Determination of Formation Density Through RC Rods in Iron Ore Environments

Abstract

Logging through drill rods and casing is a well-known challenge in the coal, oil and gas industries, and several techniques have been developed to obtain open-hole values using open-hole tools in cased-hole (C-thru). Due to the differences between conventional open-hole and iron ore environments and practices, simply applying the same methods can result in spurious data and unreliable findings.

A revised tool design together with an improvement upon the standard oil and gas technique through single wall rods was required to ensure accurate results. Development of an appropriate compensation algorithm and response through Reverse Circulation (RC) rods was determined where multiple walls of steel and gaps of fluid and air separate the tool from the target formation.