Characterizing Fracture Corridors for a Large Carbonate Field of Kuwait by Integrating Borehole Data with the 3-D Surface Seismic
Developing fractured carbonate reservoirs has always been demanding for the geoscientists of the oil industry. Fracture corridors are thought to be the main features controlling fluid movements in these reservoirs. Locating these corridors and determining their vertical and lateral extents are the main requirements by those involved in planning locations for new producer and injector wells in any field of interest. Information on fracture corridors can further be used to construct comprehensive DFN(Discrete Fracture Network) models for reservoirs with a higher degree of certainty.
This paper discusses an innovative workflow to locate fracture corridors and estimate their dimensions. The workflow is centered around the Fracture Cluster Mapping (FCM) technique, which facilitates integration of borehole scale data, geomechanics, and tectonics with the 3D surface seismic. Surface-seismic data processing is optimized for it to be used for fracture clusters / corridors detection. Having a good understanding of fractures’ pattern in the field and optimally processed 3D seismic data, Ant Tracker (essential part of FCM for automatic extraction of discontinuities ) is run on the seismic cube and parameters are conditioned to highlight fracture clusters / corridors of certain orientations related to tectonic history.
The workflow was tested on the exploration area for the Jurassic carbonates of low porosity, low permeability and about 3000 ft thickness in Kuwait. The FCM technique highlighted on the seismic cube fracture corridors of varying density, orientation, vertical and horizontal extents across the study area. At the well locations (existing ones and newly drilled ones), the predicted fracture corridors matched reasonably well with the fracture orientation and density interpreted for each well from cores and borehole images.
The approach has a great value in deciding locations for new wells, planning well trajectories (to avoid or intersect a certain type of fracture network), and production predictions. It is important to use this approach in preparing comprehensive DFN models. It is more important in the areas where deeper depths and sparse well data have added more uncertainty in fracture prediction. The approach was developed and tested first time ever for few fields in Kuwait.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009