CVX market cap is approximately $199 B. COP market cap is approximately $55 B. A non-cash merger between CVX & COP would be valued at approximately $254 B w/ current pre-merger CVX shareholders owning approximately 78 percent of the merged entity. There would be some value-adding synergies attributed to the no-cash merger....yielding billions of dollars of value essentially cost free....
Other candidates may be OXY or Marathon. All are essentially pure upstream E&P companies. Any could be swallowed up by CVX w/ a lot of cost savings in synergies, downsizing and streamlining.