Hybrid coiled-tubing system offers stimulation option for extended-reach wells

Posted on 12 April 2011

A new hybrid coiled-tubing (CT) system is enabling the efficient use of CT in extended-reach wells. Fraser McNeil of Halliburton discussed the system and its application during the 2011 SPE/ICOTA Coiled Tubing and Well Intervention Conference and Exhibition last week in The Woodlands.

Deeper well completions with extended-reach horizontal laterals have presented unique problems when needing to perform live well intervention operations, Mr McNeil said. While larger CT sizes are preferred in order to achieve higher treatment rates and cleanup rates and in getting to the target depth when running in hole, “the ever-increasing depths of the wells present difficulties for large CT.”

A hybrid system that uses both CT and jointed pipe has been developed and applied in the Bakken Shale west of Westby, Mont. The goal of the system, according to Mr McNeil, is to combine the advantages of CT and jointed pipe in extended-reach wells and eliminate the disadvantages.

The primary disadvantage of a CT drilling system is its inability to reach target depth on long, extended-reach wells while applying sufficient weight and torque at the bit to drill. Current methods that enable to CT to drill at these depths are more expensive than conventional systems and may not deliver the desired results, according to Mr McNeil.

Also, when limited to the use of small outside-diameter (OD) CT, the fluid flow rate pumped may be limited by pressure and velocity, which limits the stimulation processes, especially in deep-reach wells, he said.

Jointed pipe offers some advantages for live well intervention operations in deep-reach wells as it provides large-OD pipe with higher pump rates and lower pump pressures, has a higher pull capacity, carries less risk of cutting and damaging pipe, and can achieve deeper horizontal penetration before lock-up.

“The hybrid system is designed to use both CT and jointed pipe in a single workstring,” Mr McNeil said. “This enhances the capabilities of jointed pipe by reducing the overall job time and improving safety and efficiency for deeper wells, multi-zone fracture treatments, cleanout service applications and completion tubing installation.”

The solution was applied in the Bakken, where optimum production is achieved by creating numerous multiple transverse fractures and each fracture must be contained within the lower, middle and upper formations. The hybrid system enabled low-rate, hydrajet-assisted fracturing to limit unwanted fracture growth, Mr McNeil said.

The CT and jointed pipe that made up the system were run successfully without chemical or mechanical aid to target depth, and the time to reach target depth was greatly reduced compared with the use of standard stick pipe. The time to move between zones was also decreased. Eighteen zones were completed in four days.

For more information, please see SPE 142769 “New Hybrid System Brings the Flexibility of Coiled Tubing to Long, Extended-Reach Wells,” by F. McNeil, S.D. Lindsay, R. Lyons and R.P. Gracey.

Leave a Reply

*

FEATURED MICROSITES


Recent Drilling News

  • 15 April 2015

    DNV unveils Recommended Practice to standardize steel forgings for subsea applications

    Steel forgings are important building blocks for subsea components and are often tailored to meet end-users’ specific requirements. This results in long delivery times...

  • 14 April 2015

    BSEE issues proposed BOP, well control regulations for public comment

    On 13 April, US Secretary of the Interior Sally Jewell announced proposed regulations that call for more...

  • 14 April 2015

    Wood Mackenzie: Deeper cuts may be needed to achieve cash flow neutrality

    The rapid and aggressive response by oil and gas companies to low oil prices has stabilized the sector...

  • 13 April 2015

    UKOG completes Weald Basin PEDL126 acquisition from Magellan

    UK Oil and Gas now holds 100% interest in the Weald Basin onshore license PEDL126 after acquiring...

  • 13 April 2015

    Noble Energy to drill Humpback, Rhea offshore Falkland Islands this year

    Noble Energy has acquired a 75% interest and operatorship of the PL001 license in the North Falkland Basin from...

  • Read more news