an increase of $16 million in operating expenses primarily due to a $7 million increase resulting from a change in the classification of certain customer reimbursements previously recorded as a reduction to operating expenses that are now classified as revenue following the adoption of ASC 606 on January 1, 2018, a $4 million increase in utilities and ad valorem taxes on the fractionators, and a $3 million increase in overhead costs; and
a decrease of $5 million in storage margin primarily due to the expiration and amendments to various NGL and refined products storage contracts.
Crude Oil Transportation and Services
Three Months Ended
Crude transportation volumes (MBbls/d)
Crude terminals volumes (MBbls/d)
Cost of products sold
Unrealized (gains) losses on commodity risk management activities
Operating expenses, excluding non-cash compensation expense
Selling, general and administrative expenses, excluding non-cash compensation expense
Adjusted EBITDA related to unconsolidated affiliates
Segment Adjusted EBITDA
Crude transportation volumes increased due to placing the Bakken pipeline in service in June 2017 as well as increased volumes on existing pipelines due to increased production in West Texas. Crude terminal volumes increased due to increased volumes delivered to our Nederland crude terminal from the Bakken pipeline and from increased West Texas production.
Segment Adjusted EBITDA. For the three months ended June 30, 2018 compared to the same period last year, Segment Adjusted EBITDA related to our crude oil transportation and services segment increased due to the net impacts of the following:
an increase of $332 million in segment margin (excluding unrealized losses on commodity risk management activities) due to a $193 million increase resulting primarily from placing our Bakken pipeline in service in the second quarter of 2017 as well as a $27 million increase resulting from increased throughput, primarily from Permian producers, on existing pipeline assets; a $100 million increase (excluding a net change of $264 million in unrealized gains and losses) from our crude oil acquisition and marketing business primarily resulting from more favorable market price differentials between the West Texas and Gulf Coast markets; and a $9 million increase in terminal fees primarily from ship loading fees at our Nederland facility as a result of increased exports;
a decrease of $12 million in selling, general and administrative expenses primarily due to higher professional fees recorded in the prior period; and
an increase of $6 million in Adjusted EBITDA related to unconsolidated affiliates due to a new contract at one of our joint ventures; partially offset by
an increase of $30 million in operating expenses due to a $13 million increase primarily resulting from placing our Bakken pipeline in service in the second quarter of 2017; a $3 million increase resulting from the addition of certain joint venture transportation assets in the second quarter of 2017; and a $14 million increase from existing transportation assets due to increases of $7 million in utilities, $5 million in expense projects, $5 million in ad valorem taxes and $5 million in management fees, partially offset by decreases in environmental fees of $5 million and capacity leases of $3 million.