Deepwater exploration on KG-D6 oil and gas fields in the Krishna-Godavari basin of the Bay of Bengal looks as if it were straight out of a science fiction novel. Thanks to the advanced equipment and technologies, Reliance Industries is all set to commission a full production system?from discovery to production?of a deepwater oil and gas facility .
In the year 2002 when Reliance Industries struck gas in the KG-D6 block, which was awarded under the National Exploration Licensing Policy-I (NELP I), it was the world?s largest discovery of the year. Reliance Industries is all set to bring this discovery on stream within six years, as against the norm of 8 to 10 years .
Technically, it is not a child?s play to develop such a mammoth infrastructure, that too in the Bay of Bengal, which is notorious for frequent cyclonic storms and rough weather. Reliance Industries has made an overall investment of over $5 billion and brought in some of the most advanced equipment and technologies to develop the KG-D6 oil and gas fields. These include floating production storage and offloading vessel (FPSO) and the control raiser platform (CRP), which are located about 25 km from the shore. The project is claimed to be world?s largest greenfield offshore oil and gas infrastructure. The combined production is to the tune of 5,50,000 BOE (barrel oil equivalent) per day.
KG-D6 claims to have bagged in many firsts. One of them was the FPSO facility, which is an oil tanker converted into a mobile oil production facility. The control and riser platform is the key control area which regulates the pressure of gas before it is transported to the onshore terminal.
Deepwater environments are among the harshest environments for oil and gas production facilities anywhere in the world. According to Reliance officials, typical challenges associated with deepwater explorations are soil erosion affecting stability of equipment at the seabed, corrosion of equipment, current loads impacting equipment at seabed and flow assurance of fluids due to the potential of fluids being converted into crystalline solids called hydrates that can act as plugs and choke the fluid flow.
To add to these challenges, the KG-D6 oil and gas fields are located at water depths ranging from 600 meters and extending up to 2,000 meters. These make them one of the world?s deepest and far beyond the range of human diver depths, which are at the most up to 100 meters.
These engineering challenges are further exacerbated by the challenges of equipment installation due to rough weather conditions of the Bay of Bengal, which is among the harshest operating environments in the world. Storms, cyclones and waves that swell up to 20 meters and currents of over 4 knots are a permanent fixture for most part of the year, barring a fair weather window of less than four months, typically from December to April.
The remote location of KG-D6 and lack of adquate infrastructure were key factors that had to be kept in mind at the project design stage. In such a scenario, the deployment of cutting edge technology and system reliability were identified as a ?must have? for the success of the project.
The KG-D6 facility can be divided into three main segments?sub-sea facilities, the FPSO and control and riser platform and on-shore facilities. The gas reservoirs, which lie several thousand meters below the seabed had to be characterised using three dimensional seismic technology. Multi-disciplinary teams comprising of geoscientists and reservoir engineers were engaged in characterising and modeling them. Primary among them were virtual reality centres based on 3D immersive technology that greatly enhanced the understanding of these deep water reservoirs.
Drilling was undertaken by deep water rigs and their operations monitored through real time operation centres that enable accuracy of targeting the reservoirs during drilling as well as live monitoring of the well construction activities. All sub-sea equipment was engineered and fabricated keeping in mind the physical challenges for equipment at the seabed.
Over 1,10,000 metric tonne of steel and over 2,400 line kilometers of flow lines were lowered into the seabed by highly specialised vessels.These not only have heavy lift and installation capabilities, but can also withstand the turbulent conditions of the east coast. Almost 80 marine vessels equivalent to the naval fleet sizes of several countries were operating at any given time in about 400 square kilometers?all managed through real-time operations centres and control rooms.
More than a kilometer deep in the seabed and up to 50 km away from the onshore terminal, there are wide array of manifolds tied to production systems and gas producing wells through robotic remote operated vehicles (ROVs). These ROVs are controlled from the topside of a marine vessel and are like true workhorses that helped Reliance engineers and technicians set up this deepwater production facility.
The entire field is controlled via power and fibre optic communication umbilicals and operated via a distributed control system (DCS) in the control centre. This enables a round-the-clock watch on the entire production facility from wells below the seabed, to equipment and flowlines on the seabed and production spanning across individual wells to overall production from the field. Therefore, to say that the control centre of the Reliance facility resembles a spaceship would not be out of context.
