Pipeline transportation Segment Margin increased $7.3 million, or 45%, between the third quarter periods. The contribution from our interests in the Gulf of Mexico pipelines that we acquired in 2012 and higher crude oil tariff revenues were the primary factors increasing Segment Margin. These increases were partially offset by a decrease in the contribution to Segment Margin from CHOPS as a result of ongoing improvements being made by producers at several connected production fields. Improvements at those fields were substantially completed late in the 2012 Quarter.
Our refinery services Segment Margin increased $1 million, or 6%, between the quarters due to increased NaHS sales volumes and operating efficiencies realized at several of our sour gas processing facilities as well as our favorable management of the acquisition and utilization of caustic soda in our, and our customers', operations and our logistics operations.
Supply and logistics Segment Margin increased $4.7 million, or 25%, between the quarters. The primary factors for Segment Margin increasing quarter-over-quarter were the contribution of the black oil barge transportation assets that we acquired in August 2011 and February 2012 and increased volumes handled by our expanded trucking and barge fleets. Our total volumes of crude oil and refined products increased 30% as a result of these expansions.
Other Components of Available CashCorporate general and administrative expenses included in the calculation of Available Cash before Reserves increased by $1.6 million primarily due to increased salaries and benefits associated with additional personnel to support our growth and increased equity compensation expense driven by a higher common unit price. Interest costs increased $2.2 million from the 2011 Quarter primarily as a result of increased borrowings for acquisitions and other growth projects. Capitalized interest costs of $1.3 million attributable to our growth capital expenditures and investments in the SEKCO pipeline joint venture partially offset the increase in interest expense, resulting in a net increase in interest expense of $0.9 million.