The Lower Huron Shale can take claim as one of the earliest discovered sources of natural gas. As with all the shales though, extracting its reserves has been the challenge. To start, the physical properties of shale are not the same as typical sandstones, limestone, and siltstones that are targeted to produce natural gas. Along with this, the mechanisms for which the hydrocarbons are stored in place and transported are unique as well.

Shale is notorious for having ultra-low permeability (μD) and because of this, the primary storage and transport of hydrocarbons comes through the series of natural fracture networks within the shale. Fracturing the shale then becomes a search for the natural fracture network that is holding the hydrocarbons.

After drilling is completed, the question becomes exactly how do we fracture this well to achieve the best results? There are several ways to stimulate the wells that have been drilled in the Lower Huron. They range from straight nitrogen stimulation to varying quality foam stimulations. These two main methods of fracturing can then be broken down into many different style stimulations by changing rates, foam qualities, sand volumes and nitrogen volumes.

A couple of things to look at when designing a stimulation job is depth, field of play, thickness of the zone, and its gamma ray reading on the log. This paper will discuss fracture styles and which ones seem to perform better in wells given certain characteristics and what might be changed to produce the best results.

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