(Adds Pemex's average crude output and exports in July)
MEXICO CITY Aug 22 (Reuters) - Mexico's national oil company Pemex said on Friday it has lowered its crude oil output forecast for 2014 to 2.35 million barrels per day (bpd) as it sought to improve the way it measures production.
A company spokesman said that the new estimate did not mean that the company will produce less crude oil but instead that production will now be measured more accurately.
The new figure aims to strip out water mixed into oil deposits and other "distortions" that inflated reported crude output in the past, Pemex said.
The revised estimate would be a 30 percent slide compared with output of 3.38 million bpd reported in 2004.
On a conference call with investors last month, Pemex's exploration and production chief revised down the company's forecast for output this year to 2.44 million bpd.
The Mexican oil company has recently faced accusations of inflating crude production statistics, which some analysts said could lead to charges of misleading investors.
Also on Friday, Pemex reported crude production of 2.39 million bpd for July. That was the lowest monthly level since October 1995, when production was down by more than 800,000 bpd due to disruptions caused by Hurricane Roxanne.
Crude exports for July averaged 1.02 million bpd, the lowest level since May 2013.
Mexico is the world's tenth-biggest crude producer, but it is forced to import much of its natural gas and gasoline due to insufficient domestic production.
Pemex hit peak crude production in 2004, thanks to surging production from the company's Cantarell field, one of the world's largest, when it was discovered in 1976.
But crude output has fallen each year since the 2004 peak.
Mexico's government relies on oil revenues to fund about a third of the federal budget.
President Enrique Pena Nieto signed into law this month the final elements of a sweeping energy reform aimed at luring billions of dollars in private investment to the sector.
The reform ended Pemex's 75-year monopoly and the company will now be able to enter into first-ever joint ventures with oil majors. Private and foreign oil companies will also be able to operate fields on their own for the first time in decades.
Last week, Pemex Chief Executive Officer Emilio Lozoya said he expects Pemex to produce about 2.8 million bpd by 2018. (Reporting by Alexandra Alper and David Alire Garcia; Editing by Lisa Shumaker)