Mix 2 cups self-rising flour, oil, and water together in a bowl until pie crust dough is well-mixed; divide into 2 balls. Roll each ball between 2 pieces of waxed paper until flattened and about 9 inches in diameter. Turn 1 piece of dough over pie dish and peel off top piece of waxed paper. Trim crust if needed. Set remaining dough aside.
Combine blueberries, sugar, 1/4 cup all-purpose flour, lemon juice, and salt together in a bowl until evenly mixed; pour into the pie crust. Cover blueberry filling with remaining dough, crimping the edges together. Arrange butter cubes on top crust.
Bake in the preheated oven until filling is thick and crust is golden brown, about 50 minutes.