Understanding Unconventional Potential of an Early Kimmeridgian Calcareous Mudstone

Abstract

The of focus of this study is an organic-rich calcareous mudstone formation of early Kimmeridgian age; it is believed to be a promising unconventional resource in the Jafurah sub-basin. The formation covers a large area in the basin, has moderate total organic content (TOC) values, and has long been recognized as part of the source-rock system that provides conventional hydrocarbons trapped in shallow-marine carbonates within the giant oil fields of Saudi Arabia. Preliminary results from detailed (centimeter scale) core logging and description of five wells located within the Jafurah sub-basin show highly variable lithofacies and facies associations. Selected samples representing each lithofacies will be examined by integration of a broad range of analytical techniques, including; optical microscopy using ultra-thin sections, Rock-Eval pyrolysis, stable carbon and oxygen isotopes (δ13C and δ18O), x-ray fluorescence, x-ray diffractometry, Quantitative Evaluation of Materials by Scanning Electron Microscopy (QEMSCAN), and porosity/permeability characterizations from the micro- to nano-scale using scanning electron microscopy (SEM), Micro CT scan, mercury injection capillary pressure, and focused ion-beam SEM. The ultimate goals of this study are to produce a detailed facies analysis, a high-resolution chemostratigraphic framewors, sequence stratigraphic interpretations, and reservoir quality evaluations. This research will thus provide an integrated model for the unconventional exploration and exploitation that will help to identify exploration fairways and to design selective drilling, completion, and stimulation strategies in the future.

AAPG Datapages/Search and Discovery Article #90351 © 2019 AAPG Foundation 2019 Grants-in-Aid Projects