NEW YORK (CNN/Money) - Lower oil prices could help keep the positive momentum going when Wall Street begins a new trading week Monday.

Early Monday, Nasdaq and S&P futures were solidly higher.

After settling Friday above $50 a barrel for the first time, oil prices eased early Monday amid an easing of tensions in Nigeria. U.S. crude futures fell 57 cents to $49.55 a barrel in electronic trading, while Brent oil futures slipped 63 cents to $45.99 a barrel in London.

The Dow Jones industrial average finished a positive week Friday with a 1.1 percent gain, while the Nasdaq composite index soared 2.4 percent (see chart for details).

Asian-Pacific stocks were buoyant Monday, reacting in part to Wall Street's strong Friday showing, with the Nikkei index up 2.7 percent in its biggest one-day gain since June. European markets showed solid gains early in the session. (Check the latest on world markets)

Among U.S. stocks trading in Europe, Amgen (AMGN: Research, Estimates) rose more than 1 percent. The biotech developer said an osteoporosis drug under development increased bone density in post-menopausal women in a small trial.

For details of Friday's rally, click above.

Wal-Mart Stores (WMT: Research, Estimates) was slightly higher. The No. 1 retailer's preliminary September same-store sales came in at the low end of expectations with a gain of 2.3 percent.

Treasury prices fell in early trading, sending the 10-year note yield up to 4.20 percent from 4.19 percent late Friday. The dollar advanced against the yen and euro. Gold was slightly lower.

The report for August factory orders is due after the markets open. Economists surveyed by Briefing.com expect a 0.1 percent increase, compared with a 1.3 percent rise in July.