WASHINGTON  People and businesses seeking a lump-sum settlement from BP’s $20 billion oil spill compensation fund will most likely have to waive their right to sue not only BP, but also all the other major defendants involved with the spill, according to internal documents from the lawyers handling the fund.

The documents  which include e-mails, draft and final versions of the protocols, claims forms and legal notes about the administration of the fund  provide the first definitive picture of who will be paid by the $20 billion fund, and how and when.

They also shed new light on the components of the payment plan that are likely to stir controversy, including the fund’s emphasis on geographic proximity as a determining factor for eligibility.

The fund is being administered by a prominent Washington lawyer, Kenneth R. Feinberg, who declined to be interviewed about the documents but verified their authenticity.