Fracture corridors are sub-vertical tabular bodies of fracture swarms which traverse vertically entire reservoir thickness and extend laterally for several tens to hundreds of meters. Fracture corridors are genetically related to faults or incipient faults and are the main building blocks of fracture systems in many reservoirs in the Middle East. Fracture corridors are best identified from horizontal borehole image logs, but the number of wells with image logs is often limited and it is necessary to use indirect means to detect fracture corridors. Fracture corridors manifest themselves as spikes in horizontal well openhole logs. In fields with water injection, fracture corridors can be identified as water saturation spikes with no corresponding change in porosity. Fracture corridors with cemented walls have bulk density spikes. In many cases fracture corridors are associated with caliper enlargement and lost circulation. In some Middle East carbonate reservoirs fracture corridors appear as gamma ray spikes.

Fracture corridors are not the only cause of openhole log spikes. It is necessary to validate and determine fracture corridor signatures in openhole logs by comparing open hole and image logs first. If a diagnostic signature can be recognized, openhole logs, in combination with lost circulation data, can be used to locate fracture corridors in other horizontal wells with no image logs. If there are a sufficient number of image logs from horizontal wells with fracture corridors, it is possible to correlate spikes with actual fracture corridors and determine the probability to correctly identify a fracture corridor.

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