Structural Permeability Assessment Combining Three Field-Scale Models in the Wayang Windu Geothermal Field, West Java, Indonesia

Abstract:

The Wayang Windu Geothermal Field is situated on the flanks of a now quiescent volcano within the Southern Volcanic Complex on Java Island. The field is surrounded by a number of high topography geothermal systems. It has been in operation since 2000 and currently generates ~230 MWe for the Java-Bali grid system.

This talk presents the methodology to assess the subsurface permeability distribution of the Wayang Windu Field. The study integrates three field-scale models derived from a broad multidisciplinary set of data:

1)      A geological model provides the structural framework, lithology and reservoir properties;

2)      A 3D geomechanical model provides the magnitudes and orientations of reservoir stresses, pore pressure evolution and rock mechanical properties;

3)      A discrete fracture network (DFN) model describes the fracture characterisation and distribution.

When coupled together these models spatially assess the structural fracture permeability of the reservoir and delineate potential areas that may be associated with fluid pathways to optimally locate future well targets. Over the reservoir structure, the predominant stress sensitive fracture intensities appear to align to form permeable fracture corridors or “hydro-structures”. The study results will be used to guide development drilling and fracture treatments that can improve output from the Wayang Windu Field.

Presenter: Adrian White, Geomechanics Team Leader Australasia, Baker Hughes Reservoir Development Services

Adrian received his Ph. D. in Structural and Petroleum Geology from the University of Durham in 2002. In January 2005 he joined GeoMechanics International (purchased by Baker Hughes in 2008) and has been involved in training and consulting throughout the Asia-Pacific region ever since. Adrian has experience in constructing geomechanical models and pore pressure prediction from wireline log and seismic data. He has successfully implemented these processes in field and reservoir development and characterisation, fracture and fault stability, wellbore stability, drilling strategies and reservoir completion throughout Australasia and SE Asia. He has recently worked on studies in Indonesia, Vietnam, Malaysia, New Zealand and Australia on geothermal systems, extended-reach drilling, real-time post-mortem assessments and fault reactivation and stability