DUPONT <DD> UNIT RAISES CRUDE OIL PRICES Conoco Inc, a subsidiary of DuPont Corp, said it was increasing its contract prices for crude oil between 10 cts and one dlr a barrel, effective today. Conoco said the increase brings its price for the U.S. benchmark crude West Texas Intermediate to 17.50 dlrs a barrel, up one dlr. South Louisiana Sweet, also up one dlr, is now 17.85 dlrs. West Texas Sour was up 10 cts to 16.60 dlrs a barrel. Conoco was the last company to raise prices following a series of increases initiated last week by Sun Co <SUN>, which reversed the posted price cuts made at the end of February.