The hypothetical NGL barrel jumped to its highest level in more than five months at both the Mont Belvieu, Texas, and Conway, Kan., hubs in the past week as margins expanded in double figures for all components but one.

Ethane at Mont Belvieu pushed toward 26 cents per gallon (gal) as it reached its highest level since the first week of the year. At Conway, the average price over the last week surpassed 22 cents/gal for the first time since early February.

U.S. crude oil inventories have declined by almost 10% since the start of the second quarter, which is the steepest drop in that time frame in the past 20 years, En*Vantage said in a recent report. The Cushing, Okla., hub’s stocks are more than 14% below its level at the same point in 2016 and En*Vantage expects the U.S. crude inventory to slide by another 14 million barrels over the next four weeks.

The analysts attribute oil’s recent strength to export cuts by Saudi Arabia and the assumption that Libya and Nigeria are nearing or have hit their production ceilings. Venezuela remains difficult to gauge following the recent vote to rewrite the country’s constitution and the threat of sanctions by the U.S. government.

While the average weekly price of ethane is up 39.1% at Mont Belvieu over the price of a year ago, and 57.1% higher at Conway, its rise at both hubs since the start of the second quarter has been more modest—9.8% at Mont Belvieu and 16.7% at Conway. Prices are constrained at the high end by record-high inventories and supported at the low end by strong cracking and export demand, En*Vantage explained.

Propane rose 9.8% in the last week at both hubs and its Mont Belvieu price is 72% above what it was last year at this time. U.S. propane stocks are tight and it is selling at a 60% ratio to West Texas Intermediate crude oil, compared to a 44% relationship last year at this time. At Conway, the increase over 12 months ago is a whopping 90.3%.

The butanes continued their rallies at both hubs, with Mont Belvieu’s butane price cracking 80 cents/gal for the first time since April and hitting its highest point since late February. Conway butane also surpassed 80 cents/gal for the first time since late February and the 12-month increases were 55.9% at Mont Belvieu and 57.9% at Conway.

Storage of natural gas in the Lower 48 increased by 20 billion cubic feet (Bcf) in the week ended July 28, the U.S. Energy Information Administration reported. The increase, which matched the Bloomberg consensus, is well below the five-year average of 44 Bcf. A year ago, storage decreased by 3 Bcf. The increase resulted in a total of 3.01 Tcf. The figure is 8.5% below the 3.289 Tcf figure at the same time in 2016 and 3% above the five-year average of 2.923 Tcf.

Joseph Markman can be reached at and @JHMarkman.