The midstream natural gas industry is the link between the exploration and production of natural gas and the delivery of its components to end-use markets.

Our natural gas midstream segment is engaged in providing natural gas processing, gathering and other related services. As of December 31, 2011, we owned and operated natural gas midstream assets located in Oklahoma, Texas and Pennsylvania, including six natural gas processing facilities having 420 MMcfd of total capacity and approximately 4,426 miles of natural gas gathering pipelines.

How Our Midstream Business Works
Our natural gas midstream business generates revenues primarily from gas purchase and processing contracts with natural gas producers and from fees charged for gathering natural gas volumes and providing other related services. During the year ended December 31, 2011, our natural gas midstream business generated a majority of its gross margin from two types of contractual arrangements under which its margin is exposed to increases and decreases in the price of natural gas and NGLs: (i) gas purchase/keep-whole and (ii) percentage-of-proceeds. For the fourth quarter of 2011, approximately 12% of our system throughput volumes were gathered or processed under gas purchase/keep-whole contracts, 55% were gathered or processed under percentage-of-proceeds contracts and 33% were gathered or processed under fee-based gathering contracts. A majority of the gas purchase/keep-whole and percentage-of-proceeds contracts include fee-based components such as gathering and compression charges.
In 2011, 47% of our natural gas midstream segment revenues and 40% of our total consolidated revenues resulted from four of our natural gas midstream customers, Conoco Phillips Company, Williams NGL Marketing, LLC, Tenaska Marketing Ventures, and Targa Liquids Marketing and Trade.
Gas Purchase/Keep-Whole Arrangements. Under gas purchase/keep-whole arrangements, we generally buy natural gas from producers based upon an index price and then sell the NGLs and the remaining residue gas to third parties at market prices. Because the extraction of the NGLs from the natural gas during processing reduces the volume of natural gas available for sale, profitability is dependent on the value of those NGLs being higher than the value of the volume of gas reduction or “shrink.” Under these arrangements, revenues and gross margins decrease when the price of natural gas increases relative to the price of NGLs. Accordingly, a change in the relationship between the price of natural gas and the price of NGLs could have a material adverse effect on our business, results of operations or financial condition.
Percentage-of-Proceeds Arrangements. Under percentage-of-proceeds arrangements, we generally gather and process natural gas on behalf of producers, sell the resulting residue gas and NGL volumes at market prices and remit to producers an agreed-upon percentage of the proceeds of those sales based on either an index price or the price actually received for the gas and NGLs. Under these types of arrangements, our revenues and gross margins increase as natural gas prices and NGL prices increase, and our revenues and gross margins decrease as natural gas prices and NGL prices decrease.
Fee-Based Arrangements. Under fee-based arrangements, we receive fees for gathering, compressing and/or processing natural gas. The revenues we earn from these arrangements are directly dependent on the volume of natural gas that flows through our systems and are independent of commodity prices. To the extent a sustained decline in commodity prices results in a reduction in drilling and development of a new supply in the areas we serve, our revenues from these arrangements would be reduced.
In many cases, we provide services under contracts that contain a combination of more than one of the arrangements described above. The terms of our contracts vary based on gas quality conditions, the competitive environment at the time the contracts were signed and customer requirements. The contract mix and, accordingly, exposure to natural gas and NGL prices, may change as a result of changes in producer preferences, expansion in regions where some types of contracts are more common and other market factors.
Natural Gas Marketing Contracts. We are also engaged in natural gas marketing by aggregating third-party volumes and selling those volumes into interstate and intrastate pipeline systems such as Enogex and Panhandle Eastern Pipeline and at market hubs accessed by various interstate pipelines. Revenues from this business do not generate qualifying income for a publicly traded limited partnership, but we do not expect it to have an impact on our tax status, as it does not represent a significant percentage of our operating income. For the three years ended December 31, 2011, natural gas marketing activities generated $2.6 million, $2.8 million and $1.8 million in net revenues.
Commodity Derivative Contracts. We utilize derivative contracts to hedge against the variability in our frac spread. Our frac spread is the spread between the purchase price for the natural gas we purchase from producers and the sale price for NGLs that we sell after processing. We hedge against the variability in our frac spread by entering into costless collar and swap derivative contracts to sell NGLs forward at a predetermined commodity price and to purchase an equivalent volume of natural gas forward on an MMBtu basis. While the use of derivative instruments limits the risk of adverse price movements, such use may also limit future revenues or cost savings from favorable price movements.
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System Volumes

Commodity Hedging:
We utilize collar derivative contracts to hedge against the variability in our frac spread. Our frac spread is the spread between the purchase price for the natural gas we purchase from producers and the sale price for NGLs that we sell after processing. We hedge against the variability in our frac spread by entering into costless collar and swap derivative contracts to sell NGLs forward at a predetermined commodity price and to purchase an equivalent volume of natural gas forward on an MMBtu basis. While the use of derivative instruments limits the risk of adverse price movements, such use may also limit future revenues or cost savings from favorable price movements.
Major Midstream Systems
Panhandle
The Panhandle System is a natural gas gathering system stretching over eleven counties in the Anadarko Basin of the panhandle of Texas and Oklahoma. The system consists of approximately 1,817 miles of natural gas gathering pipelines, ranging in size from two to 16 inches in diameter, and the Beaver, Spearman and Sweetwater natural gas processing plants. Included in the system is an 11-mile, 10-inch diameter, FERC-jurisdictional residue line.
The Panhandle System is comprised of a number of major gathering systems and 43 related compressor stations that gather natural gas, directly or indirectly, to the Antelope Hills, Beaver, Spearman and Sweetwater plants. These include the Beaver, Perryton, Spearman, Wolf Creek/Kiowa Creek and Ellis systems.
These gathering systems are located in Beaver, Ellis, Harper and Roger Mills Counties in Oklahoma and Hansford, Hemphill, Hutchinson, Lipscomb, Ochiltree, Roberts and Wheeler Counties in Texas. The Beaver plant has 100 MMcfd of inlet gas capacity. The plant is capable of operating in high ethane recovery mode or in ethane rejection mode and has instrumentation allowing for unattended operation of up to 16 hours per day. The Spearman plant has 100 MMcfd of inlet capacity. The plant is capable of operating in high ethane recovery mode or in ethane rejection mode and has instrumentation allowing for unattended operation of up to 16 hours per day. The Sweetwater plant is capable of operating in high ethane recovery mode or in ethane rejection mode and has instrumentation allowing for unattended operation of up to 16 hours per day.
Crossroads
The Crossroads System is a natural gas gathering system located in the southeast portion of Harrison County, Texas. The Crossroads System consists of approximately eight miles of natural gas gathering pipelines, ranging in size from eight to twelve inches in diameter, and the Crossroads plant. The Crossroads System also includes approximately 20 miles of six-inch NGL pipeline that transport the NGLs produced at the Crossroads plant to the Panola Pipeline.
The Crossroads plant has 80 MMcfd of inlet capacity. The plant is capable of operating in high ethane recovery mode or in ethane rejection mode and has instrumentation allowing for unattended operation of up to 16 hours per day.
Crescent
The Crescent System is a natural gas gathering system stretching over seven counties within central Oklahoma's Sooner Trend. The system consists of approximately 1,708 miles of natural gas gathering pipelines, ranging in size from two to 10 inches in diameter, and the Crescent natural gas processing plant located in Logan County, Oklahoma. Fourteen compressor stations are operating across the Crescent System.
The Crescent plant is a NGL recovery plant with current capacity of approximately 40 MMcfd. The Crescent facility also includes a gas engine-driven generator which is routinely operated, making the plant self-sufficient with respect to electric power.
Arkoma
The Arkoma System is a natural gas gathering system in eastern Oklahoma. The system consists of approximately 78 miles of natural gas gathering pipelines.
North Texas Gas Gathering
The North Texas assets are located in the southern portion of the Fort Worth Basin of North Texas and include approximately 136 miles of gas gathering pipelines and approximately 240,000 acres dedicated by active producers. This expands the geographic scope of the natural gas midstream segment into the Barnett Shale play in the Fort Worth Basin.
Hamlin
The Hamlin System is a natural gas gathering system stretching over eight counties in West Central Texas. The system consists of approximately 517 miles of natural gas gathering pipelines, ranging in size from two to 12 inches in diameter and with current capacity of approximately 20 MMcfd, and the Hamlin natural gas processing plant located in Fisher County, Texas. Eight compressor stations are operating across the system.
Marcellus System
During 2010, we began construction of gathering systems in Wyoming and Lycoming Counties in Pennsylvania. We have completed initial construction of 12-inch gas gathering pipelines in Wyoming County and began gathering natural gas on the system in June 2010. In February 2011, we commenced operations on the first phase of the Lycoming County system. In April 2011, we also began construction on the second phase of the Lycoming County system, which is expected to be operational in the first quarter of 2012. The Lycoming County system consists of a 30- inch trunk line. Construction and development to provide gathering, compression and related services in Lycoming and Wyoming Counties are ongoing. The gathering infrastructure captures current and expected volumes in the Marcellus Shale area. The Marcellus System delivers the natural gas to local customers and provides avenues for local producers to major pipeline systems such as Transco. We are also a partner in a joint venture that transports and supplies fresh water to natural gas producers drilling in the Marcellus Shale in Pennsylvania. The water pipeline is expected to be operational in 2012.