Structural Analysis for Fracture Optimization

Abstract

In this paper we will present an innovative multi-disciplinary workflow based on a structural modeling technique, ‘Complex Geometry fields’, that enables a geologist to generate attribute predictors for fracture densities such as detailed bedding geometry, curvature, dip and strain across an asset or basin. We will explain and demonstrate how this technique can be used to benefit the operators of unconventional assets in the following way; the attribute predictors can be used to ‘map out’ an estimate of the fracture density distributions in three dimensions in a study area which, in turn, can be used to optimally orient laterals well sections. The orientation of the laterals well sections with respect to the best estimate of the natural fracture orientation trends is thought to be of critical importance when designing completions and induced hydraulic fracture operations that ultimately control the flow of hydrocarbons into the well bore and thence to surface facilities. The computations to generate these geometry fields and predictors are based on the geometry of interpreted surfaces using established kinematic models such as vertical/oblique shear and flexural slip that account for compressional or extensional tectonic regimes and also the geo-mechanical lithological competency of the target formations. A good understanding of the structural components of the basin architecture are critical not just for hydrocarbon maturity but also in terms of understanding the behavior or natural and induced fracturing and faulting. After the structural geology attributes have been computed this information is then combined with and calibrated to other useful information such as 3D azimuthal seismic attributes or petrophysical and geomechanical observations derived from well locations to give the highest degree of accuracy with respect to predicting the gross distribution of the regional stress state and therefore understanding the associated development of fracture densities. The applications of creating a multi-disciplinary 3D numerical model of the subsurface that is enriched with this regional structural geology component are wide reaching but really benefits completion and hydraulic fracturing design as well as full field well planning strategies and the associated logistics because you have generated a high fidelity prediction of the subsurface across your entire asset.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015