This book contains seventeen papers arising from a Petroleum Group conference in November 2004, a somewhat lengthy gestation but ultimately worth while. The content is subdivided into four sections.
The first, outcrop studies, comprises papers on economically critical fold-related fracturing in the Asmari reservoirs of the Zagros Mountains, transient fracture permeability and diagenetic resealing in the Dent Fault (UK) and factors affecting the potentially very variable transmissibility of relay ramps in sandstones based on data from Utah. Notable in the value of outcrop studies is the detail and insights now available from satellite imagery.
The second, geophysics, includes a discussion on fracture compliance (unfortunately without saying what it is!), a useful reminder of the value of VSP data in bridging the seismic/well-scale gap, and some laboratory data with potential to improve the use of acoustic emission in the engineering geology of fractured rock. The value of the latter, if any, to production monitoring of fluid depletion is unclear.
The third, numerical and analogue modelling studies, deals with estimating the complicating effects of concurrent diagenetic stiffening of matrix blocks during fracture, the correlation of variable geometry fracture networks with well test response, the use of elastic dislocation theory in the prediction of lower-order fracture orientation and an experimental study of fracture localization by dip-domain boundaries in buckle folds. All are topics requiring familiarity by those at the geology/reservoir engineering interface.
The fourth, reservoir case studies, is the longest and arguably the best part of the book, giving not only hard data but valuable insight into the commonly recursive processes of evaluation. Two cases deal with chalk fields of the North Sea where fractures govern economics in reservoirs with high matrix porosity and low matrix permeability. Other papers include the pre-development fracture modelling in the gigantic West Shetland Clair Field, studies in both clastic and carbonate reservoirs from Oman and an account of fracture distribution in folded thrust sheets from western Canada. All stress the multidisciplinary requirements for evaluation success; indeed there is no single-author article in the whole book.
Although a ‘slim’ volume, the book is fair value for money and especially at discounted price may attract personal purchases from those engaged in the management of fractured reservoirs. Libraries should certainly endeavour to stock it. Particularly commendable is that the majority of the papers are informative and well-written and all are concise. Less so is the absence of an overview article giving introduction and literature guide to many aspects not covered in the conference such as artificial fracturing for well stimulation, karst fracture reservoirs with negligible matrix porosity in palaeogeomorphic traps, cleat fractures controlling coalbed methane economics, dense polygonal faulting as a determinant on production potential and shear wave polarization for evaluation of fracture orientation. An annotated global listing of major fractured reservoir plays would also have helped to augment the value of the book to those seeking the general introduction that might be implied by the title.
