IMPROVING DRILLING PERFORMANCE USING ADVANCED DRILLPIPE WITH STREAMLINE CONNECTIONS

The trend to drill deeper and longer extended reach wells with long, slim hole 6 1/8 in. horizontal production intervals has revealed serious limitations in the standard 3 1/2 in. drillpipe conventionally used in these applications. ConocoPhillips realized significant drilling performance and economic benefits by utilizing 4 in. drillpipe with advanced design, slim hole connections in place of standard 3 1/2 in. drillpipe. The streamline drillpipe design configuration resulted in successful drilling of longer slim hole intervals with enhanced torsional and tensile strength, increased stiffness and improved hydraulic performance at a lower overall cost. ConocoPhillips' Alpine field on the western North Slope of Alaska required Extended Reach Drilling to deliver pay zone objectives located at measured depths between 8800 ft and 21178 ft with lateral lengths up to 7830 ft MD. Complex 3 dimensional paths are employed in the field often resulting in tortuosity considerations and associated elevated torsional and compressive load requirements for the drillstring.

The slim hole 4 in. drillstring design permitted use of the same drill bit/casing program as employed previously with conventional 3 1/2 in. pipe. A high performance, double shoulder connection for 4 in. drillpipe was selected that maintained a tool joint outside diameter similar to conventional 3 1/2 in. drillpipe tool joints. This streamline connection maintains fishing ability in both cased and open hole. The 4 in. high performance drillpipe was suitable for drilling larger diameter intermediate hole sections eliminating a requirement for 5 in. drillpipe. This drastically reduced the amount of time spend picking up and laying down drillstrings, resulting in reduced HSE exposure handling drillpipe.

This paper addresses these considerations and provides case histories that clearly illustrate the benefits and savings that can be achieved and the limitations using this new drillpipe design configuration.