Deepwater Double-Take

A property’s value is—as they say in real estate—determined by its “location, location, location.” This adage rings particularly true in the Gulf of Mexico’s Mississippi Canyon Protraction Area (MCPA).

It is an area blessed with an abundance of natural resources and both storied successes and forgettable failures over decades of activity. The MCPA is home to many E&P bright spots—Blind Faith, Na Kika, Thunder Horse and Tubular Bells—that have kept deepwater activity robust, even in its darkest of days.

For Shell, the area has been especially bountiful, because many of the company’s deepwater development projects and prospects—Appomattox, Mars, Rydberg, Vicksburg, Vito and Ursa—are within the MCPA’s boundary lines. Three of the company’s six tension-leg platforms (TLPs)—brought online in 2014, 1999 and 1996, respectively—produce hydrocarbons from web-like expanses of subsea wells that stretch far out on the seafloor from beneath bright yellow legs.

With the installation of its latest TLP, Shell gave the MCPA the distinction of hosting the first such project to expand an operating deepwater GoM field. When first oil flowed through the Olympus TLP in February 2014, the expected lifespan of that field—Mars—was officially extended to at least 2050. Not too shabby for a field discovered in 1989 and put into production in 1996.

For its injection of new life into Mars, Investor has awarded Shell its Excellence Award for Best Field Rejuvenation of 2014.

Defying expectations

The Mars deepwater field lies roughly 130 miles southeast of New Orleans in about 3,000 feet of water. Shell is operator with a 71.5% interest in the field; BP holds the remaining 28.5%. When Shell discovered Mars, it was considered one of the GoM’s largest discoveries to date.

“We realized early on after discovering the field that it was truly a deepwater giant with a very prolific resource base within the reservoirs that we could be looking to develop for many decades to come,” said Derek Newberry, Shell’s business opportunity manager during the development and construction phases for the Mars B project.

Initial estimates determined that the field would have nearly 700 MMboe of resources. In the 18 years since production started, more than 770 MMboe have flowed through the Mars TLP that the company installed in 1996, according to Shell. It was the first TLP in the GoM to produce more than 100 Mboe/d, and it was designed to handle about 220 Mbbl/d and 220 MMcf/d during its economic life.

“The Mars Field really outperformed our expectations,” he said. “Our estimate of the resource base continued to grow as we developed the deepwater giant. We recognized there would be benefits to adding more infrastructure.”

The Mars B project will enable production in the field to reach more than 1 Bboe and to extend to 2050 and beyond.

Having significantly surpassed the original expectations, Shell announced in September 2010 that it had made the final investment decision to move forward with the Mars B Development Project. The project called for the installation of the Olympus TLP, development of the West Boreas and South Deimos subsea fields and the installation of pipelines to a new shallow-water platform.

“There are many things that are unique about Mars B,” Newberry added. “It is worth highlighting that this is really the first time in the deepwater Gulf of Mexico where we’ve executed such a significant development and where we’re putting in significant additional infrastructure to enhance infrastructure that was already there, the Mars tension-leg platform. This really is a first for a project of this magnitude in the deepwater Gulf of Mexico.”

Mars B will enable production in the field to reach more than 1 Bboe, the company reported. And what does it mean for the field’s life expectancy?

“With the Mars tension-leg platform, we were looking at an end of facility life in 2035. We have designed the Olympus tension-leg platform to be producing well into 2050 and beyond,” Newberry said.

Seeing clearly

The decision to move forward with Mars B was supported in part by seismic technology advancements that helped reveal the truly prolific nature of the deepwater giant.

“When we looked at the geology in the area that surrounds the Mars Field, it showed great potential for further exploration discoveries,” Newberry said. “One of the keys to unlocking these exploration prospects that ultimately became discoveries was the advancement of seismic technologies.”

A key piece was the 3-D seismic the company had acquired with streamers in the 1990s and into the early 2000s, he said. It was the advent of wide-azimuth (WAZ) seismic acquisition that really helped clear up the Mars picture.

“Where the Mars Field is located there are large salt bodies, and it’s very difficult to use seismic to see through the salt and understand what’s underneath,” he said. “With older versions of seismic technologies, if you can imagine a table with some frosted glass and if you put a book underneath and look at it with conventional seismic down through that frosted glass, you get a rough idea for what the book may be, but you don’t see it very clearly.

“What WAZ allowed us to do was move away from that table and see not through the frosted glass, but underneath the frosted glass without having to look through it. It really allowed us to look underneath the salt and get a more precise image of the subsurface and the potential exploration prospects that were there.”

Mars B is made up of production opportunities from the Mars Field and from two subsea fields—West Boreas and South Deimos—that are tied back by subsea infrastructure. The target reservoirs for Mars B are located at an approximate depth of two miles to four miles below sea level.

As an example of the persistence of technology, Newberry said that the company drilled the Boreas exploratory well based on conventional 3-D seismic data acquired in 2004, but it turned out to be a dry hole.

“We did not find what we were looking for. The sand was not there; the hydrocarbons were not there. The persistence of technology and the development of new acquisition techniques allowed us to put seismic geophone nodes on the seabed. We went out with this new seismic technology in 2008 and discovered that the original well we had drilled missed the hydrocarbon pay zone by a few hundred feet.

“With these new data we were able to sharpen up the subsurface image and really enhance our understanding of the subsurface. We went back to the prospect and drilled the well in early 2009 that would become the West Boreas discovery. We drilled that pay in April of 2009. First production from the Olympus TLP came from that West Boreas Field, from which we’re currently producing about 40 Mboe per day.”

Making Mars B

The Olympus and the Mars TLPs—located about one mile apart—make for a staggering double landmark on the GoM horizon, with the Ursa TLP visible from its location several kilometers away to the east of the duo.

“I see the Mars B project as providing three significant pieces of infrastructure that we put out into the Gulf of Mexico,” Newberry said. “The cornerstone is Olympus.”

Crushing the scales at 126,000 tons, Olympus TLP is more than double the weight of Mars TLP. It stands more than 40 stories tall from the base of its hull to the top of its derrick and has a production capacity of 100 Mboe/d. As the largest jewel in Shell’s deepwater GoM crown, the Olympus TLP was delivered to its final home in MC 807 more than six months ahead of schedule.

In just under a year from its arrival in Ingleside, Texas, the Olympus TLP began first production from two subsea wells completed by the Noble Bully.

Designed for a service life of 45 years, among its many technology advancements made to adhere to more stringent specifications the Olympus TLP features a direct vertical access rig that stands just under 200 feet tall. The rig has the ability to skid over all 24 well slots and can be made secure for a 1,000-year storm. It has a maximum static hook load of up to 2 MMlb, almost double the hook load of the Mars TLP, according to a Shell Offshore Technology Conference paper.

Dockwise transported the Olympus hull from Busan, Korea, to Ingleside, Texas, onboard the Blue Marlin.

Subsea and export system

The second piece of the infrastructure puzzle was the subsea development of West Boreas and South Deimos fields.

“The fields are located approximately three miles to the west, northwest of the Olympus TLP, with a single-production manifold on the seabed,” Newberry said. “Ultimately, we will have six subsea wells drilled from that manifold. It is tied back via a subsea system.”

Outfitted with six 15,000-psi rated enhanced vertical deepwater trees, West Boreas Field was the first to use this type of tree system, according to FMC Technologies.

“The third piece is our export solution. We have dedicated oil and gas export in pipelines that depart from Olympus TLP to the West Delta 143 Complex,” he said. “There were two shallow-water platforms there originally, and as part of Mars B we added a third shallow-water platform, which was West Delta 143C. That’s the infrastructure: our cornerstone with the Olympus TLP, our subsea system for production and our export solution with dedicated pipelines and shallow-water platform.”

Operating differently

The Mars B Development is one of the most technologically advanced fields in the GoM. When first oil flowed in February, the switch flip to commence production occurred onshore, not off.

“I was on Olympus when we opened the subsea well. It was a very special moment, to see a venture of this size with many millions of man-hours to get to that point,” Newberry said. “It was a unique startup in that we have a fiber-optic cable that connects an onshore operations control room to the control room on the Olympus. We actually opened up production offshore via technology at One Shell Square in New Orleans.”

Located at One Shell Square is the Olympus Integrated Operations Center (IOC). It is connected via fiber-optic link to the Olympus Remote Control Room (RCR), providing a way for shore-based operators to monitor in real-time the data and activities underway on the Olympus TLP.

The IOC is a place where the offshore operations team can work more closely with the onshore engineering and technical support teams and, according to the company, helps create a more efficient operation. In one example the company provided, a group of 11 engineers who would traditionally perform the platform installation work offshore were able to perform 75% of the work from the RCR. The IOC concept works so well that the company plans to design all offshore production platforms using this concept.

While the Olympus TLP is the latest and largest jewel in Shell’s deepwater crown, it is certainly not the last, as Shell continues to further establish its leadership position in the Gulf.