Case Study: North Texas Well Producing Company identifies new gas pay in cased wells with SLB Pulsar spectroscopy service

Stand-Alone Cased Hole Logging Accurately Distinguishes New Gas Pay from Tight Zones

SLB worked with North Texas Well Producing Company to identify new pay zones in a producing well that had been completed without any openhole logs. The challenge was to determine whether any gas-bearing intervals remained unseen in the cased well, which had 5½-in casing and no tubing.

SLB ran the Pulsar multifunction spectroscopy service, including the fast neutron cross section (FNXS) measurement, to evaluate the well through casing without openhole data. The service distinguished a true gas-filled porosity zone from several tight zones that conventional cased-hole neutron indicators had also flagged as gas bearing, enabling a complete petrophysical interpretation and confirming the uppermost interval at about X,790–X,800 ft as the only gas-bearing zone.