On January 29, 2020, the Daniel H. Wendland 1-H well (Wendland 1-H well) in Burleson County, Texas, experienced a blowout resulting in a fire that fatally injured three contract workers and seriously injured another. The well was being operated by Chesapeake Operating, L.L.C. (Chesapeake) at the time of the incident. The U.S. Chemical Safety and Hazard Investigation Board (CSB) investigated the incident and identified several safety issues that contributed to the blowout and fire.
Table of Contents
Background
- The Wendland 1-H well is located in a rural area approximately 91 miles northwest of Houston.
- At the time of the incident, the well was in an underpressured state, meaning that the pressure of the fluids within the reservoir was lower than the pressure of a column of water at the same depth.
- Because of the low reservoir pressure, the well required artificial lift to bring the oil to the surface.
Well workovers are routine maintenance procedures performed on oil and gas wells. Workovers may involve repairs or other actions designed to maintain or increase production. Well control is an essential safety aspect of workovers and other well operations. Well control refers to the methods used to prevent the uncontrolled flow of fluids (a blowout) from a well.
The Incident
The workover that culminated in the blowout and fire began on January 27, 2020. The initial scope of the workover was to repair a suspected leak in the well’s tubing. The blowout occurred around 3:00 p.m. on January 29, 2020, as workers were replacing the tubing head on the well.
Here’s a timeline of the key events leading up to the blowout:
- January 27, 2020: Workers began preparing the well for the workover operation. This involved pumping fluids (treated water and hot water) into the well. The purpose of these actions was to confirm the leak and to remove paraffin wax from the well’s components.
- January 28, 2020: The work crew removed the rod string and tubing from the well.
- January 29, 2020: Work began to replace the well’s tubing head. To prepare for the work, workers pumped 50 barrels of brine into the well to create hydrostatic pressure against the formation.
Workers observed some gas release after this, which was not unusual. However, the well was not properly monitored, and the brine that was intended to act as a hydrostatic barrier was gradually lost to the formation. The loss of the brine led to a decrease in pressure within the wellbore, which allowed oil and gas from the formation to flow into the well. The influx of oil and gas resulted in a blowout. The hydrocarbons released from the well ignited shortly after the blowout began, engulfing the surrounding area in flames.
Safety Issues
The CSB’s investigation identified four key safety issues that contributed to the incident:
- Well Planning
- Well Control for Completed Wells in Underpressured Reservoirs
- Ignition Source Management
- Federal Regulatory Safety Requirements
1. Well Planning
The CSB found that Chesapeake did not adequately plan for the workover, particularly well control during the operation. Industry guidance from the American Petroleum Institute (API) recommends a well planning process that includes:
- Gathering information about the well
- Analyzing that information to identify potential hazards
- Creating plans and procedures to address those hazards
Chesapeake’s planning process was deficient in two key areas:
- Well History Review: Chesapeake and its contractors did not adequately review the Wendland 1-H well’s history, which included 22 documented well control events during 34 workovers since 1993. This history showed that the well had experienced well control issues in the past and was capable of flowing unexpectedly. Had Chesapeake reviewed this history, they and their contractors would have been aware of the well’s potential to flow, which may have resulted in different well control choices.
- Written Procedures: Chesapeake did not have written well control procedures for the tubing head replacement task. The absence of procedures contributed to inconsistent and ineffective well control practices.
2. Well Control for Completed Wells in Underpressured Reservoirs
The sources highlight the challenge of maintaining well control in completed wells in underpressured reservoirs, such as the Wendland 1-H well. Completed wells have an open path to the reservoir. This open path, combined with the low reservoir pressure, makes it challenging to maintain a hydrostatic barrier, which is typically achieved by ensuring the pressure of the fluid column in the well is higher than the pressure of the formation.
Chesapeake’s approach to well control was inadequate:
- Ineffective Hydrostatic Barrier: Workers attempted to establish a hydrostatic barrier by pumping 50 barrels of brine into the well. However, they did not account for the rate at which this brine would be lost to the formation. The brine was essentially a temporary measure, and the well was not overbalanced for the duration of the workover.
- Ineffective Secondary Barrier: Chesapeake relied on open surface valves and a stabbing valve as secondary barriers. However, open surface valves are mitigative controls, meaning they are only activated after a release has begun. Relying on open surface valves, and a stabbing valve, increased the risk to workers because it required them to be close to the wellhead to close the valve in the event of a blowout. Additionally, the tubing head was not fully bolted in place and did not function as a barrier.
3. Ignition Source Management
The sources stress the importance of managing potential ignition sources in well workover operations, which inherently involve flammable materials. Chesapeake did not adequately assess or mitigate potential ignition sources at the well site.
- Potential Ignition Sources: There were multiple potential ignition sources near the wellhead, including vehicles, a diesel generator, power tools, and electrical equipment.
- Insufficient Risk Assessment: Although Chesapeake had a Contractor Health, Safety, Environmental, and Regulatory Handbook that addressed some ignition source controls, they did not adequately assess the risks posed by potential ignition sources at the well site. Additionally, workers were using a power pack that they believed was intrinsically safe when it was not.
The presence of multiple ignition sources near the wellhead, combined with the lack of a thorough risk assessment, increased the likelihood that a hydrocarbon release would ignite.
4. Federal Regulatory Safety Requirements
The CSB concluded that the lack of federal regulations specific to onshore oil and gas well drilling, servicing, production, and workover operations contributed to the incident.
OSHA Exemptions: OSHA historically exempted oil and gas well drilling and servicing operations from its Control of Hazardous Energy (lockout/tagout) standard and its Process Safety Management (PSM) standard. These exemptions persist despite OSHA’s recognition of the hazards inherent in the oil and gas industry.
- Control of Hazardous Energy: The CSB determined that well control principles are analogous to controlling hazardous energy and that applying OSHA’s Control of Hazardous Energy standard to oil and gas operations would improve well control practices.
- Process Safety Management: Applying elements of OSHA’s PSM standard, such as Process Safety Information, Process Hazard Analysis, and Operating Procedures, to oil and gas workover operations would likely enhance safety by requiring operators to formally identify and address hazards.
The CSB’s findings highlight the need for comprehensive federal safety regulations specific to onshore oil and gas well operations.
Conclusions
The CSB determined that the primary cause of the Wendland 1-H well blowout was a lack of well planning, particularly regarding well control procedures. This lack of planning, combined with insufficient industry guidance on well control for completed wells in underpressured reservoirs, resulted in ineffective well control during the workover.
The CSB also determined that ineffective ignition source management contributed to the fire that caused the fatalities and injuries. The lack of comprehensive federal regulations for onshore oil and gas operations was identified as a contributing factor to the incident.
Watch our podcast to learn more about the incident;
Read the Final Report from CSB on Wendland 1-H Well Blowout Incident – FINAL REPORT: Wendland Final Report
