Valve Automation Solutions(5)

SAFETY FOR FLOW LINE VALVES—API 6D

Figure 3. 6D application on a flow line equipped for ESD/PSDBeyond API 6A use at the Christmas tree and the production choke valve, valves in a shale application generally are part of the gathering, processing and storage systems. The API 6D, Specification for Pipeline Valves, and many other standards such as API 598, 599, 600, 602 and ASME B16.34 apply. The quarter-turn ball valve is often found in the ESD/PSD applications as well as check, gate, plug and butterfly valves (Figure 3).

Gathering lines carry the hydrocarbons from the well to the various separation and treating facilities, then flow to intermediate storage and fiscal custody transfer stations before product is transmitted via pipeline further downstream to processing and distribution points. At all points along the way, flow lines are susceptible to rupture, overpressure, backflow or hazards that would require immediate shutdown.

Flow lines also travel to and from facilities over considerable distances, crossing rivers, interstates and highways, areas with much human activity and to locations in remote areas where there is limited infrastructure and local supervision. These flow lines need shut-in capabilities. Automated ESD/PSD valves are viable solutions to address the many potential problems that can result.

API 6A AND/OR 6D

Figure 4. Pneumatic scotch-yoke fail close actuatorGenerally, the same technologies used near the well are available for API 6D applications. In fact, other than special valve considerations and probable power supply source availability issues, there really is very little difference in the basic automation functionality between 6A and 6D applications. The few differences—available power source, experience with the application and the total cost of ownership—can make some solutions more prevalent for certain applications (Figure 4).

CONCLUSION

Shale plays continue to be discussed as a catalyst for the United States’ effort to become energy self-sufficient. Because oil and natural gas holds the most potential for reaching that independence, the need to produce from domestic shale sources has meant a dramatic increase in the number of wells drilled and produced. With the energy industry spearheading positive safety solutions through technology, ESD and PSD valves and actuators will play a prominent role in increasing the public’s confidence in the industry’s initiatives toward safety and environmental preservation.

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