Recognizing Injected Sands Related to Deepwater Channel Complexes in Cores and Borehole Images from Angola Block 14 Wells
Injected sands are veins of sand that were remobilized after deposition. These sand veins commonly cut across otherwise impermeable shales and connect originally unconnected sand bodies, and thus can become very important components of reservoir models. Being able to recognize injected sands and predict their effect on connectivity enables field development with fewer wells, representing a huge cost savings in deepwater fields where individual well costs are high.
A comprehensive review of over 30 cored wells from Angola Block 14 reveals that injected sands are present in more than half of the cored intervals and can be recognized in borehole resistivity images as well. Injected sand veins range from less than 1 inch (2.5 cm) to more than 6 feet (2 m) thick in the cored examples. Injected sand networks can represent significant amounts of net pay (as much as 33’ (10 m)) in some wells. Cored examples of injected sands within some of the Angola Block 14 channel complexes show a variety of features, and demonstrate the range of reservoir quality of the injected sands relative to the deposited sands in the same channel complexes.
AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery