Fullwave Sonic Analysis: New Methodologies for Characterizing Near-Wellbore Reservoir Properties

Abstract

Full waveform sonic (FWS) data is a measure of amplitude as a function of time. It is an important data source for formation evaluation and reservoir characterization. Determination of Poisson’s ratio, porosity, lithology, borehole geomechanics, near-wellbore velocities, fractures, fluid types, and permeability are some of the areas of application of FWS data. This paper discusses two new methodologies that use FWS data for reservoir characterization. First, we discuss a fracture analysis workflow that utilizes a sequential, Windows-based sampling and interpretation approach to achieve a depth of investigation of up to 1.50 meters into the formation. This is a remarkable improvement over image logs. Second, an enhanced fluid analysis approach that is based on a higher-order normalized differential energy methodology is discussed. Higher-order normalized differential energy estimates from low frequency Stoneley waves show that energy loss varies with offset. Additionally, light hydrocarbons behave differently from water on 2nd-order normalized differential energy computations. This suggests a potential method for formation fluid differentiation in the near-wellbore region.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018