Better Gas Identification in Southwestern Wyoming

A new epithermal neutron tool, the Accelerator Porosity Sonde (APS), is being used for improved gas identification in Southwest Wyoming. The APS uses a high yield electronic neutron source instead of the chemical source used in conventional neutron tools. It has five neutron detectors that provide both thermal and epithermal neutron detection, as well as borehole shielding, to obtain better porosity measurements. These improved measurements are not as sensitive to borehole environments and lithology effects and thus provide better gas determination. The tool has improved vertical resolution, which is helpful in the thin-bedded, shaly gas bearing sands of southwest Wyoming. This paper will discuss the tool features and compare examples of conventional neutron tools versus to this new technology and demonstrate improved identification of pay zones.