considering the challenges mentioned above, an integrated horizontal multiphase production logging tool (IHMPLT) is usually required, and in many cases this tool needs to be complimented with a pulsed neutron logging tool (PNLT) to have a more accurate reading of fluid entries.
Over the last 20-years, coiled tubing (CT) equipped with electric cable has been widely used to conduct production logging in horizontal wells, and more recently, CT equipped with an optical fiber has eliminated the restrictions associated with CT equipped with electric cable while enabling several advantages, such as distributed temperature sensing (DTS) to compliment production profiles from IHMPLT. The previous system was unable to run PNLT.
To tackle the above described limitations, and having a more robust portfolio of production logging available, a new solution of real-time downhole measurements via CT equipped with fiber optics has been introduced to enable real-time data acquisition of DTS, IHMPLT, and PNLT logs.
This paper discusses the case history of this first worldwide application. It also provides lessons learned and perspectives for this technology.