Energy experts are beginning to coalesce around the idea that oil prices will climb by the second half of 2016. Whether natural gas prices strengthen remains more questionable.

Goldman Sachs analysts led by Michael Hinds on Thursday said there are downside risks for New York Mercantile Exchange gas if, as expected, there's a mild U.S. winter on the back of a strong El Nino.

"The U.S. natural gas market's bearish sentiment has been predominantly driven by milder-than-normal weather conditions over the past few weeks, which resulted in gas demand for residential and commercial use maintaining below-seasonal levels," Hinds said.

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When combining low residential/commercial gas demand with disappointing industrial demand, "we continue to see the gas market as well oversupplied, despite lower Canadian imports relative to last year and a slowdown in natural gas production."

Gas production in the United States has resumed its downward trajectory and contracted by about 1.6 Bcf/d since early October, according to Goldman Sachs.

"Of note, the Southeast/Gulf and Northeast regions posted the steepest drop-offs, respectively accounting for 60% and 30% of the headline decline. In the Northeast, while a series of maintenance events and delays of new pipeline and expansion projects are affecting production, we nonetheless expect it to ramp-up in the near-future along with increasing offtake capacity."

The key downside risk to Goldman's $2.50/MMBtu forecast for 4Q2015 is driven by expectations for a mild winter. Next year, the slowdown in associated gas production and "strong, broad-based demand growth" should be enough of a catalyst to improve prices to $2.85/MMBtu on average with coal plant retirements, new petrochemical plants, liquefied natural gas exports and continued growth in exports to Mexico.

"However, upside risks to our Northeast production forecast and a weaker 2015 starting point imply risk to the price recovery as skewed to the downside," Hinds said.

Things may be more positive for oil prices, at least toward the back end of 2016, if Bank of England (BOE) economists are correct in their assumptions. In a report this week, BOE estimated that 60% of the recent decline in oil prices could be related to demand factors -- not excess supply. The analysis is based on the movement of oil prices parallel to other commodities. If oil prices fall simultaneously with other commodities, there must be a common cause because the supply of several commodities would not balloon at the same time, the economists said.

BOE's model suggests that oil supply and demand simultaneously were impacting oil prices in similar magnitudes. China's economy -- and its industrial demand -- were faltering as the global oil surge began pressuring prices. Economists said it was unlikely that two events would occur at nearly the same time independently of each other.

U.S. oil production now is falling, while China's economy appears to be adjusting, with a record trade surplus in September, BOE said. By the middle of 2016, if China is back on track demand-wise, BOE's model suggests that oil demand weakness would ease and with it, oil prices could rally by as much as $35/bbl.

And BOE's team isn't the only group pointing to higher oil prices in 2016.

Tudor, Pickering, Holt & Co. Managing Director Dave Pursell said in a webcast earlier this month that the global crude oil markets are almost balanced after a period of supply swamping demand. Inventory data suggest that the market is tighter than current conventional consensus, according to Pursell. As a result, he said the price of oil could hit as much as $80.00/bbl next year.

Evercore ISI analyst Doug Terreson also sees oil prices rising toward the last half of the year.

"We think production will flatten out in 2016," Terreson said in a webcast earlier this month. Based on forecasts for 2016 OPEC and non-OPEC supply, "when you do the math, you conclude that inventory should decline next year." That would mean that oil prices would begin gravitating upward toward the end of the year.

But it could take longer for the markets to balance, according to Rob Kaplan, incoming CEO of the Federal Reserve Bank of Dallas. Kaplan, who took over the Dallas office in September, spoke at the University of Houston on Wednesday.

"It is our view that it will not be until late 2016 or early 2017 before inventories stabilize and daily production and consumption reach some reasonable degree of balance," Kaplan said. "Only after that point should demand be sufficient to begin working down this high level of inventory."

While supplies are falling in the United States, other factors have to balance out as well. "These include the level of demand in China as well as consumer demand in the U.S., and additional production coming online in Iran and Libya," Kaplan said. "Of course, geopolitical developments in the Middle East could impact production levels as well."

Like their gas price forecast, Goldman analysts are less enthusiastic about the outlook for oil.

"Mild winter weather over the coming months (a concerning risk given current El Nino conditions) could see weak heating demand in the U.S. and Europe," Hind and his colleagues said. "If this materializes, it would likely be the trigger for adjustments through the physical market, pushing oil prices down to cash costs which we estimate are likely around $20/bbl. As such a drop in spot prices to cash costs would force rapid adjustments, it would likely be followed by periods of stronger returns in both spot and roll returns, as historically has been the case (1986, 1988 and 1998)."

Goldman is maintaining its 2016 oil price forecast for $45/bbl West Texas Intermediate with Brent at $50/bbl.