Integration of outcrop and subsurface data during the development of a naturally fractured Eocene carbonate reservoir at the East Ras Budran concession, Gulf of Suez, Egypt

Abstract

The East Ras Budran Concession is located in the eastern rift shoulder of the Gulf of Suez. Syn- and pre-rift rocks are exposed in the north and east of the concession, and the Markha alluvial plain covers the SW. The Markha plain occupies the hanging wall of a large extensional fault which preserves most of the pre-rift stratigraphic sequence and >3500 m of syn-rift strata. Vertical wells drilled in 1999 indicated the presence of a >200 m oil column in low-porosity naturally fractured limestone beds of the Eocene Darat and Thebes formations. Outcrop, borehole image and core data define NW, WNW, N, NE, and ENE steeply dipping fracture sets. Borehole breakouts and drilling-induced fractures show that the minimum horizontal stress is aligned NNE to NE, so the NW and WNW fractures should be open in the subsurface. Using this structural picture, a near-horizontal well of 300 m length was drilled into the Darat in a NE direction. During testing, the well flowed at a rate of 1900 barrels of oil per day with no water. Future development of the field includes drilling similarly oriented wells with longer horizontal sections.

Advances in the study of naturally fractured hydrocarbon reservoirs: a broad integrated interdisciplinary applied topic

“…Examples of petroleum-industry-based case studies of fractured reservoirs in both sedimentary and crystalline rocks are also presented, including: two examples of industry case studies of naturally fractured crystalline basement reservoirs (Murray & Montgomery 2012;Slightam 2012); four case studies of carbonate reservoirs (Bosworth et al 2012;Saoudi et al 2012;Ward et al 2012;Delorme et al 2013); and one naturally fractured tight-gas sandstone reservoir (Sonntag et al 2012).…”

“…These include borehole data derived from wireline logs, especially image logs including FMI TM and FMS TM resistivity images (e.g. Bosworth et al 2012;Delorme et al 2013;Saoudi et al 2012Ward et al 2012) and sonic acoustic images (e.g. Prioul & Jocker 2009;Slightam 2012), VSP (vertical seismic profile; e.g.…”

“…Emsley et al 2007;Slightam 2012), core analysis (e.g. Bosworth et al 2012;Sonntag et al 2012;Sagi et al 2013) and drill cuttings (Ortega & Aguilera 2014). Geologically appropriate outcrop analogues are also frequently studied as proxies for subsurface fracture networks (e.g.…”

“…Geologically appropriate outcrop analogues are also frequently studied as proxies for subsurface fracture networks (e.g. Bosworth et al 2012;Rotevatn & Bastesen 2012;Slightam 2012;Sonntag et al 2012;Seers & Hodgetts 2013), often in combination with other subsurface geophysical data. Numerical modelling including the finite element method (e.g.…”

“…6 study of core, the study of outcrop analogues and numerical modelling may be integrated by employing scaling and statistical techniques to produce the best possible multiscale picture of the fracture network in the reservoir (e.g. Bertotti et al 2007b;Hall et al 2007;Prioul & Jocker 2009;Bosworth et al 2012). Fracture networks characterized using subsurface techniques, outcrop analogues and geomechanical modelling can be used in both deterministic reservoir models and/or in statistical approaches in which fracture parameters derived from these multiple methods are used to populate stochastic reservoir models for use in fluid flow simulations.…”