BP leaving the oil business has led a rally in oil and gas stocks. Production capacity has to be reduced, so Chesapeake's bankruptcy helped a little, and BP helps more.
The destruction of BP was former CEO Lord John Browne, Baron of Madingley who fired more than half of BP's engineering staff to save money, deciding BP would make more money "doing deals".
In this purge BP lost their institutional memory for the oil and gas business which directly led to the "Deepwater Horizon" disaster as they made bizarre cost-cutting decisions, such as directing Halliburton to use a small fraction of the positioners required while drilling, and God knows Halliburton has no institutional memory, morals or desire to do anything other than what the customer directs them to do.