(appellate court affirmed trial court’s cancellation of an oil and gas lease as to 150 acres of a 160-acre tract; lessee’s predecessors had secured the lease on the 160-acre parcel in 1950, but had only developed 10 acres; trial court’s finding that lessee had breached its implied covenant for reasonable exploration and development was supported by substantial evidence; lessee’s claim that it could not conduct the 3D seismic study required for future development because the adjacent landowner blocked its efforts was unavailing because lessee had undertaken no exploration or production for nearly 60 years; trial court properly considered that termination of the lease would probably allow landowner to conduct further development; trial court did not err in ordering lease cancellation instead of a cancellation conditional upon future development; because the lessee had no plans for further development in the foreseeable future, a conditional remedy would not have been practical or adequate).