Revenues and Other
Oil, natural gas and NGL sales increased in 2017, including the successor and predecessor periods, by $40 million, or 10%, when compared to the year ended December 31, 2016 due to an increase in realized oil and NGL prices and an increased mix of oil production compared to gas production as a result of the Hill Acquisition and Hugoton Disposition, partially offset by decreased natural gas and NGL production.
Electricity sales increased in 2017, including the successor and predecessor periods, by $2 million, or 10%, when compared to the year ended December 31, 2016 primarily due to higher volumes sold externally because of lower internal usage related to lower steamflood production activity, as well as higher prices.
Losses on oil and natural gas derivatives increased in 2017, including the successor and predecessor periods, by $38 million, or 242%, when compared to the year ended December 31, 2016 primarily due to increased hedging activity, a portion of which was required by the RBL Facility, and improved commodity prices relative to the fixed prices of our derivative contracts.
Marketing revenues in 2017, including the successor and predecessor periods, were comparable to the year ended December 31, 2016.
Other revenues decreased in 2017, including the successor and predecessor periods, by $2 million, or 29%, when compared to the year ended December 31, 2016 due to a decrease in helium gas sales as a result of the Hugoton Disposition.
Expenses
Lease operating expenses include fuel, labor, field office, vehicle, supervision, maintenance, tools and supplies, and workover expenses. Lease operating expenses decreased in 2017, including the successor and predecessor periods, by $7 million, or 4%, when compared to the year ended December 31, 2016 primarily due to the effect of the Hugoton Disposition (natural gas production) and the Hill Acquisition (oil production), reflecting higher operating expenses associated with natural gas production compared to oil production, and our production decline as a result of decreased development activity and a reduction of steamflooding. While production volumes decreased as a result of the Hugoton Disposition and Hill Acquisition, which decrease adversely impacted costs per Boe, our oil, natural gas and NGL revenues remained constant due to a product mix more heavily weighted towards oil.
Electricity generation expenses increased in 2017, including the successor and predecessor periods, by $1 million, or 6%, when compared to the year ended December 31, 2016, primarily due to the increase in the price of natural gas used in steam generation, for which electricity generation is aby-product.
Transportation expenses decreased in 2017, including the successor and predecessor periods, by $16 million, or 39%, when compared to the year ended December 31, 2016, primarily due to the cancellation of uneconomic contracts in the Chapter 11 Proceedings and the Hugoton Disposition, which required significant transportation expenses.
Marketing expenses in 2017, including the successor and predecessor periods, were comparable to the year ended December 31, 2016.
General and administrative expenses decreased in 2017, including the successor and predecessor periods, by $15 million, or 19%, when compared to the year ended December 31, 2016 primarily due to the management change in conjunction with our emergence from bankruptcy. The reduction in absolute dollars offset by lower production resulted in higher general and administrative expenses per Boe for the year ended December 31, 2017 when compared to the same period in 2016. General and administrative expenses includenon-recurring
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