New EPA regulations can add ‘green’ to the bottom line

The scene on flowback locations is changing rapidly as gas flaring becomes an extinct practice. With new US Environmental Protection Agency (EPA) regulations beginning to take effect and the deadline for compliance with Quad O regulations rapidly approaching, many operators are ahead of these regulations while others are just beginning the educational process to decipher these drastic new practices. Many will find this to be a seamlessly integrated and profitable new endeavor, and others will struggle to grasp an understanding of exactly what these new changes will entail.

New Quad O regulations

FIGURE 1. Fluid from the multiple wells on this Colorado well site flows through the low-pressure separator located in the red building and into flowback fluid recovery tanks (not shown). (Images courtesy of Compressco Partners)

What is the purpose of Quad O? Technically, it is the Standards of Performance for Crude Oil and Natural Gas Production, Transmission, and Distribution. These regulations establish emission standards and compliance schedules for the control of volatile organic compounds and sulfur dioxide emissions from affected facilities that commence construction, modification, or reconstruction after Aug. 23, 2011.

Practically speaking, these regulations affect certain oil and natural gas well locations. In addition, these regulations impact equipment used at oil and gas facilities, such as centrifugal and reciprocating compressors, by limiting the amount of vapors that can be emitted into the atmosphere. Also included in the regulations are certain pneumatic controllers and storage vessels.

These new, stricter EPA regulations regarding vapor recovery are quickly approaching, and operators are scrambling to find solutions to capture or eliminate these vapors during flowback and everyday operations of their facilities. Two upcoming dates will trigger significant changes. As of Oct. 15, 2013, the regulations will require storage tanks emitting more than 6 tons per year of volatile organic compounds to capture vapors. New regulations concerning the use of pneumatic controllers at wellheads also will be triggered. Regulations for “green completions” will be added to the required environmental compliance list concerning vapors emitted during flowback on Jan. 1, 2015.

Going green

Green completions take place during the cleanup stage of the completion after a well has been hydraulically fractured. The cleanup involves removing the water from the wellbore that was necessary to fracture the well. During this flowback, natural gas is produced with the water as it is extracted from the well.

What makes the well completion environmentally friendly is the gas being separated from the water and placed in a pipeline instead of being released to the atmosphere or flared like traditional flowback applications of the past. Green completion increases profits by using portable compression equipment to capture the gas and condensate while the recovered gas is directed to a pipeline and sold.

FIGURE 2. The compressor unit on this Colorado well site is configured to pull high-Btu vapors from the low-pressure separator.

The use of compression for vapor recovery has been proven effective for many years. Compressco Partners entered the vapor recovery unit market with the GasJack compressor seven years ago. The design can provide flexibility from a compression ratio standpoint in addition to the large suction/discharge operating parameters that can be achieved.

During vapor recovery applications – particularly flow-back – maintaining the correct controls and configurations can be challenging since conditions are constantly changing. To address these problems, the company modified the controls of its 46-hp compressor to accommodate varying vapor volumes.

Vapor volume instability often can occur during flowback due to fluctuations in fluid flow and early production inconsistencies. The eight-cylinder integral engine/compressor can accommodate these fluctuations when combined with specialized controls and regulators.

How it works

The two blue and white tanks in Figure 1 are high-pressure tanks that the wells flow back into. Gas and flow-back fluid are separated, with high-pressure gas going to sales and fluid dumped to a low-pressure separator (housed in the red building in the picture). The compressor unit (Figure 2) is configured to pull high-Btu vapors from the low-pressure separator. The low-pressure separator then dumps liquid to the flowback fluid recovery tanks.

The pressure drop from the high-pressure vessels to the low-pressure separator creates additional flash gas, which is compressed back up to line pressure. The back-pressure valve is necessary to maintain enough pressure to operate all the control valves within the low-pressure separator and to dump the fluid to the recovery tanks.

Each location parameter varies, but this location used 35 psig as a starting point. The pressure may be raised or lowered during operation to optimize flash gas production. Using the clean dry gas from the high-pressure separators can result in the unit running continuously and more consistently.

Field results

By working directly with operators and partnering with flowback companies such as Tetra Technologies, Compressco Partners provides compression to manage the regulatory restrictions for vapor recovery while making it an extremely profitable process.

Marcellus and Utica flowback locations are becoming more profitable with these flaring alternatives. For example, a well operator in Washington County, Pa., uses dual GasJack compressors to recover vapors during flowback operations.

One compressor takes suction directly from the low-stage separator at approximately 30 psig and sends the nearly 1,800-Btu gas down the sales line to make the location more profitable. A second compressor, using specialized controls, maintains a steady 6 to 10 oz. of positive pressure on the storage tanks while using a blanket gas system to ensure reliability and consistent run time. This example is just one of many from a variety of applications where vapors can be recovered during flow-back operations.

In another example, some operators in the Utica shale have calculated a combination of savings and production uplift between US $80,000 and $90,000 during flow-back on a four-well pad.

By eliminating the need for two vapor destruction units at approximately $8,000 per unit and then calculating the profit increase from the sale of vapors, the value in capturing those vapors to the bottom line is quickly realized. By converting approximately 13 MMcf of vapors during flowback from the four wells into the sales line and selling for more than $6/Mcf (due to the high-Btu gas), a “green completion” added more “green” to the bottom line.