Eastern Section Meeting

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Bit Type Analysis and Drilling Concerns through the Top Hole Formations of the Utica Shale Play

Abstract

With the advent of horizontal drilling and hydraulic fracturing techniques, unconventional gas shale have become increasingly sought after for oil and gas production in North America. The Utica Shale play in Eastern Ohio, northern West Virginia and western Pennsylvania has experienced considerable growth in recent years. As a previously relatively ignored region in the oil and gas industry, the formations drilled through the top hole Utica present unique drilling problems not present in other plays. Various approaches to achieving a consistent and cost effective well plan have been attempted, including changes drilling parameters, casing design, drilling fluids and drill bit types. This study attempts to quantify the advantages, if any, of the various drill bit types used. The formations drilled through a typical Utica Shale well include consolidated and unconsolidated sandstones, limestone, dolomites, shale and evaporites. The two most common bit types used in the Utica shale top holes are percussion bits and roller-cone bits. While variations within these categories exist to address different formation properties, a general held rule of thumb is that percussion bits are best designed for hard, brittle formations such as consolidated sandstones. limestone, and dolomites: while roller-cone bits are best designed for soft to medium formations such as shale, softer limestone and dolomite, and unconsolidated sandstones. This study looks at the rate of penetration and bit failures to find if any significant variations exist overall and/or through specific formations.