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Abstract
Multiple stage hydraulic fracturing is a key technology driving the development of unconventional resources in North America. This technique began in the Barnett shale and its application has opened the door for the successful development of nearly every shale play in the world, including the Eagle Ford shale. Given the relatively new application of this technique, and the number of fracture treatments completed, initial fracture treatment designs in a given play are often transferred from other North American shale plays to serve as baseline treatments. Given the rapid pace of development in a new play, as well as the desire to get to a standardized completion program, many operators continue to use these baseline designs and fail to evaluate current designs to develop more optimal treatments.

This paper will discuss the successful evolution of hydraulic fracture designs in the Eagle Ford shale from one operator’s perspective. It will detail the development from the traditional low conductivity slick water fracture treatments used initially in the play, to the use of higher conductivity hybrid fracture designs. In addition to detailing the theory and workflow of these design changes, this paper will also evaluate production data from multiple wells and evaluate production results for the hydraulic fracture designs. Discussion of enhanced conductivity will be presented along with the economic benefit of these changes.

Those working the Eagle Ford shale can directly apply the principles presented in this paper to enhance the productivity and economics of their completions. In addition, engineers working other resource developments can use the principles from this paper to compare their current fracture design methodology and develop best practice approaches for hydraulic fracture design optimization in their respective plays.

Introduction
Unconventional resources require fracture stimulation to achieve hydrocarbon production at economic rates, and advancements in hydraulic fracturing techniques and horizontal drilling in the past fifteen years have greatly aided in the exploitation of these formations. Multiple stages and multiple clusters per stage along the horizontal wellbore are routinely used to create multiple transverse fractures which influence both initial production (IP) rate and decline, and create large contacted reservoir volumes (CRV). The use of these hydraulic fracturing and completion technologies, along with favorable market conditions of natural gas liquids, has made field development economic for Eagle Ford shale. Operators typically desire to identify a standardized completion design as soon as possible. Given the relatively new application of these hydraulic fracture techniques, treatment designs in the Eagle Ford shale often originate from designs in other North American shale plays. Given the rapid pace of development in the Eagle Ford shale, many operators continue to use these baseline designs and fail to develop and evaluate more rigorous engineering based treatments and evaluations.

The Eagle Ford shale play has had significant growth since 2009, with strong well performance in the condensate window. The gas, condensate and oil production from January – November 2011 was 221 Bcf, 18.7 MMbbl and 21.8 MMbbl respectively (Figure 1) [Tx RRC]. Horizontal drilling activity continues to grow throughout the field, with total rig count exceeding 200 rigs as of February 2012 (Figure 2).