A New Barnett Shale Horizontal Completion Lowers Cost and Improves Efficiency

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 103046, "New Barnett Shale Horizontal Completion Lowers Cost and Improves Efficiency," by D. Lohoefer, SPE, Eagle Oil and Gas, and J. Athans, SPE, and R. Seale, SPE, Packers Plus Energy Services, prepared for the 2006 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 24–27 September. A new completion has been deployed in the Barnett shale that is fast, efficient, and less costly than the former standard completion. By use of specially designed mechanical openhole packers run on the production liner, mechanical diversion in the openhole section can be accomplished at predetermined points. Each stage in the horizontal section can have a specifically designed fracturing or stimulation procedure. The system also allows all of the fracturing or stimulation treatments to be pumped in one continuous operation, with the added benefit of restimulating all or selected intervals at a later date if desired. Introduction During the past 5 years, horizontal drilling has become the exploitation method of choice in the Barnett shale. Several completion methods have evolved during this time. In one standard completion process, the horizontal section is cased and cemented, and completing the well consists of running and setting a composite plug on coiled tubing (CT), perforating, stimulating, flowing the well back, and repeating the process for the required number of stimulations for the horizontal wellbore (Fig. 1). This process is very costly and time consuming, with the added risk of having to remove the composite plugs; also, there currently is no viable method for restimulating these wells at a later date. One of the most successful and efficient completion methods has been a recently developed openhole completion providing mechanical diversion. Nearly 6 years ago, a technology gap was identified for openhole completions in horizontal wells. It was determined that mechanical diversion was needed to fracture various sections of the lateral effectively. Without mechanical diversion, there was no viable way to direct the fracture for optimal production results. Fracturing operations were concentrated in one particular section of the horizontal well, typically at the heel, thus leaving much of the wellbore unstimulated and, ultimately, unproductive. It is from these initial system developments that the horizontal openhole fracturing system that exists today was produced. A mechanical openhole packer was developed specifically to withstand the harsh environments encountered in the high-pressure/high-temperature (HP/HT) fracturing environment. The packer and system components were designed to hold 10,000-psi differential operating pressure at temperatures up to 425°F while having expansion capabilities greater than 50% of the original packer outside diameter. System developments also included fluid-deployment systems placed between the openhole packers to deliver the fracture treatment in the optimal position. This field-proven system is now more than 4 years old, with more than 300 successful systems deployed in horizontal openhole wells. Applications include wells from 1,000 to 15,000 ft true vertical depth with horizontal wellbores as long as 6,700 ft. Further evidence of the versatility of the system is the ability to design the stage length at the rigsite and place the components from the two systems together to optimize the stimulation for a particular zone or to segregate a nonproductive zone.