In an action against two banks in alleging a superior right to continue to use the gas in a natural gas storage facility, summary judgment for defendants is affirmed in part where the district court was correct that defendant retained a valid security interest in the gas under the operative agreements, and the plaintiffs' refusal to return the gas thereafter constituted conversion. However, the judgment is reversed in part where defendants could identify no special circumstances sufficient to overcome the presumption in favor of adjudication of the Tort and Contract Claims in the Texas District Court, where the action was originally filed prior to transfer.