What happened? Chevron releases root cause of Bishop well site incident in Weld County

WELD COUNTY, Colo. — Chevron released its findings Tuesday as to what caused the release of oil and gas from the Bishop well pad site in April.

The incident injured one person and prompted evacuations and an extensive clean-up effort in Weld County.

The report states that the April 6 incident was caused by the “improper assembly of the installation equipment for the production tree by the on-site wellhead technician contractor.”

A production tree is a group of gauges and valves used to control the flow of fluids from a production well. It’s also called a “Christmas tree.”

The production tree struck the wellhead technician as it fell to the ground, resulting in a leg fracture, the report states.

This improper assembly caused “a loss of control over the pressure within the wellbore, resulting in an uncontrolled flow — called a blowout — of fluids,” the Colorado Energy and Carbon Management Commission (ECMC) stated in April.

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Chevron said the fluid released in the incident was comprised of 80% produced water and 20% oil and gas. It was fully sealed on April 10.

The incident occurred at an oil and gas facility south of WCR 74, near the community of Galeton, and prompted the evacuation of a handful of nearby residents and the closure of Galeton Elementary School.

The exclusion zone wasn’t fully reponed for several weeks as crews cleaned structures, roads, and vehicles around the site, including Galeton Elementary School.

Chevron said it has implemented corrective measures, including pre-assembling installation equipment and revising wellhead procedures and equipment.

Additionally, the company stated that it has assisted displaced residents and continues to work with landowners on agricultural assessments.