SPE/IADC '19: Day three presentations feature MPD, automation and offshore innovation

THE HAGUE -- Some of the best was held for the last in the Technical Program at the annual SPE-IADC Drilling Conference, held in The Hague, the Netherlands. 

Among the session titles on Thursday, the third and final day, March 7, were Managed Pressure Drilling; Directional Drilling; Offshore Drilling; Drilling Dynamics and Mechanics; Drilling Automation; and Well Cementing and Zonal Isolation. What follows is a sampling of presentations that are broadly representative of the day’s offerings.

In the morning, in the MPD session, authors from Schlumberger and Petro-Hunt presented the paper, “Revitalising the Bakken with Managed Pressure Driling.” For several years, the operator, Petro-Hunt, has been drilling actively in the Williston basin, including the Bakken shale. As development has progressed, lateral sections have increased steadily, and are now in the 10,000-ft range. Additionally, the average days to complete these sections also have increased to 14. 

Drilled conventionally since the beginning of the campaign, these wells have been plagued with problems, such as stuck pipe, mud loses and pressure issues, among others. As a possible solution, MPD was tried on a test well. Accordingly, an MPD design for an optimized mud weight and surface backpressure schedule was utilized in the entire production section, including tripping and liner run operations. For the test well, a 9,622-ft lateral was drilled for seven days, including casing run and cementing. Performance-driven application of MPD effectively reduced the operating days in half.

The successful application of MPD achieved the main objective, to reduce the operating days to drill the production section. This was achieved through ROP improvements, due to a lower mud weight and application of back pressure to minimize surface gas, as well as having the MPD package to handle the gas at the surface while drilling. During three months, starting from the first test well, the campaign continued with using MPD technology, and one more rig was added. So far, five wells have been completed with MPD improvements, yielding reduced operating time.   

Also in the morning, during the Offshore Drilling session, authors from Total and O&G Subsea Subsea Products Systems presented the paper, “Subsea Xmas Tree and Completion Operations on Two Different Subsea Providers with a Single Rig Using One Common IWOCS System.” As one author described the problem, a subsea field development offshore Congo, West Africa, had been installed with subsea production equipment designed and manufactured by two different subsea equipment suppliers.

Accordingly, it had been a major challenge to perform subsea intervention and installation with just one drilling rig available for this subsea development, as the equipment from different subsea suppliers was not design-compatible. The conventional approach would be to change out the topside installation and intervention equipment from one manufacturer to that of the other on the rig. 

But given that this solution was far too expensive and time-consuming, a need for one universal subsea installation and intervention system became a requirement. Thus, the operator, Total, along with two subsea production equipment suppliers, was able to design, manufacture and implement one universal drilling system, referred to as IDIMS (Interface for Dual Intervention Mode System). IDIMS say the authors, increases the operational response while lowering the intervention cost. IIDIMS allows one single rig to intervene, drill and complete with two different subsea production equipment suppliers at a lower cost and with a shorter lead-time, which, the authors say, is a first in the industry.

For operators, IDIMS XT and TH modes represent a major innovation to reduce costs and drilling times for mature offshore fields equipped with different subsea production systems and

equipment. Over three years, this innovation saved $107 million at the field. The IDIMS concept can be reproduced and developed to intervene and drill other subsea field developments, with even more than two subsea suppliers. A single rig would then be able to operate on all of the subsea wellheads, tubing hangers, subsea XT installed/to be installed in one area, significantly reducing project development costs.

During the afternoon Thursday, in the Drilling Automation II session, authors from the NORCE research organization (Norway) and Equinor presented the paper, “Automatic Control of Mud Pumps, Draw-works and Top-drive on a Floater.” The presentation covered the application of safeguards, safety triggers and automated procedures to control the mud-pumps, hoisting system and top-drive, which allows for safer, more consistent and more efficient drilling.

Attempting to apply drilling automation on a floater, the presenter noted, requires managing the impact of the unpredictable movement of the drillstring, induced by heave movements.

Because of drillstring elasticity and continuous movement of the rig, it is challenging, he said, to estimate the bit position, the bottomhole depth or the instantaneous ROP. Yet, these estimations are crucial for evaluating cuttings production and their transport, or dynamic open-hole pressures. 

Furthermore, he noted that the variability of the top- of-string movement can change abruptly when heave compensation is turned on or off, or depending on the efficiency of the heave compensation system. These items impact the forward-looking strategy to determine safe drilling parameters. An existing drilling automation system, originally designed for fixed platforms, has now been modified to meet these new requirements.

For this first adaptation, only vertical drilling has been considered. Heave movements with, and without, compensation are constantly monitored, so that sudden or slow changes in amplitudes get accounted for. Induced effects on downhole pressures are estimated via hydraulic simulations for a wide range of drilling and heave scenarios. 

Consequently, the automation system design had to be modified considerably to incorporate this additional dimension. The resulting system has drilled three exploration wells, in 11 sections. Offshore drilling operations are characterized by a large variability of conditions. On a floater, said the presenter, the drilling context is even more challenging, as it is subject to ever- changing weather conditions. Yet, by utilizing model-based drilling automation solutions, it is possible to improve drilling efficiency.