High Precision Temperature – Spectral Noise Logging (HPT-SNL) at Well ‘X’ to Identify Zonal Contribution & Behind Casing Communication – A Case Study

Abstract

Well ‘X’ was drilled in a gas condensate reservoir located in Kirthar fold belt with the primary target of P & R formations. During CIT of P formation in April 2012 the well was tested at 4.03 MMscfd gas, 1543 STB/day condensate & 1670 bbls/day water at a FWHP of 309 psi. Available production logging surveys with water & gas holdup tools were performed twice to identify the water producing zones; however the results were inconclusive as commonly used production logging tools are able to identify production contribution only across the perforated intervals and cannot detect behind casing communication and flow within reservoir. The well had been shut-in as plant was not ready for tie-in, so opportunity was taken to conduct HPT-SNL suite (in memory mode with slickline) in August 2013 which resulted not only in identifying the water producing zones but also confirmed hydrocarbon influx zones above perforated interval and flow behind casing from above perforated interval. HPT is a high precision temperature tool with resolution of 0.003oC and response time less than 1 second to capture any small flow, whereas SNL is spectral noise logging tool which can scan noise spectrum through multiple barriers for evaluation of any cross flow behind casing and leakages. Based on HPT-SNL results, water shut-off was performed which considerably reduced water production (from 1318 to 520 bbls/day), consequently reducing WGR (from 628 to 244 bbls/MMscf) with no change in gas rate whereas increase in condensate production was observed (from 330 to 855 STB/day). This paper describes the complete case study of diagnostic logging followed by remedial work to optimize the producing asset value.