Dec 27 (Reuters) – Venezuela this year almost doubled its oil production from last year’s decades-low as its state-owned company struck deals that let it pump and process more extra heavy crude into exportable grades. The surprising reversal began as state-run Petroleos de Venezuela, known as PDVSA, won help from small drilling firms by rolling over old debts and later obtained steady supplies of a key diluent from Iran. The two lifted output to 824,000 barrels per day (bpd) in November, well above the first three-quarters of the year and 90% more than the monthly average a year earlier.Whether it can continue to ramp up production is unclear. Years of unpaid bills, mismanagement and, more recently, U.S. sanctions here have cut its access to specialized drilling equipment and foreign investment. The sanctions have also limited its customers to firms with no track record of trading.PDVSA’s latest gains – including reaching 1 million barrels of daily output for the first time in nearly three years, which Oil Minister Tareck El Aissami described in a Christmas day message as a “great victory” – still fall short of current management’s 2021 goal of producing 1.28 million bpd. Workers in producing regions say the reopening of oilfields continues and more flow stations are expected to restart. However, oil experts said PDVSA has done all it can and further gains might be capped by a lack of additional rigs and functioning upgraders for its tar-like crude.“Base production in 2021 was way below PDVSA’s production capacity,” said Francisco Monaldi, director of the Latin American Energy Program at Rice University’s Baker Institute in Houston. “We are reaching that capacity now. To see an output increase during 2022, investment in new wells and upgrading infrastructure is needed,” he added. The main turning point came from a swap deal between state-run firms PDVSA and National Iranian Oil Company (NIOC) that began in September. It proved crucial for generating exportable grades from the extra-heavy crude produced at Venezuela’s top region, the Orinoco Belt. Hard-currency proceeds from domestic fuel sales and higher oil exports to Asia have also allowed PDVSA to amortize some debts with service companies and settle overdue debts with a promise of future work and permits that allowed some domestic firms to operate workover rigs. A few service companies also accepted payments in kind, mainly oil byproducts and residual fuel later sold domestically and overseas, according to people familiar with the matter. By mid-December, there were a total of 47 workover and maintenance rigs active in the Orinoco Belt and 29 more in other regions, according to a PDVSA internal document seen by Reuters. That same report showed 19 others that were inactive. No active drilling rigs, which are needed for building output capacity, were reported.PDVSA did not reply to a request for comment. The U.S. Department of Treasury, which enforces sanctions on PDVSA, did not immediately reply to a request for comment.