THE Nigerian government on Wednesday signed a $1-billion oilfield development agreement with Anglo-Dutch oil giant Shell. The EA/EJA oil field, estimated to have reserves of 350-million barrels, is expected to go into operation in the second half of next year. The accord between the Nigerian National Petroleum Corporation and Shell Petroleum Development Company is aimed at providing an alternative source of funding to the joint ventures beside the traditional cash calls, officials said. Shell will invest 77,14%, Italy’s Agip 12,86% and Elf 10%.