* U.S. shale output to hit record 7.7 mln bpd in Nov - EIA
* U.S. crude inventories likely to increase - Reuters poll
* Iran exports 1.33 mln bpd of crude in Oct. 1-14 - Refinitiv
* OPEC says global spare capacity shrinking (Updates detail, prices, comment; paragraphs 1-5)
LONDON, Oct 16 (Reuters) - Oil prices fell on Tuesday on evidence of higher U.S. oil production and increasing U.S. crude inventories, but reports of a fall in Iranian oil exports helped limit losses.
Brent crude was down 50 cents a barrel at $80.28 by 0900 GMT. U.S. light crude was 50 cents lower at $71.28.
"Shale oil production continues unabated in the United States," said Carsten Fritsch, commodities analyst at Commerzbank. "Rising U.S. oil production is one key reason why the global oil market is likely to be amply supplied next year."
Oil production from seven major U.S. shale basins is expected to rise by 98,000 barrels per day (bpd) in November to a record of 7.71 million bpd, the U.S. Energy Information Administration (EIA) said.
The largest change is forecast in the Permian Basin of Texas and New Mexico, where output is expected to climb by 53,000 bpd to a fresh peak of 3.55 million bpd.
U.S. oil production has increased steadily over the last five years, reaching a record high of 11.2 million bpd in the week to Oct. 5. But infrastructure has not kept pace with rising output, filling domestic tanks.
"Once pipelines and oil terminals are built connecting the Permian to the U.S. Gulf Coast, then there will be a big step up in U.S. crude oil exports," Harry Tchilinguirian, oil strategist at French bank BNP Paribas told Reuters Global Oil Forum.
U.S. crude stockpiles are expected to have risen last week for the fourth straight week, by about 1.1 million barrels, according to a Reuters poll ahead of reports from the American Petroleum Institute (API) and the U.S. Department of Energy's Energy Information Administration (EIA).
API data are due at 4:30 p.m. EDT (2030 GMT) with the EIA at 10:30 a.m. EDT (1430 GMT) on Wednesday.
Balancing the U.S. data were reports that Iranian exports of crude oil are falling faster than expected ahead of new U.S. sanctions on Tehran from Nov. 4.
In the first two weeks of October, Iran exported 1.33 million bpd of crude to countries including India, China and Turkey, according to Refinitiv Eikon data. That was down from 1.6 million bpd during the same period in September.
The October exports are a sharp drop from the 2.5 million bpd in April before U.S. President Donald Trump withdrew from a multilateral nuclear deal with Iran in May and ordered the re-imposition of sanctions.
Meanwhile, OPEC Secretary General Mohammad Barkindo said on Tuesday that global spare oil capacity was shrinking, adding that producers and companies should increase their production capacities and invest more to meet current demand.
With the world's only sizable spare oil output capacity, Saudi Arabia is expected to export more to offset the loss of Iranian oil supply from the sanctions.
Tension over the disappearance of a Saudi Arabian journalist Jamal Khashoggi in Turkey also remain.
Saudi Arabia has denied it was responsible for the disappearance of Khashoggi. (Reporting by Jane Chung; editing by Joseph Radford and David Evans)