Date of Publication :11th September 2023

Abstract: Crossflow exists when there are zones with dissimilar pressure properties allowed to communicate during production. Reservoir fluid from a high-pressure zone will flows preferentially to a low- pressure zone except if the production parameters are well controlled. A poor cement bonding often creates unwanted conduits behind casing that leads to crossflow between multi-layer of producing reservoirs. A conventional Memory Production Logging Tool (MPLT) that consists of mechanical spinners routinely run to perform quantitative assessment of each sand’s contribution for production allocation in Malay basin fields. Detecting and quantifying crossflow behind casing is impossible using the conventional PLT as the tool is deployed inside the casing. Thus, advanced additions to the conventional production logging tools using High Precision Temperature (HPT) and Spectral Noise Logging (SNL) which aim to address the issues. This research aims to study the detection of behind casing crossflow and reservoir allocation by using spectral noise and temperature modelling in Malay basin. The research specifically based on a dual completion well of which Z-01L string was completed as an oil producer, flowing gas lifted from Z-35L sand, while Z-01S string completed as oil producer, flowing gas lifted from Z-35U sand. This research is based on secondary data obtained from an oil and gas industry in Malaysia. The data was analyzed and interpreted to investigate the communication between sand Z-35U and Z-35L crossflow behind casing. The research suggested that combination of HPT-SNL-PLT logging is crucial in investigating the crossflow behind casing. The results of the study also suggested that a holistic data acquisition program by combining conventional and advanced tools is vital for the quantifying the true zonal production allocation. It is hope that the study can contribute to the improvement of a field-wide scale reservoir allocation and long-term production strategy in Malay basin.

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