About 77 pct of Songa shareholders have so far accepted deal. Transocean, one of the world's biggest drilling rig operators, has agreed a deal to buy Norwegian competitor Songa Offshore for 9.1 billion Norwegian crowns ($1.1 bln), the two companies said on Tuesday. The deal, which would be mostly paid for in shares and convertible bonds, would strengthen Transocean's position in offshore drilling as Songa is Norwegian oil major Statoil's largest drilling service provider. The offer values Songa shares at 47.50 Norwegian crowns each, a 39.7 percent premium over Monday's closing price. Shares in Songa surged 31 percent on news of the deal, which needs the backing of at least 90 percent of Songa shareholders. So far about 77 percent of shareholders have agreed to the offer, the company said.