Oil industry's cost dilemma

A confession is in order: Although the concept of outsourcing has been explained to me many times, I have never been fully convinced of its logic. Somewhere in the explanation there has always been a justification of outsourcing along the lines that "divestment of noncore activities" is imperative. It is at this point that I have always come unstuck. Call me simple if you like, but I have always had the idea that, for a petroleum company, anything involved in finding and exploiting oil and gas