Expect attractive seismic OBN tender in Feb

Vol 19, PW 9 (14 Jan 16) Exploration & Production

ONGC is expected to issue a more attractive tender in February to shoot Ocean Bottom Node (OBN) 3D seismic on the west coast after accepting a raft of useful suggestions from disgruntled contractors.

As the name suggests OBN involves placing highly sensitive sensor 'nodes' on the seabed to record seismic. ONGC abandoned an earlier OBN tender after receiving only one bid from Hind Offshore on September 7, 2015.

Three months later on December 9, 2015 it called a day-long 'by invitation only' meeting to explore how to motivate more companies to bid. Six attended: SMNG-Center; FairfieldNodal; Marine Geology Services (MGS); Geokinetics; Fugro and CGG joint venture Seabed Geo Solutions; and Hind Offshore.

A surprise absentee was SAExploration which bought documents for the last tender but did not bid. Led by executive director USD Pandey and general manager Mahendra Pratap, ONGC outlined the project to shoot and process 4C (four component) 3D OBN over 600-sq km in 3-40 metre water depths at the producing pre-NELP Tapti Daman block.

ONGC then heard individual closed-door presentations. All wanted ONGC to relax its condition that bidders have shot a similar 600-sq km OBN assignment in the past five years.

Anyone with 300-sq km OBN experience should be eligible, they argued. "Hardly any companies have shot and processed 600-sq km," explains a participant.

"You might get just one or two."

One participant tells us ONGC should allow work to be completed across two seasons not one. "Strong sea currents result in idle crew and equipment for up to 10 hours a day," he says. "ONGC should understand this and spread the job over two seasons." Another participant said no major contractor has vessels that operate in water depths below 20 metres. "But it's possible to do this job if ONGC spends money and gives us time," he adds. Some say ONGC should increase the 'bin' size (survey areas are subdivided into 'bins') of its survey specs from 12.5 x 12.5 metres to 12.5 x 25 metres. "A larger bin size needs fewer nodes and reduces costs without affecting data quality," says a source. "Some estimate this job needs 500 nodes, others 4000. I think it can be done with 1000. It's like choosing between a house with regular fittings and one with fancy expensive fittings." Four component (4C) seismic uses geophones with four components to record four different sounds: a 'p' sound, two 's' sounds and one 'water' sound. This makes it easier to isolate the water sound.

Expect attractive seismic OBN tender in Feb

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