In modern hydraulic stimulation operations, a key focus for operators and service providers is operational efficiency. While there are many factors that can affect operational efficiency, along with many ways to measure it, most agree that nonproductive time (NPT) due to equipment failure is a major barrier to efficiency gains. A key element in hydraulic stimulation is the flow path between the hydraulic pump spread and the wellbore. A failure on this path results in significant impacts to the delivery of the hydraulic stimulation service in terms of cost overruns and increased safety risks.

In recent years, specially designed valves have been incorporated into frac trees. The frac trees are typically connected to the wellhead via a flanged seal connection and to the pump spread via temporary ironwork. While the temporary ironwork is a notoriously weak link in the system, it is easily replaced when it fails, resulting in a low incidence of NPT. The frac tree itself is much more complex and it is in this area that significant NPT frequently occurs. Eliminating NPT associated with the frac tree is a complex process that is essential to efficient operations.

This paper describes the mechanisms used to evaluate wear points in the design of these systems, the methodologies used to mitigate and eliminate the causes of NPT in frac trees, and the processes used to validate the programs. Case histories are presented with a detailed examination of the issues and solutions.