Seismic challenge for Oil India at Nahorkatiya

Vol 16, PW 16 (07 Mar 13) Exploration & Production
     

Oil India is gearing up for a challenging onland 3D shoot at one of its oldest producing fields: Nahorkatiya in northeastern Assam.

Expect a tender by the end of this month (March) to shoot 250-sq km 3D at Nahorkatiya and 250-sq km 3D at its Dikom Chabua field, also in Assam. Oil India wants to shoot high density 3D to get higher resolution data and has received EoIs from 10 potential bidders, among them Shiv Vani, Geofizyka Torun, Asian Oilfield Services and Alpha Geo.

“We are evaluating EoIs,” confirms a company source. Shooting 3D at the pre-NELP Dikom Chabua field should be easy given the flat terrain.

But it's a different story at Nahorkatiya. Discovered in 1953, the field contains the wide riverbed of the river Buri Dihing in addition to swamps, oil and gas production installations, and village houses.

Producing 4200 b/d, the field has over 300 wells drilled since 1950. It will be difficult to shoot conventional seismic using dynamite and geophones because of the many oil and gas installations.

Conventional 3D will have large gaps between shots because of these oil and gas structures. “We are still evaluating what's the best 3D technology for this block," says Oil India.

"Bidders have suggested technology in their EoIs." Oil India plans to award the contract by June so the selected company can mobilise by October.

"We want to begin shooting 3D in November after the monsoon," we are told, “and complete acquisition by May next year (2014)." Oil India will float a separate tender by October this year to process and interpret the 3D.