UPDATE 6-Oil falls on rising supply, central bank fears
* Reuters poll forecasts increase in U.S. crude stockpiles
* Central Banks could start tightening monetary policy
* OPEC trims 2013 world oil demand growth forecast
* Weaker Chinese economy continues to weigh on oil
(Updates prices, changes byline, dateline (pvs London)
NEW YORK, June 11 (Reuters) - Brent crude tumbled on Tuesday after the United States nearly doubled the estimate of its shale oil and as investors worried that central banks, following Japan's example, could begin to rein in their loose monetary policies.
Oil joined world equity markets, the dollar, bond prices and other commodities in a full-scale retreat by investors after the Bank of Japan's decision not to follow up its $1.4 trillion stimulus program announced in April.
In the U.S., the Energy Information Administration revised its estimate on domestic shale oil reserves to 58 billion barrels, up from 32 billion in 2011, as new drilling techniques unlocked deposits.
"The Bank of Japan put a little damper on the idea that stimulus measures are going to continue to drive us," said Gene McGillian, an analyst with Tradition Energy in Stamford, Connecticut.
Brent crude was off $1.47 to $102.48 a barrel by 12:00 p.m. EDT (1600) GMT, after earlier dropping over $2. U.S. oil shed 87 cents to $94.90.
McGillian noted that recent rallies towards $97 for U.S. crude have quickly subsided in the absence of clear signs that the U.S. economy is recovering.
"Some of the more nervous longs, as soon as they see momentum is slowing, look to bail from their positions," he said.
The Organization of the Petroleum Exporting Countries (OPEC) on Tuesday trimmed its forecast for 2013 world oil demand growth by 10,000 barrels per day (bpd) to 780,000 bpd.
But it expects demand to grow more quickly during the rest of the year than in the first half due to economic recovery and higher seasonal consumption, it said in a monthly report.
Increasing oil supplies and waning demand in China, the world's number two oil consumer, are likely to hold down prices.
Data from China showed a slowdown in the economy of the world's biggest energy consumer, with May exports weak and domestic activity struggling to pick up.
Implied oil demand rose in May at its lowest annual rate since September 2012, Reuters calculations show.
The 200,000 barrel per day Buzzard oilfield in Britain's North Sea was reported Monday to have returned to full production following last week's outages.
Further bearish news could surface later on Tuesday if oil stockpiles in the United States rise, as predicted.
A Reuters poll of analysts expects U.S. commercial crude oil stockpiles to have risen last week on higher imports, in a counter-seasonal increase that may weigh on prices.
(Additional reporting by Peg Mackey in London, Rebekah Kebede in Perth; Editing by Marguerita Choy)