By Mike Killalea, editor & publisher
When it comes to cutting-edge technology, dual-gradient drilling (DGD) and well-construction automation are the sharpest knives in the drawer.
NO SINGLE DGD
The first thing to understand about dual-gradient drilling is that there is no such thing. That is, no single DGD technology exists. Today’s DG technology is analogous to the burgeoning “green” car revolution. The array of proposed automotive alternatives is dazzling – electric cars, hybrid gasoline/battery, fuel cells. There is no single “green” car.
So it is with DGD. Several variations on the theme exist – dual gradient with mud lift, controlled annular mud level, mud line pumping (riserless), dual-gradient gas injection in the annulus, and dual-gradient fluid or hollow glass spheres (HGS) in the annulus.
Many believe that DGD offers game-changing improvements in efficiency and safety for deepwater, subsea drilling. This is because DGD promises to enable an effective solution to the narrow window between pore and fracture pressure profiles common in many deepwater wells, especially in the Gulf of Mexico.
The concept dates to the 1960s, but it was not until the late 1990s that the industry focused on implementing DGD. But high costs and another bout of oil-price collapse relegated DGD to the back burner. Now, with renewed interest in deepwater, the idea is again catching fire.
Statoil has determined that DGD is feasible for a number of Norwegian fields. As reported by DC, Chevron, in conjunction with AGR Drilling Services, GE Oil and Gas and Pacific Drilling, is set to deploy the first purpose-built DGD rig, the drillship Pacific Santa Ana, in the Gulf of Mexico in 2011. The Chevron DGD team already has a prospect identified to drill – and this is not a test well.
IADC DGD WORKSHOP
Given the excitement and need for a better industrywide understanding of dual-gradient systems, IADC is organizing a DGD workshop on 5 May 2011 in Houston. The event will cover potential benefits of DGD, explain and differentiate types of DGD, implications for well control, testing the concept, and DGD implications for well design, cementing and completions.
IADC, through its Underbalanced Operations and Managed Pressure Drilling Committee, will also explore forming a DGD Subcommittee to work toward best practices. The proposal is on the agenda for the committee’s 7-8 December meeting in Reading, England, which is sponsored by BG Group.
Automation is another potential game changer. High degrees of automation are commonplace in many manufacturing operations but have yet to succeed on a grand scale for well construction. Reasons include lack of a common communication protocol and language allowing multiple third-party companies to connect to and control drilling equipment on a rig, as well as pesky reliability issues.
The goal is so important that both IADC and SPE are working toward solutions, through the IADC Advanced Rig Technology (ART) Committee and SPE Drilling Systems Automation Technical Section (DSATS), respectively.
In Amsterdam on 28 February, the day before the 2011 SPE/IADC Drilling Conference, the two groups will convene an afternoon of presentations and discussion on advancing well-construction automation. As envisioned, the event will feature updates on ART and DSATS and a panel discussion on delivering increased and sustainable value through automated well-construction systems.
The IADC Dual Gradient Workshop and the DSATS/ART Forum are just the latest examples of IADC fulfilling its mission of advancing well-construction technology. I hope to see you at one or even both of these events.
Mike Killalea can be reached via email at firstname.lastname@example.org.