FACTBOX-Oil service, petrochemical assets in Venezuela

June 6 (Reuters) - Venezuela's National Assembly is readying a law to nationalize petrochemical projects in the latest move to seize strategic industries as part of President Hugo Chavez's socialist revolution in the OPEC country.

Lawmakers passed a law this year that led to the nationalization of dozens of smaller oil service companies. Larger companies were excluded but many are owed huge debts by state oil company PDVSA, prompting some of them to idle rigs. Analysts say that could trigger disputes and countermeasures by the government.

The government has not said what assets may be in its sights next. Here are some of the oil service and petrochemical projects in Venezuela.

* Japan's Mitsui (8031.T) has a 15 percent stake in the Propilven chemical complex in El Tablazo in northwestern Zulia state. State petrochemicals firm Pequiven says it already holds a 49.4 percent stake in the project.

* Japan's Mitsubishi Corp. (8058.T) and Mitsubishi Gas Chemical (4182.T) both hold 23.75 percent stakes in Metor methanol operations in Anzoategui state with Pequiven, the company website says.

* An affiliate of U.S. chemical maker FMC Corp (FMC.N) has a 33.3 percent stake in the Tripoliven plant in Carabobo state. According to the company, the plant is owned by Pequiven, Valquimica SA and FMC Foret, Spanish subsidiary of the U.S. corporation.

* Privately held Koch Industries owns 35 percent of FertiNitro, one of the world's largest nitrogen-based fertilizer plants, in partnership with Pequiven, which owns 35 percent, and Snamprogetti, an affiliate of Italy's Saipem SpA (SPMI.MI), which holds 20 percent.

* Schlumberger Ltd (SLB.N): The world's largest oil service company is also the principal provider of services in Venezuela including drilling, measurement and well services designed to boost output of operations. Sources say PDVSA's debts with Schlumberger are the largest among the service companies operating in the country.

* Halliburton Co (HAL.N): A major player in Venezuela's oil services market, Halliburton provides products such as drilling fluids and a range of oil well services. PDVSA owes it hundreds of millions of dollars in debts. Supporters of leftist Chavez have frequently insulted the company for its association with former U.S. Vice President Dick Cheney despite it being a key PDVSA contractor.

* Petrex: Owned by a division of Italy's Eni (ENI.MI), Petrex operates around 30 land rigs throughout Venezuela, mostly concentrated in the eastern region.

* Baker Hughes (BHI.N): The world's third-largest oil services company provides a range of oil field and oil well services in Venezuela.

* San Antonio Internacional: A land-based driller with a heavy presence in Latin American oil operations and a key driller in Venezuela.

* Other contractors operating in Venezuela include Danish shipping and oil group A.P. Moller-Maersk (MAERSKb.CO), BJ Services Co (BJS.N) and Weatherford International Ltd (WFT.N).

(Reporting by Caracas newsroom; Editing by Eric Beech)