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Offshore / Upstream

Oil and gas developments are evolving from conventional to unconventional resources for onshore, and from shallow to deepwater for offshore. Offshore developments are shifting from shallow water areas such as Middle East, the North Sea, South East Asia, North America and Australia to deepwater areas like Africa, Brazil, the Gulf of Mexico and the Artic. The development of methane hydrate reserves around areas of deepwater off the coast of Japan are also drawing increasing global attention.

Life cycle of subsea development

Offshore developments require a long period of time (5-15 years) from exploration to the start of production. A typical development process consists of four (4) stages. “Exploration” is the 1st stage that involves the discovery of oil or gas prospects through geophysical and geological study and exploration. “Development” is the 2nd stage that assesses the recoverable reserves by drilling some appraisal wells and analyzing the data obtained from the appraisal well. At this time, the operator will determine a development plan detailing key development milestones. Through conducting the following sequential studies; feasibility study, concept select study and FEED, the operator will consider the continuation of the project at a stage gate called ‘final investment decision’ (FID). Following approval of FID, the “Execution” stage of the project is conducted to execute the detailed Engineering, Procurement, Construction and Installation (EPCI). Upon completion of construction and production startup of the development the operator will move into the “Life of field” stage of thee development concerned with ongoing asset operations and integrity management.


Under the lifecycle mentioned above, offshore oil and gas fields are developed through aspects including reservoir geology, drilling, well completion, environmental assessments, facility design, installation and operations. Chiyoda has efficiently collaborated with Xodus in technical expertise and engineering consultancy and provides offshore development support service for every step of the process.