Geo-musings: A Close Look Below the Curtains

Personal Connection

The Stena DrillMAX is currently located at Boca Sint Michiel bay on Curaçao, one of my favorite beaches since childhood. This iconic fisherman’s beach, where fresh fried fish is served, is now also used for stacking drill ships, along with other locations like Caracas bay. This beach formerly housed facilities for the Dutch Royal Marines stationed in Parera, Willemstad. As a child, I once had the memorable experience of meeting and speaking with Prince Bernhard, the former husband of Queen Juliana, while he was swimming there.

Why TotalEnergies Chose the Stena DrillMAX with MPD for Block 58

TotalEnergies has contracted the Stena DrillMAX equipped with Managed Pressure Drilling (MPD) capability to drill in Block 58, Suriname, scheduled for Q2 2025. What does this technical choice tell us about the subsurface challenges they anticipate?

Geological Complexity & Overpressure Challenges

Block 58 represents the southeastern extension of the prolific Stabroek Block, forming part of the Golden Lane trend. However, several factors make it more complex:

• Different sediment supply systems compared to Guyana
• Distinct structural configuration
• More challenging pressure regimes

According to industry reports, in a nearby western area, the Jaguar well had to be abandoned in 2012 due to “unexpected” ultra-high pressures reaching approximately 16,000 psi—beyond the drill ship’s handling capacity. This decision potentially left over 500 million barrels of resources undeveloped (Offshore Magazine, 2013).

The block contains Upper Cretaceous deepwater turbidites (Campanian-Maastrichtian) and Santonian reservoirs that appear more compartmentalized and heterogeneous than those in Stabroek. Rapid sedimentation during the late Neogene has caused undercompaction and overpressure conditions, making MPD technology essential for controlling wellbore pressure during drilling operations.

Thermal Maturity & Fluid Differences

How do the reservoirs in Block 58 compare to the highly successful Stabroek block?

In Stabroek, oil accumulations occur in high-quality reservoirs at moderate burial depths, resulting in light crude (32–40° API) with relatively low gas content. In contrast, Block 58 and 52 feature:

• Deeper, hotter source rock conditions
• Higher thermal maturity profiles
• A mixture of light oil and gas-condensate
• Significantly higher gas/oil ratios (GOR)

These differences substantially impact exploration strategies and production methods, necessitating sophisticated pressure management and gas handling facilities.

The Strategic Selection of Stena DrillMAX with MPD

The Stena DrillMAX is an ultra-deepwater drilling vessel specifically equipped for complex, high-pressure drilling environments. Its MPD system provides several critical advantages:

• Real-time pressure control throughout drilling operations
• Prevention of well control incidents in high-pressure zones
• Optimization of drilling performance in challenging formations
• Enhanced safety protocols for high-pressure/high-temperature conditions

Given Block 58’s significant resource potential but challenging pressure and fluid conditions, MPD technology represents the key to unlocking these resources safely and efficiently. As noted in the Journal of Petroleum Technology (2022), MPD has become increasingly essential for developing complex deepwater reservoirs where conventional drilling methods face limitations.

Have you considered how these technological adaptations might influence development costs and timelines for Block 58 compared to neighboring fields?