Rock Fabric Influence on Hydraulic Fracture Propagation
S. Stanchits, J. Desroches, J. Burghardt, A. Surdi and N. Whitney
Event name: 77th EAGE Conference and Exhibition 2015
Session: Geomechanics and Hydraulic Fracturing
Publication date: 01 June 2015
Info: Extended abstract, PDF ( 1.21Mb )
Price: € 20
Hydraulic fracturing is crucial for hydrocarbon production from unconventional reservoirs. However, often the efficiency of the completion treatment is poor, which is considered to be a result of lateral heterogeneity in reservoir quality. To investigate the influence of rock fabric on a near-wellbore geometry, we conducted two laboratory tests on Niobrara outcrop shale blocks stressed in true-triaxial frames. The Acoustic Emission (AE) technique monitored hydraulic fracture initiation and propagation, while post-test measurements revealed the fracture shape and aperture. In both tests, AE analysis indicated hydraulic fracture initiation prior to the maximum wellbore pressure (breakdown) and asymmetrical fracture propagation. Post-test analysis demonstrated that AE results corresponded well with post-mortem surface maps. The first test revealed a crossing of weak bedding planes accompanied by fluid leak-off. In the second test, the hydraulic fracture was arrested at the boundary of a calcite-filled fracture. In addition, fracture aperture mapping indicated narrow aperture in that area. We conclude that near-wellbore planes of weakness, such as mineralized natural fractures, can result in hydraulic fracture propagation arrest, or in poor fracture geometries with limited aperture that, in turn, could lead to high treating pressures, low fracture conductivity, restricted proppant delivery and decreased production.