By Ana Mano

SAO PAULO, Jan 18 (Reuters) -

Global grain traders Cargill and Viterra appear as charterers of two vessels to be loaded with Brazilian soybeans for delivery in Argentina over coming weeks, according to shipping data.

Cargill's Interlink Fortuity vessel is expected to arrive on Jan. 25 at the port of Santarem in northern Brazil and set sail on Feb. 5, loaded with a 27,000-tonne cargo for Argentina, shipping data show.

Viterra's Indigo Garland is due to arrive in three days at the same port. It will set sail on Feb. 8 with a 44,000-tonne soy cargo also to be delivered in Argentina, according to shipping schedules.

Cargill declined to comment. Viterra did not immediately reply to comment requests on the export deals.

Brazilian soy shipments to Argentina usually come later in the year and serve the purpose of supplying Argentina's soy processors at the peak of the inter-harvest period. Both countries are big soybean growers, with Brazil being the world's biggest exporter of the raw beans and Argentina the Number 1 soymeal and soyoil exporter.

The timing of the shipments and the port of departure are both atypical, according to analysts and traders.

Normally, Brazilian soy is sent via river on barges from Murtinho port in Mato Grosso do Sul, and arrive at Argentina's Rosario hub directly, they said.

Last week, a Brazilian trade group representing global grain merchants confirmed the sale of Brazilian soybeans to Argentina after rumors about unusual cargos.

Anec said that Brazilian supplies are needed after a spate of Argentine soy sales in the final quarter of the year, which lowered local stocks and could leave Argentina's soybean processors uncovered at a time of high crushing margins.

The expectation that a brutal drought will reduce Argentina's domestic soy production in 2023 is also driving Brazilian soy sales to its neighbor, Anec said. (Reporting by Ana Mano Editing by Marguerita Choy)