The sharp drop in U.S. oil rig counts has helped lift crude prices off their lows, but it won't slow production or alleviate oversupply, Goldman Sachs said.
"The decline in the U.S. rig count likely remains well short of the level required to slow U.S. shale oil production to levels consistent with a balanced global market," Goldman said in a note Tuesday. "Lower oil prices will be required over the coming quarters to see the U.S. production growth slowdown materialize."
It estimates the current rig count will bring production growth from the Big-three shale basins -- Permian, Eagle Ford and Bakken -- to 615,000 barrels a day in the fourth quarter of this year, while continued productivity growth may push that as high as 690,000 barrels a day.
Which, not how many
It's about which rigs are getting cut. U.S. crude production was estimated at around 8.6 million barrels a day in 2014, according to data from the International Energy Agency.
"High-grading," with producers eliminating the least efficient rigs first, will also keep production humming along, it said, estimating the Big-three plays would need to cut their horizontal rig count by another 30 percent to 407 by the fourth quarter to bring production growth to 400,000 barrels a day by then.
Additionally, the rig-count drop may be concentrated in non-contracted rigs, Goldman noted. That's a cost-cutting play, as it can allow producers to negotiate lower rates, it said.
"While this focus on cost reduction initially leads to a sharp drop in the rig count, it provides little information on the future path of the rig count and companies' aim at high-grading," it said. Once price negotiations are done, those rigs could quickly come back on line, it said.
Productivity gains are another likely wildcard suggesting the rig-count decline won't dampen supply much, Goldman said.
"The impact of productivity gains is likely to be most visible over a longer period of time as it compounds on itself," Goldman said, with the possibility it's more likely to be felt in 2016 than this year.
In January, Goldman cut its oil price forecasts sharply.
On a three-, six- and 12-month basis, Goldman forecasts Brent at $42, $43 and $70 a barrel, respectively, with WTI at $41, $39 and $65 a barrel.
In Asian trade Wednesday, Brent for March delivery was around $56.30 a barrel, off the low of around $46.40 touched mid-January, while WTI for March delivery was trading around $50.33 a barrel after touching lows of around $43.58 in late January.
"It is premature to translate the recent collapse in the oil rig count into an immediate reduction in output, a tightening in market balances and therefore a bottom in prices," JPMorgan said in a note Wednesday. "Only if there is no offsetting increase in average well productivity – which seems unrealistic – does the drop in rigs imply falling production from mid second quarter of 2015."
JPMorgan estimates that a rise of 15 percent in average initial production rates over the first half, even if the rig count is cut in half, still implies average output growth of more than 215,000 barrels a day for the full year.
JPMorgan expects the recent rally in oil is just position driven and is likely to be reversed over the next few weeks, with CFTC data indicating non-commercial short positions in WTI futures at end-January were at their highest level since 2010.
It expects oil prices will trough in March or April, with Brent futures to hit a low point at around $38 a barrel, with a shallow lower-case-U-shaped recovery to around $58 in the fourth quarter.
Of course, these forecasts aren't as bearish as Citigroup's, which are for WTI to potentially fall as low as $20 a barrel.
"Not only is the market oversupplied, but the consequent inventory build looks likely to continue toward storage tank tops," Citigroup said in a note Monday. Citigroup expects shale producers may cut rig counts by around 50 percent, which combined with some marginal well shutdowns would lower U.S. production growth to around 600,000 barrels a day this year.
—By CNBC.Com's Leslie Shaffer; Follow her on Twitter