Wireline Sand-Detection Tool Locates, Quantifies Downhole Sand Production

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 198566, “Locating and Quantifying Downhole Sand Production With Wireline Sand-Detection Tool and Examples of Application in Wells Offshore Caspian Sea,” by Andrey Timonin, Schlumberger, and Eldar Mollaniyazov, Dragon Oil, prepared for the 2019 SPE Gas and Oil Technology Showcase and Conference, Dubai, 21-23 October. The paper has not been peer reviewed. Most of the wells in the Dzheitune (Lam) field in the Caspian Sea were completed with dual tubing. Depletion in reservoir pressure caused formation failure in the A sand reservoir, and wells producing from this formation began to produce sand. Field examples presented in the complete paper describe principles of data acquisition with a sand-detection tool when run in combination with a production logging string and results of logging in slightly deviated wells completed with sand screens. Comparison of multiphase-inflow profiles with sources of sand production showed that most sand was produced through eroded intervals in the sand screens. Introduction Most Lam wells were completed with 9.625-in. casing and 7-in. liner across the reservoir section. The A sand reservoir, located at depths between approximately 1500 and 1800 m, and the CH sand reservoir, located below 2000 m, are produced separately by using dual-string tubing to avoid crossflow from the high-pressure CH reservoir into the low-pressure A reservoir. When wells in the A reservoir began to produce sand, the operator had to change the completion strategy for newly drilled wells and had to recomplete some old wells by pulling out of hole dual-string completions and running in hole single tubing with sand screens across existing perforations. The top of sand accumulation in the annulus was identified with a slim sonic tool that measures cement-bond-log and variable-density-log data. This change in completion strategy helped prevent sand production to the surface, but, eventually, several wells completed with sand screens across the A reservoir began to produce sand on the surface, damaging production facilities and plugging separators, which had to be cleaned periodically. To identify the source of sand production downhole and to verify the integrity of sand screens, a sand-detection tool was run on wireline in a few such wells.