An Innovated Approach for History Matching by Reliable Fracture Modeling - Case Study of NKJ Gas Field

Abstract

Introduction: The North Kuwait Jurassic Complex (NKJC) is composed of six fields and situated in the Northern part of Kuwait (Figure 1). The field is characterized by dual porosity/permeability in deep HP/HT conditions, with wide variety of hydrocarbon fluids ranging from volatile oil to gas condensate. The primary recovery mechanism and the recovery efficiency strongly rely on fractures. Therefore, reliable and calibrated fracture model is required in getting a representative dynamic model. Using a wide range of 2D/3D seismic, geometrical and petrophysical attributes, a hybrid natural fractured reservoir static geomodel, made of Discrete Fracture Network (DFN) and Implict Fracture model (IFM), has enabled a reasonable 3D representation of three sets of fractures, identified based on well and seismic data:Fracture corridors associated to geophysically interpreted faults;Medium scale layer bound geomechanically controlled fractures; andFolding related fractures. The new hybrid fracture model was calibrated using PLT, MDT and PBU data from more than 60 wells drilled in the reservoir. This paper demonstrates how a calibrated hybrid fracture model has shortened the process of the history match significantly, which required only very small adjustments/alterations to the initial static model. The uncertainty and the challenges faced while calibrating the model were addressed, together with the highly sensitive parameters that were adjusted to match the dynamic data. Succeeding a smooth and timely history match resulted in significant CPU time gain, and an optimized well count that went into the Asset Action Plan.