OREANDA-NEWS. ExxonMobil' plan to start drilling this month offshore Guyana sparked a reaction from Venezuela which claims sovereignty over the maritime area.

Venezuela?s foreign minister Delcy Rodriguez expressed her government?s opposition to the US major?s drilling plan in a letter sent directly to ExxonMobil?s Guyana office last month.

"The written communication signed by minister Rodriguez was sent to the director of ExxonMobil?s Guyanese affiliate Jeff Simon, expressing that the Boliviarian Republic of Venezuela opposes the delivery of a unit from Exxon to continue the exploration of an oil well on a concession awarded by Guyana," a Venezuela foreign ministry official told Argus today.

Guyana has urged neighboring Venezuela to refrain from interfering with ExxonMobil?s offshore exploration, Guyana's foreign ministry said yesterday.

Guyana has asked Venezuela to "desist from taking any actions that could only result in the stymying of the development of Guyana and its people and that would be in contravention of international law," the ministry said.

ExxonMobil did not comment on the Venezuelan letter. "Esso Exploration and Production Guyana Limited, an affiliate of ExxonMobil, plans to start drilling a deepwater exploration well on the Stabroek Block approximately 120 miles offshore Guyana in March 2015. Border issues are a matter for governments to resolve through bilateral discussions and appropriate international organizations. We are operating the Stabroek Block offshore Guyana under license from the government of Guyana," ExxonMobil said.

Stabroek covers 26,806km? (10,350mi2) in water depths of 200-3,000m (656-9,843ft), according to Guyana's state-run mining and energy agency GGMC.

ExxonMobil, which operates the block with a 75pc stake, will use the Deepwater Champion rig on the site. Shell holds the remaining 25pc in the block.

The block lies in the resource-rich Essequibo that covers the western two-thirds of Guyana.

Venezuela?s sovereignty claim has prevented the two countries from defining their maritime boundary.

The last flare-up in relations occurred in October 2013, when the Venezuelan navy seized the Teknik Perdana vessel, alleging that it had entered into Venezuela's maritime territory, an assertion that Guyana denied.

The research vessel had been working in the Roraima block on behalf of US independent Anadarko, and was released after eight days.

Stabroek is part of the Guianas Shield that runs from Venezuela to French Guiana, and which the US Geological Survey estimates could contain technically recoverable oil reserves of over 13.6bn bl and natural gas reserves of 21.2 trillion ft3.

Guyana does not produce any oil or gas, and meets demand of around 10,500 b/d with imports from Venezuela and Trinidad.

Guyana is a member of PetroCaribe, through which Venezuelan state-owned PdV supplies subsidized crude oil and refined products to neighboring countries.

The Venezuelan government already sees ExxonMobil as a nemesis. The US major was awarded \$1.6bn in compensation from Venezuela last year by the International Centre for Settlement of Investment Disputes (Icsid) for the 2007 expropriation of its Venezuelan assets. Caracas subsequently obtained a review of the Icsid decision, postponing the award.

The tensions have surfaced against a backdrop of increasingly virulent Venezuelan accusations that Washington is engaged in a conspiracy to topple President Nicolas Maduro and is waging an "economic war" on the country. Washington regularly dismisses the Venezuelan charges.

On 28 February Maduro told a pro-government rally that the US embassy in Caracas will be ordered to reduce its personnel and US citizens will require visas to enter the country, as Venezuelans currently require for travel to the US.

The Venezuelan government also barred senior US officials from entering the country because of "acts of terrorism", in a response to US targeted sanctions on Venezuelan officials imposed last year.