Drilling advances
Situation awareness and well control. The child watches the tennis ball roll into the street. She stops at the curb and looks up and down the street. She sees the black pickup but doesn’t recognize that it is moving way too fast for her to safely retrieve the ball. The pickup driver has just turned off the highway and doesn’t realize how fast he’s going. He is distracted by the ringing cellphone and reaches down to answer it. He doesn’t see the little girl until it’s almost too late. Both of the participants in this scenario are suffering from a common problem: they aren’t quite sure about the circumstances in which they suddenly find themselves. Both are experiencing poor situation awareness. Situation awareness (SA) is a relatively new field of human factors study that is concerned with how well humans know what’s going on around them. Dr. Mica Endsley defined situation awareness several years ago, and her definition is often quoted, i.e., “The perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future.” Certainly, when it involves driving in a residential area, or in well control during drilling operations, this definition has considerable significance. Training, drills and exercises emphasize early kick detection and quick reactions to limit the size of the kick entering the wellbore in all rig operations, whether drilling, tripping or performing work with the drillstring out of the hole. Pit volume totalizer systems, flow detectors and trip tanks help in determining when a kick occurs. These systems have become considerably more sophisticated over time. They can be set to detect the tiniest of kicks and transmit that information quickly to operating personnel. Screens with flashing displays, horns or other alarms and messages can be transmitted literally at the speed of light. So, the first part of Dr. Endsley’s definition is satisfied on rigs with these systems. What about the other two parts? How well do modern-day drillers perceive what a kick in the hole means and how well can they project what will occur over the next few minutes, hours or days? Where do they go to develop the skills necessary to make these determinations? In the world of well control, specialist companies have quoted the informal statistic for several years that more than 95% of all blowouts result from human error. Experience inside this specialized industry has shown that even when a complete loss of pressure and flow containment does not occur, many kicks are mishandled. What should be a simple kick circulation can quickly turn into a “near miss” with respect to well control loss. I submit that in most well control incidents, drillers rarely make bad decisions or perform poorly in handling kicks. They just don’t fully grasp the situation, so they apply a procedure (properly) that does not fit the particular circumstances of the kick. Perception is the issue – they just cannot determine what’s going on downhole from the available indications at the surface. In other words, they just can’t see far enough down the hole to know what to expect next. This perception issue has been reported in the past on CO2 blowouts. Supercritical CO2 has fluid properties near its critical point that make a minor kick on these wells almost explosive in nature as it expands in the wellbore. Mud columns can be evacuated in a matter of seconds (minutes at the most). High flowstream velocities have been recorded by emergency responders, with marble-sized dry ice particles ejected from the wellbore at the speed of sound. The same problem is well-known when drilled gas is dissolved in oil-base drilling fluids. Gas remains in solution as the fluid is circulated up the hole until the bubble point pressure is reached. Then a violent kick occurs as gas bursts out of solution in the upper portion of the hole. Situation awareness is improved by experience. It becomes much easier to perceive and project if one has had occasion to live through one of these events. Recently, researchers have identified an area of the brain called the anterior cingulated cortex (ACC) that monitors the circumstances in which a person lives. When changes occur in the individual’s surroundings that hint at danger, signals are quickly sent to other portions of the brain, resulting in discomfort, irritation and heightened alertness. All of this occurs in the subconscious mind outside the normal thought process that commonly deals with problems, according to the researchers. Most people who have worked on a drilling rig have experienced signals from this “sixth sense.” We’ve all heard that tiny voice that warns us that something is wrong, although we can’t identify what it is. The more complex the task, the more persistent is that voice. What’s the answer for developing better situation awareness for rig operating personnel? Well-control simulators have been used for years to provide a means of introducing a problem into kick circulation. The old analog simulators had circuits deliberately included that provided accurate indications of a plugged jet, hole in the drill pipe, secondary kick introduction and a variety of other problems. The newer digital simulators have similar capabilities. Sadly, these are only used during well-control training that occurs every two years or so (if at all). “Pit drills” are often used to provide hourly, daily or weekly well-control proficiency. While the scenario for these drills can be planned to include some type of problem, the crews just don’t have the opportunity to actually see and feel what goes on in the real event. The aviation industry has come up with a good solution for improving pilot situation awareness. They put the student pilot in a simulator with controls, gauges, alarms, displays and all the other accoutrements of a cockpit, and let the pilot “fly” the plane. Then, an instructor causes a failure of some type to occur. This provides the student with a realistic situation accompanied by sound, vibration and motion, as the entire simulator rolls and pitches with the help of hydraulic cylinders supporting the “cockpit.” All of this, of course, is controlled by computers, and “crashes” rarely hurt the student. Maybe we should adopt similar training for young driller wannabes to improve situation awareness involving kicks and other well-control problems. Incidentally, the pickup didn’t hit the little girl. I know- – I was the driver. Les Skinner, consultant, Houston, and a chemical engineering graduate from Texas Tech University, has 32 years’ experience in drilling and well control with major and independent operators and well-control companies.
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