In gas shales the completion process can be described as changing the source rock into productive reservoir rock with the application of a fracture treatment. Successful shale gas operators have been applying technology to shift to drilling fewer wells and getting better coverage of the rock volume with fracture treatments. Overall this approach gets better results with fewer resources than the historic approaches used on tight gas plays. This tactic, however, has led to significant changes in the way work is done in the field. Now operators are consolidating operations from numerous sites into a few larger pads with many wells drilled from the same surface location. This environmentally sensitive approach has yielded far less surface disturbance but created some other consequences as well. The resulting close surface and subsurface well proximity has resulted in new safety, technical and operational challenges. A large part of the completions engineering effort is focused on solving both surface and subsurface issues related to proximity. Apache has recently completed a pad of 16 wells with 274 completed intervals in the Horn River area.

In this paper both surface and subsurface interference issues will be discussed as well as the plans for coping with the interference. Examples of interference situations and recorded downhole pressure communication from the project will be discussed with a focus on how new processes and automated tools such as the newly developed surface safety protocols and a subsurface proximity calculator enhances the planning of operations and the safety of the site.

Apache has developed a subsurface completions proximity calculator to enhance the ability to plan and adjust downhole operations in an environment that may change day to day or hour to hour. The tool collects all the subsurface data and instantly gives a picture of downhole interactions and supports planning to reduce risk. The avoidance of exposure of high pressure operations to other critical lower pressure operations, such as fraccing proximate to drilling or completion interventions, will be outlined.

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