Natural Fractures in the Northeast British Columbia Foothills, Canada

Mendez, Armando, BP Canada Energy, Calgary, AB

During the last years, BP Canada Energy was involved with exploration and early devel­opment activities in British Columbia, with a good rate of success. A few number of medi­um size sour gas fields were discovered in Triassic and Late Carboniferous carbonate reser­voirs. Dolomite is the predominant rock-type and is usually tight just enough to grant gas storage but not enough to provide good rate. Faulted anticlines with complex frontlimbs is the typical trap. En-echelon features is often observed on map views.

Presence of natural fractures has been established by means of conventional core, side wall cores, wireline logs, image logs as well as limited spinner log data. PBU data suggests Kh that can only be explained by presence these fractures.

Understanding of fracturing in these reservoirs is important for well planning and ulti­mate recovery in this area. Special effort has been put towards well targeting in order to opti­mize reservoir intersection and well angle across the reservoir in relation to natural fractur­ing. Failure to do so would imply to have a very poor performing well.

A comprehensive study was carried out during the last two years to characterize frac­tures in these fields. FMI data was highly valued given its presence in most of the wells and the quality of images. Detailed interpretation of these images was performed in all wells to grant consistency and quality. A predominant fracture orientation across the structures was identified. Distinctive high density of fractures in axial planes or at the leading edge of the structures was not necessarily established.

Results of this study will be shared in this paper and actual use of understanding in well targeting will be presented.