Abstract
Organic-rich Kerogen of Lower Kimmeridgian to Upper Oxfordian age comprises of thinly laminated Kerogen with calcareous mudstone deposited in deep basinal environment. It has a consistent thickness of 50' in the entire study area with an average porosity of 4-6pu with nanodarcy permeability and is the main source for hydrocarbon plays in Kuwait. This rock sequence occurs at depths of 14000-15000 ft under HPHT conditions. Huge success of shale gas plays in North America has prompted the characterization of these source rocks to evaluate their resource play potential for the first time in Kuwait.
The Kerogen under study differs from proven US Shale gas fields in terms of comparatively higher TOC content, greater depth and much less in thickness (50ft) and in a Pre-salt setting. Hence these are challenging in terms of completion and production. These are inferred to be Type II Oil & Gas prone based on Vitrinite reflectance range from 0.98 to 1.17.
Tight rock analysis (TRA) and geo-mechanical studies of selected core samples within the study area provide critical input for Kerogen characterization. Kerogen is divisible into seven units based on electro-logs and log derived TOC and are correlatable with distinct facies assemblage, TRA derived petrophysical data and Geomechanical properties. Core derived UCS, Triaxial Compression test and Brazilian test based on lab results have brought out clear anisotropic behavior and enabled to bring out mechanical stratigraphy by integrating geomechanical properties and litho-facies variations within the Kerogen. This workflow has brought out the distinction of the carrier beds in alternations with Kerogen-rich layers as well as planned well trajectory along the carrier bed in the central part of Kerogen. Lastly, proppant compatibility tests combined with Young's Modulus provide valuable input for planning horizontal wells and subsequent hydro-frac design for completion.
