A method comprising: running a lower completion assembly (20, 650, 750, 850, 900) into a well in a single trip, the lower completion assembly (20, 650, 750, 850, 900) comprising a screen (100, 674, 684, 754, 860), a first valve (150, 664, 910, 985) and a second valve (110, 400, 664, 668, 682, 862); performing a gravel packing operation using the assembly, the performing comprising running a service assembly into the lower completion assembly (20, 650, 750, 850, 900) to operate the first valve (150, 664, 910, 985); removing the service assembly from the well; and subsequently installing an upper completion assembly (800, 980) in the well, the installing comprising enabling remote control of the second valve (110, 400, 664, 668, 682, 862) to regulate production of fluid from the well, characterized by: performing the gravel packing operation after the running of the lower completion assembly (20, 650, 750, 850, 900) into the well; the performing further comprising communicating a gravel packing slurry and running the service assembly into the lower completion assembly (20, 650, 750, 850, 900) to operate the first valve (150, 664, 910, 985) to communicate fluid from the gravel packing slurry into a central passageway of the lower completion assembly (20, 650, 750, 850, 900); running an isolation seal assembly (700, 760, 960, 986) into the lower completion assembly (20, 650, 750, 850, 900) to prevent leakage from occurring through the first valve (150, 664, 910, 985) after a gravel packing operation; and running a shifting tool at the lower end of the isolation seal assembly (700, 760, 960, 986) into the lower completion assembly (20, 650, 750, 850, 900) to open the second valve (110, 400, 664, 668, 682, 862). running a lower completion assembly (20, 650, 750, 850, 900) into a well in a single trip, the lower completion assembly (20, 650, 750, 850, 900) comprising a screen (100, 674, 684, 754, 860), a first valve (150, 664, 910, 985) and a second valve (110, 400, 664, 668, 682, 862); performing a gravel packing operation using the assembly, the performing comprising running a service assembly into the lower completion assembly (20, 650, 750, 850, 900) to operate the first valve (150, 664, 910, 985); removing the service assembly from the well; and subsequently installing an upper completion assembly (800, 980) in the well, the installing comprising enabling remote control of the second valve (110, 400, 664, 668, 682, 862) to regulate production of fluid from the well, characterized by: performing the gravel packing operation after the running of the lower completion assembly (20, 650, 750, 850, 900) into the well; the performing further comprising communicating a gravel packing slurry and running the service assembly into the lower completion assembly (20, 650, 750, 850, 900) to operate the first valve (150, 664, 910, 985) to communicate fluid from the gravel packing slurry into a central passageway of the lower completion assembly (20, 650, 750, 850, 900); running an isolation seal assembly (700, 760, 960, 986) into the lower completion assembly (20, 650, 750, 850, 900) to prevent leakage from occurring through the first valve (150, 664, 910, 985) after a gravel packing operation; and running a shifting tool at the lower end of the isolation seal assembly (700, 760, 960, 986) into the lower completion assembly (20, 650, 750, 850, 900) to open the second valve (110, 400, 664, 668, 682, 862). performing the gravel packing operation after the running of the lower completion assembly (20, 650, 750, 850, 900) into the well; the performing further comprising communicating a gravel packing slurry and running the service assembly into the lower completion assembly (20, 650, 750, 850, 900) to operate the first valve (150, 664, 910, 985) to communicate fluid from the gravel packing slurry into a central passageway of the lower completion assembly (20, 650, 750, 850, 900); running an isolation seal assembly (700, 760, 960, 986) into the lower completion assembly (20, 650, 750, 850, 900) to prevent leakage from occurring through the first valve (150, 664, 910, 985) after a gravel packing operation; and running a shifting tool at the lower end of the isolation seal assembly (700, 760, 960, 986) into the lower completion assembly (20, 650, 750, 850, 900) to open the second valve (110, 400, 664, 668, 682, 862).