Integrated Production Logging Approach for Successful Leak Detection Between Two Formations: A Case Study

Abstract

Abstract A major exploration and production (E&P) company is acquiring a significant number of multiphase production logs a year for reservoir management. It is anticipated that this number will increase, when these deviated and horizontal wells start to produce water. It is more challenging when these wells become dead due to downhole communication between an aquifer and the objective reservoir resulting in excessive downhole water dumping. The strategy, therefore, is to run advanced production logging tools (APLT) integrated with the pulsed neutron logging tool (PNLT) to provide velocity along with holdup maps across the diameter of the borehole from an array of sensors and water velocities inside the wellbore or the annulus, respectively. The combination between APLT and PNLT data provides accurate detection and quantification of water zonal contributions. The aim of the three case examples presented in this paper is to facilitate detecting the leak point and assembling the inflow profiles. The first example is an open hole completion. The logging data showed 1000 bbl of down-flow movements in the tubing-casing annulus (TCA) starting from the shallow aquifer. The second well was completed with an inflow control device (ICD). Water dumping was observed from the leak over the blank pipe down to the screen interval, which is also supported by temperature deflection. The third example is a cased-hole perforated completion. An integrated logging approach yielded reliable results in detecting the water entry interval, and the water entry was identified from the perforated section flowing upward to the casing leak. This detected crossflow in the mentioned examples at shut-in conditions was the reason that the wells were dead. The established integrated logging solution and field examples showed evidence that a leaking interval was suspected to be responsible for high water cut, reducing well performance and killing the wells. The source of water production identified provides the justification for a workover to isolate the water entries, secure the objective reservoir, and revitalize the dead well.