Stimulation of the Upper Devonian Benson Formation of Central West Virginia has lead to the use of various types of treatments. The following is an investigation of one of the more recent techniques, Foam/Nitrogen Fracturing, as it compares to the conventional Water Frac methods.

The Benson is a shallow water turbodite deposit with thicknesses variable up to 30 feet. It is a brown siltstone which characteristically becomes commercially productive only after stimulation. Over the past three years stimulation of Union Drilling Benson wells in Upshur and Barbour Counties has been exclusively Foam Frac or Water Frac, with few exceptions. Foam Fracs were used initially for three reasons: (1) to keep large volumes of water out of the formation in order to prevent clay swelling, (2) to aid in well clean-up, (3) to allow better sand placement through increased carrying quality of foamed Nitrogen. The ultimate goal of the Foam treatment is to increase gas flow from the wells.

Methods of investigation include records kept of (1) volumes of water used for treatments, (2) cleanup and service rig time and efficiency (3) open flows from foam frac and water frac treated wells, an indication of the sand placement abilities. Conclusions based on open flow results indicate that lower volumes of water, quicker well clean-up, and improved sand placement are desirable for the Benson Formation.

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