Sustaining long-term well production in deep gas wells can exhibit unique challenges in shaly sands. The wells can be vertical or slanted gas producers and completed with stand-alone screens. The challenges were to quantify zonal contributions, detect smaller water entries on these high-temperature deep gas wells where reservoir heterogeneity with different depletion layers can result in strong crossflow, and evaluate the existing sand formation behind the screen to avoid restricting the wells' productivity.

This paper describes an integrated approach taken to overcome these challenges with three field examples. A multiphase production logging tool was run to measure the water flow together with the gas contributions across the stand-alone screens on these wells. A pulsed neutron logging tool was run to identify the small amount of water by using a water flow log model. Ton assess and evaluate the conditions of sand behind the screens, two independent logging techniques were implemented: silica activation and carbon-oxygen inelastic silicon yield techniques.

A combination of pre-job planning, an optimized logging program, and proactive real-time monitoring allowed a safe logging operation by drastically minimizing the time exposed by the tool downhole in a high-temperature environment. Early monitoring of water production is important to achieve optimal well productivity and reduce the possibility of the hydrate formation obstructing the flow lines. The source of sand production and the quality of the packing behind the screen were also evaluated. This best practice was established in the field and will greatly improve well deliverability and maximize gas field production.