Sedimentology from Wellbore to 3-D Reservoir with High-Definition Borehole Images in both Water-Based and Oil-Based Muds

Recently two near-offset wells were drilled at the Catoosa, Oklahoma USA. The first well was drilled vertically with WBM and logged with an industry-standard high-definition microresistivity imager. The second well was drilled at 25 degrees deviation with OBM and logged with a prototype of a new-generation high-definition OBM-adapted imager. Significant specifications of the new OBM-adapted imager include 192 sensors providing 0.23 in vertical resolution and 98% coverage in 8-in borehole. A quick comparison of the various images acquired validates the quality of the new-generation high-definition OBM-adapted images. The OBM-adapted imager is able to deliver images that are equal to or better than an industry-standard imager run in a WBM environment. The high-definition borehole microresistivity images are increasingly well-established as key input to 3D modelling workflows in clastic reservoirs drilled with water-based fluids (WBM), providing structural and sedimentological control in the near-wellbore space with a much higher degree of confidence than seismic. We focus on demonstrating the use of such images in a workflow for 3D structural and facies modelling. The workflow consists of the several steps to enhance field models based on 3D seismic data, or to produce standalone models that do not depend on the availability of seismic data.