Enhanced, Low-Resistivity Pay, Reservoir Exploration and Delineation with the Latest Multicomponent Induction Technology Integrated with NMR, Nuclear, and Borehole Image asurements

摘要

The first multicomponent induction instrument available to thernindustry provides vertical and horizontal resistivity data for anrnimproved delineation and evaluation of low resistivity, lowrncontrast pay zones frequently encountered in offshorernhydrocarbon exploration. This instrument surveys thernformation in three dimensions with multicomponentrntransmitter-receiver induction coil arrays to derive the truernhorizontal and vertical formation resistivities. The horizontalrnand vertical resistivities obtained from the multicomponentrninduction measurements can be interpreted jointly withrnstandard array induction and image log interpretation data.rnConventional array induction data assists 3DEX TMrnresistivity data interpretation by removing deeper invasionrneffects through 2D inversion methods. A realistic examplernderived from field data including anisotropic sandsrndemonstrates how vertical and horizontal resistivity from arnmulticomponent induction instrument can be jointlyrninterpreted with NMR data to provide additional reservoirrninformation. A second field data example demonstrates howrnnew petrophysical evaluation methods utilizing the newrnmulticomponent induction instrument’s resistivity anisotropyrndata improve the economic evaluation of low resistivity, lowrnutilizing vertical and horizontal resistivity, nuclear, and NMRrndata yields a more accurate and reliable formation waterrnsaturation evaluation in anisotropic thinly bedded, laminatedrnsand shale sequences.rnConventional induction logging instruments have therntransmitter and receiver array orientation aligned parallel tornthe tool and borehole axis. Therefore, in vertical wellsrnhydrocarbon-filled sand shale sequences conventionalrninduction instruments measure a resistivity, which is greatlyrnbiased towards the low resistivity of shales. This results fromrnthe dominant current flow for the source/receiverrnconfiguration being horizontal and occurring mainly throughrnthe low resistivity shales: thus, horizontal resistivity isrnmeasured. This can lead to an underestimation of the sandrnlaminae oil saturation. The multicomponent transmitter-receiverrninduction instrument configuration provides directrnmeasurements to derive both horizontal and verticalrnresistivities. These resistivities allow an improvedrnpetrophysical evaluation of hydrocarbon-bearing, thinlyrnbedded shaly sand formations.rnField examples demonstrate the benefits of jointrninterpretation of multicomponent data with image logs tornproperly model and interpret resistivity anisotropy in zonesrnwith resistive streaks and variable laminated formationrnstructures.