Methods of Generating Synthetic Acoustic Logs from Resistivity Logs for Gas-Hydrate Bearing Sediments

摘要

Methods of predicting acoustic logs from resistivity logs for hydrate-bearing sediments are presented. Modified time average equations derived from the weighted equation provide a means of relating the velocity of the sediment to the resistivity of the sediment. These methods can be used to transform resistiv-ity logs into acoustic logs with or without using the gas hydrate concentration in the pore space. All the parameters except the unconsolidation upnstants, necessary for the prediction of acoustic log from resistivity log, man be estimated from a cross plot of resistivity versus porosity values. Unconsolidation constants in equations may be assumed without rendering significant errors in the prediction. These methods were applied to the acoustic and resistivity logs acquired at the Mallik 2L-38 gas hydrate research well drilled at the Mackenzie Delta, northern Canada. The results indicate that the proposed method is simple and accurate.