ExxonMobil’s largest subsea development

The Kizomba C Mondo project offshore Angola is the first of 12 planned major startups for 2008.

This article originally appeared in the Lamp, 2008 — Number 1

A quiet celebration of first oil on New Year’s Day began the latest round of production from Block 15, Angola’s most prolific offshore concession. The project, which taps the Mondo, Saxi and Batuque fields, is expected to recover some 200,000 barrels of oil a day and raise the daily production from Block 15 to more than 700,000 barrels.

The multibillion-dollar deepwater development includes two Floating Production, Storage and Offloading (FPSO) vessels and 36 subsea wells, making it ExxonMobil’s largest subsea venture. The twin ships are the fourth and fifth production hubs on Block 15, following Xikomba (2003), Kizomba A (2004) and Kizomba B (2005). One FPSO is operating now, and the second should arrive in Angola in April and commence production in June. The drilling program on Kizomba C will continue through 2009.

With a 40 percent share, Esso Angola has the largest interest of the joint venturers and is operator of the project for the concessionaire, Sonangol. Other participants in Block 15 are BP Exploration (Angola) Limited (26.67 percent), ENI Angola Exploration B.V. (20 percent) and Statoil Angola 15 AS (13.33 percent).

“The on-time, on-budget startup of the Kizomba C project is another example of our commitment to developing global energy resources in an environmentally and socially responsible manner,” says Neil Duffin, president of ExxonMobil Development Company (EMDC).

“Our goal is to secure safe and reliable sources of energy to meet growing world demand, and the startup of Kizomba C is another important step in our work with Sonangol to develop Angola’s significant petroleum resources,” Duffin says. “In addition, a number of other significant projects are expected to begin operations this year, including LNG receiving terminals in the United Kingdom and Italy, the world’s largest LNG production facilities in Qatar, and a new, larger and more efficient class of LNG delivery vessels, as well as the startup of the expanded East Area natural gas liquids project offshore Nigeria.”

More capacity at home

Along with the boost in oil and gas production, Kizomba C has further reinforced Angola’s increasing ability to support its energy industry through local infrastructure improvements, increased national content and training of nationals. A fundamental ExxonMobil goal is to help develop human, social and economic capacity which, in turn, benefits a country’s people, communities and businesses over the long term. For example, a decade ago in Angola, nearly everything needed in the field was brought in from other countries. Today, in large part through ExxonMobil’s ever-growing commitments, more construction, manufacturing, fabrication and state-of-the-art technologies are becoming available there. High-tech welding is a case in point.

“It takes exceptional skill to assemble the sophisticated subsea trees, manifolds and the rest of the kit for Kizomba C,” says Mike Flynn, EMDC’s vice president for deepwater projects.

“We are pleased that Angolan companies and workers can meet this important supply need,” Flynn adds. “Their work is impressive, which is one reason we were comfortable building the FPSOs’ high-strength steel turrets and all 14 of the subsea manifolds in Angola.”

Umbilical lines – the veins and arteries of any subsea development — are also being manufactured in the country. The umbilicals contain all of the hydraulic fluid and electrical connections needed to communicate, control and monitor the performance of all subsea systems for up to three miles (five kilometers) from the FPSO in approximately 2,400 feet (732 meters) of water.

“On each job for the last 10 years, we have worked with Sonangol to embed new technology and increase Angola’s manufacturing capacity,” Flynn says. “There are now a host of high-quality fabrication yards in Angola. We’re also seeing a strong growth in technical capacity so that much of the engineering work for future projects is planned to be done there as well.”

The challenges

With three production facilities already operating in Block 15, coupled with their almost daily tanker traffic, building Kizomba C took extraordinary planning.

“First, we worked with the geoscientists and reservoir engineers to decide where the wells should be,” says Ken Larson, Kizomba C senior project manager. “Kizomba C is actually three fields, each with multiple reservoirs. So it was imperative that we had the proper placement and number of wells to get the maximum coverage.”

To save time and money, several wells are drilled from one location or drill center, with curved and horizontal wellbores stretching as far as 20,000 feet (6,000 meters) to tap distant reservoirs.

“Each of the three fields has several such drill centers, and each drill center feeds wellbore production through subsea wells, manifolds and flowlines to the two FPSO vessels on the surface. The FPSOs then separate oil, water and gas. Oil is transferred to ocean-going tankers, and water and gas are reinjected into the reservoirs for pressure maintenance. Eventually, the reinjected gas will be recovered and converted to liquefied natural gas (LNG), a product that Angola can sell to markets in North America, Europe and Asia,” says Larson.

Perhaps the most significant accomplishment was the project’s world-class safety performance.This was achieved by working closely with the multiple contractors and promoting safety leadership within their respective organizations. As a result, the Kizomba C development achieved outstanding results: Work was completed in multiple fabrication yards in Angola without a lost-time accident; at the Singapore shipyard that built the FPSO, safety performance was six times better than industry average; and the 2007 offshore construction campaign was completed without a single recordable or lost-time accident.

Some assembly required

“ExxonMobil’s experience in managing large projects is one thing that sets it apart from other companies,” Larson says. “Kizomba C was essentially two multibillion-dollar projects, running in parallel with a single EMDC project team, under an unprecedented two-year execution schedule, coupled with a complex and highly choreographed installation campaign.”

Throughout the offshore installation, the team had to make constant adjustments to the schedule. If any equipment arrived late, it would hold up the work. If any arrived early, it would be in the way. Drilling vessels, for example, had to be carefully scheduled to efficiently utilize the expensive vessels and prevent downtime.

“With this complex installation, we naturally had issues to deal with,” says Joe Albiez, project manager for subsea systems. “The first installation vessels arrived in August 2007. For the next four months, we had as many as seven major vessels, plus the tugs and supply boats to support them, all working in a relatively small area, interacting every day with the drilling rigs and the Mondo field FPSO.”

To finish on time and on budget, the project team and its contractors had to be in tune.

“We developed a high level of trust and communication among all the contractor, production, drilling and project team members,” Albiez says. “Challenges came up constantly that, if not addressed immediately, meant huge additional expenditures for installation and drilling equipment. If anyone had a problem or needed something, it cascaded to all parties involved and we had to respond quickly and decisively as a single team. That was the mentality of the project: that everybody counted on each other and performed with the team’s best interest in mind.”