The project goal is to extend insulated drill pipe (IDP) technology to high-temperature/high-pressure drilling applications in deep gas reservoirs by designing and testing IDP, while coordinating with industry to ensure the technology meets stakeholder needs.
Drill Cool Systems, Inc.
John Finger Consulting
Spears & Associates
Stress Engineering Inc.
T.H. Hill & Associates
Extremely high temperatures (>400 °F), exceptionally high pressures (>15,000 psi), exceedingly hard rock, and highly corrosive gases all combine to create a very hostile environment for well drilling and completion activities in search of deep gas resources. These conditions can lead to material and electronic failures, increased wear on equipment, and increased technical and safety risk due to an inability to monitor downhole conditions. High downhole temperatures historically have either driven the cost of reaching deep gas reservoirs to a level that makes their development uneconomic or have prevented access altogether through equipment failure.
One approach to dealing with these issues is simply to control the temperature of the downhole environment so that existing drilling technology can more easily survive. The application of insulation to drill pipe could provide a means to deliver a much cooler drilling fluid to the bottomhole assembly, allowing these components to successfully function in a more favorable environment.
The insulated drill pipe concept offers the potential to enhance drilling capabilities by allowing the use of logging-while-drilling and measurement-while-drilling tools under temperature conditions that are now prohibitive, and could reduce flat time by decreasing the failure rates of temperature-sensitive equipment. In wells where high temperature is the primary problem, the application of IDP technology could have a significant benefit through savings accrued primarily from problem avoidance, with the associated reduction in rig time and tool repair costs, as well as potential savings in repair costs for downhole equipment such as motors.
Results (Feb 2009)
The preliminary prototype IDP design was completed and underwent mechanical testing where it was demonstrated that adaptation of the parent drill pipe for IDP application did not degrade system mechanical performance. Testing was conducted by Stress Engineering Inc and included tensile, internal pressure, fatigue, torsion, elevated temperature and torsion tests. Activity was completed to design a procedure for testing potential inspection systems for the IDP design. The method was to include the machining of defects into raw drill pipe follwed by the installation of the IDP liner within the pipe and the testing various Non Destructive Evaluation techniques to discern and quantify damage through the IDP liner. Efforts were initiated to test the inspection procedure but finalization of industry feedback indicated serious concerns with the planned IDP design and as such activities in this area were halted. Solicitation of industry feedback on performance requirements and sizing of a final IDP prototype IDP design was completed by Spears and Associates Inc. and additional inquiry was performed via direct outreach from Drill Cool. Industry response was limited but in essence indicated a reluctance to accept the proposed IDP design due to concerns over effects on drill pipe hydraulics. Because of the inherent configuration of the proposed IDP design, there was inherent conflict between a given OD for maximum pipe strength in a given hole and having its ID as large as possible (for minimum pressure drop). This conflict was determined to be intractable with industry operators and as a result it was determined that there was not sufficient time or budget within the existing project to pursue an entirely new design. The project was altered to end at the conclusion of Phase 1 (eliminating Phase 2 manufacturing of a prototype and performance testing the system). Drill Cool may pursue alternative designs for the IDP but will do so outside of this project. The final report is available below under "Additional Information".