CARACAS, Venezuela—The government of this oil-rich but struggling country, looking for ways to circumvent U.S. sanctions, is telling oil traders that it will no longer receive or send payments in dollars, people familiar with the new policy have told The Wall Street Journal.

Oil traders who export Venezuelan crude or import oil products into the country have begun converting their invoices to euros. The state oil company Petróleos de Venezuela SA, known as PdVSA, has told its private joint venture partners to open accounts...