Unravelling North Oman Fractured Reservoirs Using a New Integrated Fracture Characterisation and Modelling Tool

Pascal D. Richard and George Warrlich
Study Center, Petroleum Development Oman, Muscat, Oman

A significant proportion of Petroleum Development Oman (PDO) future production resides in heavy-oil, fractured carbonate Shuaiba reservoirs. The development of these reservoirs is largely dependent on the feasibility of steam assisted gas oil gravity drainage (SAGOGD). The success of this recovery method relies on a well connected fracture network. In order to assess the feasibility of this development strategy, a series of fracture characterisation and modelling studies had to be carried out. One key enabler for these studies is the new software technology, SVS-Fracture Solutions, developed by the Carbonate Team, in Shell EP-Research.

The key pillar of the SVS workflow is a detailed fracture characterisation, captured in a series of conceptual models, which reflect the range of the subsurface uncertainties to be expected. SVS allows constraining these models by integrating data from various sources (wells, seismic, petrophysics, geomechanics, outcrops, etc), in combination with field kinematic structural evolution, analogue neighbouring fields and the regional understanding established by PDO’s long-term activities in the area. Once the conceptual models have been developed, these can be transformed into discrete fracture models with attached attributes (such as permeability anisotropy, fracture spacing etc). These models can be transformed into reservoir simulation properties and up-scaled in simulation grids. Simulations were run in dual porosity dual permeability thermal mode.

This paper illustrates the added value of a consistent fracture characterisation approach to assess the development strategy at regional scale. We place particular emphasis on demonstrating the impact of data integration, borehole image analysis, geometrical constraints as well as the use of web based analogue model database to help constrain the structural understanding of the fields.

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