Field Demonstraton of Existing Microhole Coiled Tubing Rig (MCTR) Technology

The performance of an advanced Microhole Coiled Tubing Rig (MCTR) has been measured in the field during the drilling of 25 test wells in the Niobrara formation of Western Kansas and Eastern Colorado. The coiled tubing (CT) rig designed, built and operated by Advanced Drilling Technologies (ADT), was documented in its performance by GTI staff in the course of drilling wells ranging in depth from 500 to nearly 3,000 feet. Access to well sites in the Niobrara for documenting CT rig performance was provided by Rosewood Resources of Arlington, VA. The ADT CT rig was selected for field performance evaluation because it is one of the most advanced commercial CT rig designs that demonstrate a high degree of process integration and ease of set-up and operation. Employing an information collection protocol, data was collected from the ADT CT rig during 25 drilling events that encompassed a wide range of depths and drilling conditions in the Niobrara. Information collected included time-function data, selected parametric information indicating CT rig operational conditions, staffing levels, and field observations of the CT rig in each phase of operation, from rig up to rig down. The data obtained in this field evaluation indicates that the ADT CT rig exhibited excellent performance in the drilling and completion of more than 25 wells in the Niobrara under varied drilling depths and formation conditions. In the majority of the 25 project well drilling events, ROP values ranged between 300 and 620 feet per hour. For all but the lowest 2 wells, ROP values averaged approximately 400 feet per hour, representing an excellent drilling capability. Most wells of depths between 500 and 2,000 feet were drilled at a total functional rig time of less than 16 hours; for wells as deep at 2,500 to 3,000 feet, the total rig time for the CT unit is usually well under one day. About 40-55 percent of the functional rig time is divided evenly between drilling and casing/cementing. The balance of time is divided among the remaining four functions of rig up/rig down, logging, lay down bottomhole assembly, and pick up bottomhole assembly. Observations made during all phases of CT rig operation at each of the project well installations have verified a number of characteristics of the technology that represent advantages that can produce significant savings of 25-35 percent per well. Attributes of the CT rig performance include: (1) Excellent hole quality with hole deviation amounting to 1-2 degrees; (2) Reduced need for auxiliary equipment; (3) Efficient rig mobilization requiring only four trailers; (4) Capability of ''Zero Discharge''operation; (5) Improved safety; and, (6) Measurement while drilling capability. In addition, commercial cost data indicates that the CT rig reduces drilling costs by 25 to 35% compared to conventional drilling technology. Widespread commercial use of the Microhole Coiled Tubing technology in the United States for onshore Lower-48 drilling has the potential of achieving substantially positive impacts in terms of savings to the industry and resource expansion. Successfully commercialized Microhole CT Rig Technology is projected to achieve cumulative savings in Lower-48 onshore drilling expenditures of approximately 6.8 billion dollars by 2025. The reduced cost of CT microhole drilling is projected to enable the development of gas resources that would not have been economic with conventional methods. Because of the reduced cost of drilling achieved with CT rig technology, it is estimated that an additional 22 Tcf of gas resource will become economic to develop. In the future, the Microhole Coiled Tubing Rig represents an important platform for the continued improvement of drilling that draws on a new generation of various technologies to achieve goals of improved drilling cost and reduced impact to the environment.

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