Flow Logging in Difficult Boreholes Making the Best of a Bad Deal

摘要

High-resolution flowmeters such as the heat-pulse and electromagnetic flowmeters are designed to operate in smooth-walled boreholes where flow-diverters (flexible disks or inflatable bladders) can efficiently block flow in the annulus outside of the probe's measurement section. However, field problems often involve large-diameter production wells with significant diameter variations, or there may be an open annulus outside of well screens in unconsolidated aquifers. Useful information can be obtained in such non-optimum flow logging environments by: 1) calibrating flow measurements to account for bypass around the flow measurement sections; 2) carefully selecting depth intervals where flow measurements are made; and 3) using fluid column logs obtained under ambient and pumping or injection conditions in the modeling of borehole flow response. Examples of such applications are illustrated for large-diameter production wells and long screened intervals in test boreholes at sites in Florida, Hawaii, and Kuwait.