...appeal, we consider whether the Superior Court properly applied the doctrine of estoppel by deed to conclude that an oil and gas lease between Appellee, Anadarko E. & P. Co., L.P. (“Anadarko”), and..., asserting that Appellants were estopped, both by their contractual promises and by the doctrine of estoppel by deed, from denying that the Lease grants Anadarko 100% of the oil and gas rights to the...proportion of such oil and gas rights owned by LESSOR.” Lease at 2 § C.3 (R.R. at 11A). Moreover, the trial court determined that, under the doctrine of estoppel by deed, Appellants' subsequent...