ING Barings has raised its ratings of the shares of several oil and gas companies. ING raised Burlington Resources to strong buy from hold, Transocean Offshore to strong buy from buy and Ocean Energy Inc. to buy from hold. On Transocean, analyst Stephen Gengaro wrote: "We believe the stock has lagged the group because of the relatively high level of contract rollovers over the next six months, which includes some of the company's high-specification semis currently working at high day rates. "While these rollovers will likely keep pressure on earnings over the next several quarters, we do not expect the company to sign any long-term contracts…