Flow Unit Characterization aided by Quantified Secondary Porosity Result from High Resolution LWD Images in Heterogeneous Carbonate Reservoir; A Novel Approach

Abstract

Heera field is one of the most prolific fields in the Mumbai offshore basin in India. The field belongs to one of the six tectonic blocks (Heera-Panna-Basseinn block) of Mumbai offshore basin. Carbonates are by far the major contributor in terms of hydrocarbon production in this field. Presence of Vugs, Fractures and Solution enhanced features makes it a real challenging job to understand the porosity distribution within this reservoir. Characterizing and quantifying the complex secondary porosity profile and identifying different flow unit is immensely important for production optimization and appropriate completion design. The challenge of understanding the porosity heterogeneity of Carbonate reservoir further increases where critical borehole condition averts the possibility of running high resolution Wireline imaging tool. A novel approach has been taken for the first time in this field to quantify and characterize the secondary porosity distribution and permeability prediction from high resolution LWD Resistivity Image. Good quality LWD Resistivity Image has been processed using advance processing software and a quantified result of secondary porosity spectrum was obtained using robust algorithm. This quantified secondary porosity result is further utilized to characterize the different high resolution flow unit throughout the borehole. This paper illustrates a case study where quantified result of secondary porosity and estimated permeability has been derived using LWD resistivity image in conjunction with the openhole measurements.Micro-facies variation in terms of fluid flow characterization, size & nature of vugs and laminated beds has been established. This will lead to accurate completion designing for production optimization. The result was then validated with the secondary porosity derived from the high resolution Wireline Image and Mobility data from samplingtool.In a nutshell, this work opens a new regime of application of LWD image in terms of advance Geological and Petrophysical interpretation in addition to its other benefits like borehole stability and Geosteering capability.