Liza Prospect Development, Stabroek Block, Guyana
The Liza prospect is located approximately 120 miles (193km) offshore Guyana in the Stabroek block, which is operated by ExxonMobil affiliate, Esso Exploration and Production Guyana.
Esso Exploration owns a 45% interest in the block, while Hess Guyana Exploration owns 30% and CNOOC Nexen Petroleum Guyana owns the remaining 25% interest.
The Liza prospect is planned to be developed in phases. Esso Exploration has submitted a plan for phase one development of the field to Environmental Protection Agency Guyana in August 2016.
First oil production from the field is expected in 2020.
Liza prospect location
The Liza prospect lies in the Stabroek block, which is spread over 26,800km² (6.6 million acres) offshore Guyana. The Guyana Basin is a relatively unexplored area with very few drilling activities being carried out.
Earlier exploration activities in the basin were carried out by other companies outside the southern boundaries of the Stabroek block in the 1970s. A total of 22 wells were drilled in the area, all of which proved non-commercial.
Despite the earlier unsuccessful drilling activities, initial seismic data and geologic analysis indicated the presence of oil and gas plays in the block. Based on this data, Esso Exploration commenced drilling activities in the Stabroek block. It became the first company to drill in the block since the 1970s.
Geology and reserves
The Stabroek block contains sediments of the Amazonian origin, which have been deposited by the Guiana Current. Seismic data collected in the region has indicated the presence of multiple play types such as Cretaceous and amplitude-supported plays containing stratigraphic on-laps, turbidites and basin floor fans.
The Liza prospect is estimated to contain recoverable reserves of 800 million to 1.4 billion metric barrels of oil equivalent.
Liza prospect appraisal and well details
Oil in the Stabroek block was discovered with the drilling of the Liza-1 well in May 2015, which encountered more than 295ft (90m) of oil-bearing sandstone reservoirs. The well was drilled by the Deepwater Champion 120 drillship.
Esso Exploration drilled a second well, named Liza-2, in June 2016 approximately two miles (3.3km) away from Liza-1 well to appraise the field. The well was drilled to a depth of 17,963ft (5,475m) by the Stena Carron drillship and encountered 190ft of oil-bearing sandstone reservoirs.
Following the drilling of Liza-2, ExxonMobil performed an extensive 3-D seismic survey covering an area of 6,500 square miles. Two seismic vessels were used to collect the data.
Based on the seismic survey, a third appraisal well named Liza-3 was successfully completed in September 2016 to further appraise the field. The well confirmed the commercial viability of the Liza prospect.
Phase one field development of the Liza prospect
Esso Exploration is currently developing the pre front-end engineering and design aspects of the field. Production will be undertaken through a total of 17 development wells, including production wells, water injection wells and gas injection wells clustered around two drill centres.
Clustering of the wells around the drill centre will help reduce the number of umbilicals, risers and flowlines required.
The wells will be connected to a spread-moored floating production, storage and offloading (FPSO) vessel through subsea umbilicals, risers and flowlines ranging from 3.6km to 6.6km in length. An existing double-hull very large crude carrier will be converted for use at the field.
The FPSO vessel will include topside facilities, which can process fluids from the production wells at the rate of 100,000 barrels of oil a day (bopd). The hull of the FPSO will have the capacity to store 1.6 million barrels of processed crude oil, which will be periodically offloaded onto conventional tankers.
Drilling of the development wells is expected to commence in early-2017 followed by the installation of the subsea facilities and FPSO. Two drill ships are expected to be used simultaneously to drill the development wells.
Seismic data specialist Spectrum supplied 2D seismic data for evaluating the Liza prospect.