Synthetic Well Logging: The Effects of Dolomitization on Wireline Logs

Abstract

The Lower Mississippian Fort Payne Formation is a calcareous and siliciclastic-rich unit that stretches from Tennessee to Kentucky in thicknesses ranging from 100 ft. to 275 ft. thick. It presents an extensive amount of relithification where dolomite diagenesis has occurred. Dolomite replacement occurs in carbonate systems during diagenesis. Groundwater may contain dissolved solids (e.g. magnesium) that facilitate replacement of calcite with dolomite.

The purpose of the research is to evaluate how a carbonate system will appear if it is only limestone or a combination of limestone/dolostone or limestone/dolostone/shale. Wireline logging is a common geophysical method used by the petroleum industry and many sub-surface researchers to obtain lithology, resistivity, fluid properties, and more; however in this study, synthetic well logging is focused on the geomechanical properties, porosity, and mineral composition of known Fort Payne facies. To better decipher what was primary deposition and what are now the secondary structures, synthesized acoustic and density-neutron wireline logs are used to demonstrate expected feedback from a diagenetic carbonate system.