Identification of Behind-Casing Flowing Reservoir Intervals by the Integrated High-Precision Temperature and Spectral Noise Logging Techniques

Abstract

Abstract Hydrocarbon production from low permeability reservoirs has been steadily growing in the Russian Federation lately. The reservoir sweep efficiency and behind casing integrity has become even more important than it was in conventional formations – mainly because the target oil/gas pays has experienced tough competition from higher permeable water pays. In high permeability formations one can normally track production profile with a conventional production logging tool based on a mechanical spinner and based on that schedule the treatment to arrest water cut growth. In low permeability formation most communication happen behind the casing and those flowing inside the borehole are usually too slow to be captured by the mechanical spinner. This paper shows how high-sensitivity broadband Spectral Noise Logging [1–4], High-Precision Temperature Logging [1] and flow modeling in combination with conventional production logging can produce valuable information on gas, oil and water flow profile and behind casing communication (whether a cement rim channeling or a reservoir fracture flow). The technology is illustrated with three case studies from the East-Tarkosalinskoye field of the Yamalo-Nenets Autonomous Region (North Russia). One case was a vertical well and the two others are horizontal wells with multi-zone hydraulic fracturing. An integrated analysis of acquired data identified the sources of water production and also revealed the non-producing reservoir zones. Special attention was paid to the analysis of annular and behind-casing cross-flows. One horizontal well was worked over with a cementing job around the zone identified as the water source from the HPT-SNL survey and resulted in total shut-down of water production with no impact on oil production.