CREATE TABLE table_38840 ("Name" TEXT, "Type" TEXT, "Entered service" TEXT, "Water depth" TEXT, "Location" TEXT)

What is the water depth of Sedco 702, located in Nigeria?
SELECT "Water depth" FROM table_38840 WHERE "Location" = 'nigeria' AND "Name" = 'sedco 702'
SELECT "Water depth" FROM "table_38840" WHERE "Location" = 'nigeria' AND "Name" = 'sedco 702'