VAM drilling has come out with a new drill pipe called ‘Hydroclean’ that is designed to hydromechanically clean a well hole, reducing equivalent circulating density issues which lead to stuck pipe.
ERD (Extended Reach Drilling) Hole-Cleaning can significantly reduce occurrences of stuck pipe and nonproductive time. This is important to consider, as each year the global OCTG industry looses an estimated $2 Billion to rig inactivity.
Luc Van Puymbroeck Writes:
Relatively speaking, drill pipe is a small expenditure compared with the
nonproductive time (NPT) associated with its use. Studies have estimated global industry losses related to stuck pipe and loss circulation to be in the order of US $2 billion per year. This is more than twice the total amount spent to buy drill pipe in the first place and represents nearly 20% of the total NPT losses associated with drilling (Wellings & Co Survey, 2008, and Ivan et al, SPE 2004).
This also sets a framework around challenges and opportunities for drill pipe designs to increase efficiency and mitigate drilling risks. Complex and extended-reach drilling (ERD) well profiles are pushing drill pipe manufacturers to redefine performance limits, and those challenges are best met through a holistic engineered approach of the drill string design.
Hole cleaning & ECD
In many respects, the first approach to hole cleaning can look simple when considering only cuttings behavior by rotating the drill string and cuttings displacement using drilling fluid circulation. Mud rheology is also deemed to play a major role, but mud is only one part of a system approach, which requires all factors affecting cuttings behavior in the well to be addressed in concert. Analyzing cuttings ground by rotation of the drill string and cutting rates over the shakers is a first step toward developing hole-cleaning KPIs.
Efficient cuttings transport and keeping the well clean enough for trouble-free operations usually dictate the amount of time spent on cleaning the hole. Evaluation and performance analysis for drill string optimization, flat times, ECD, torque and drag are also commonly used for setting targets. The execution at the well site usually requires the drilling team to manage pre-established rig practices and procedures to achieve real-time performance improvement by monitoring the wellbore.
Pick-up weight is one performance indicator measured while tripping in and out of the hole and reciprocating the drill string. Implementing diligent hole-cleaning practices while tripping in with controlled axial speed and set flow rates, rotational speed at minimum levels, and ECD controls while moving the string upwards are other practical examples of hole-cleaning procedures in action. Measurement of pressure while drilling is routinely applied for monitoring cutting bed height equilibrium close to the bit and mostly used as an indicator of “out-of-control” hole cleaning.
The right approach to managing risks is to plan and address hole cleaning using a system approach. To this end, an in-depth performance analysis review of the drilling process, with emphasis on maximizing drilling time, is desired. When economically justifiable, the use of mechanical hole cleaning devices should be considered to drill highly deviated wells with large hole sizes.
New drill pipe design
A new drill pipe design integrating hydromechanical cleaning features in the tool joint has been developed to increase hole-cleaning efficiency while drilling and to address ECD issues commonly encountered in ERD and horizontal wells. The drill pipe features specially designed bladed scallops in each tool joint, producing hydromechanical effects without compromising drill string performance.
Efficient cuttings transport is critical to achieve optimum hole cleaning, especially in horizontal wells. As fluid velocities become insufficient to maintain a clean hole, cutting beds start to form where they cannot be avoided. The hydrodynamic effects of the Hydroclean drill pipe gradually reduce cutting bed height by mechanical erosion of stagnating cutting buildup. Cuttings deposited on the low side of the hole are scooped and kept in suspension in the annulus above the rotating drill pipe, where fluid velocities are highest. This will lead to safer and faster drilling requiring less time for cleanups.
The new drill pipe provides immediate degradation of cutting beds and enhances hole cleaning through a combination of hydromechanical effects, such as scooping of cuttings and mechanical erosion of cutting beds by each tool joint, as well as maintaining continuous flow of cuttings in the high velocity annular space of the hole and sustaining the conveyor belt effect for efficient cuttings transport. The tool joint also has a dual-OD profile for increased wellbore stand-off, reducing pipe friction forces and wear.
Similarly, for a 65° inclination and 400 gal/min flow rate, the Hydroclean drill string was shown to be as effective in hole cleaning as standard drill pipe with 20% higher flow rate.”
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