Production logging and flow profile interpretations are necessary to properly assess completion performance and interpret pressure buildup data in Chayvo Field. With a lateral reach in excess of 8 km, acquiring production logging data is difficult. Memory logging, with conventional production logging tools via coiled tubing and a hydraulic tractor, was employed. However, due to the wear experienced by the coil, high cost, and poor data quality at low flow rates, this technique was abandoned after initial logging efforts.

Development of a state-of-the-art electrically powered tractor, combined with new surface read out array mini-spinners and optical gas and array resistivity water holdup sensors, provided a viable logging alternative with a 40,000 ft cable specifically manufactured to avoid splice induced weakness. This new logging technology detects and measures stratified flow and lower flow rate fluid entry than conventional axial symmetric production logging tools in ERD well bores. The equipment has recorded production logs to a measured depth of 9,775 m at a true vertical depth of 2,613 m.

Comparison of cumulative flow rates from the array mini-spinner analysis to the logging-while-drilling derived cumulative permeability-thickness product has enabled the evaluation of the completion methodology. Based on the production log analysis, the new completion methodology appears to have restricted flow from the higher permeability intervals while permitting flow from lower permeability intervals. The methods used to plan and execute these production logging programs, and the integration of the interpretations into the pressure-transient analysis for the complex completions of multi-layered reservoirs, are discussed. Examples illustrating data quality and interpretation are provided.

You can access this article if you purchase or spend a download.