Sprinkle scallops with salt and pepper. Heat 1 1/2 teaspoons oil in a 10-inch cast-iron or heavy skillet over high heat until very hot (about 3 minutes). Add half of scallops; cook 2 minutes on each side or until browned. Remove scallops from pan; keep warm. Repeat procedure with 1 1/2 teaspoons oil and remaining scallops. Remove scallops from pan.
Stir in port and lemon juice, scraping pan to loosen browned bits. Add scallops, 3 tablespoons parsley, and garlic; saute 30 seconds over high heat. Serve scallops over rice. Sprinkle with 1 tablespoon parsley.