Revenue during the quarter surged 54.97 percent to $2,749.07 million from $1,773.94 million in the previous year period. Gross margin for the quarter contracted 1058 basis points over the previous year period to 22.02 percent. Total expenses were 88.20 percent of quarterly revenues, up from 82.06 percent for the same period last year. That has resulted in a contraction of 614 basis points in operating margin to 11.80 percent.

Operating income for the quarter was $324.42 million, compared with $318.24 million in the previous year period.

However, the adjusted EBITDA for the quarter stood at $464.15 million compared with $444.59 million in the prior year period. At the same time, adjusted EBITDA margin contracted 818 basis points in the quarter to 16.88 percent from 25.06 percent in the last year period.

"All three of our business segments reported higher first-quarter adjusted EBITDA compared with the same period last year, driven by increased fee-based services across the partnership's footprint," said Terry K. Spencer, president and chief executive officer of ONEOK and ONEOK Partners. "Our performance through the first three months of 2017 and the increased drilling rig activity in the basins we serve has us well-positioned for the remainder of 2017. Severe winter weather in January impacted first-quarter 2017 volumes, primarily in the Williston Basin, but was taken into consideration when setting 2017 expectations. Since January, volumes have recovered and are now averaging above November 2016 levels."

Oneok Partners Lp has generated cash of $280.31 million from operating activities during the quarter, up 5.28 percent or $14.05 million, when compared with the last year period.

The company has spent $109.44 million cash to meet investing activities during the quarter as against cash outgo of $169.49 million in the last year period. It has incurred net capital expenditure of $112.42 million on net basis during the quarter, down 37.92 percent or $68.68 million from year ago period.

The company has spent $162.79 million cash to carry out financing activities during the quarter as against cash outgo of $91.96 million in the last year period.

Cash and cash equivalents stood at $8.48 million as on Mar. 31, 2017, down 14.23 percent or $1.41 million from $9.88 million on Mar. 31, 2016.

Working capital remains negative

Working capital of Oneok Partners Lp was negative $1,628.79 million on Mar. 31, 2017 compared with negative $852.83 million on Mar. 31, 2016. Current ratio was at 0.40 as on Mar. 31, 2017, down from 0.50 on Mar. 31, 2016.

Days sales outstanding went down to 12 days for the quarter compared with 13 days for the same period last year.

Days inventory outstanding was almost stable at 6 days for the quarter, when compared with the last year period. At the same time, days payable outstanding went down to 15 days for the quarter from 20 for the same period last year.