Often I find myself asked to explain my job as a production engineer to someone outside of the industry. Instead of a long technical description involving rock mechanics, fluid properties, and artificial lift, I respond by saying that I’m a well doctor. I examine sick wells, diagnose the symptoms, review the case history, and prescribe the remedy.
Wells come in all shapes and sizes, from newborn to geriatric, with different production targets depending on their age, condition, and specific geologic makeup. Oftentimes I have heard the field hands refer to their wells as “children”—they can be docile and dependable, or fractious and temperamental. Some wells need a delicate hand, while others will produce without issue until the day they suddenly die—or reach the end of the economic life, which often comes first.
The first indicator of a problem often lies with a drop in production, which a good surveillance program should detect. Wellhead telemetry and up-to-the-minute production data mean that we can check the vital signs without ever having to set foot on a well pad. A robust well review program ensures that even healthy wells receive (at the very least) an annual check-up.
The best well reviews should involve the field operator, who will be able to relay any “pre-existing conditions” about the well (e.g., difficulty accessing the site, a local herd of cattle, comments made by regulatory inspectors, evidence of wax or scale). Action items can be assigned and prioritized, and production targets set based on a decline curve analysis.
Fortunately, a majority of production problems can be corrected by “noninvasive” procedures: Fixing surface equipment (relatively simple for onshore wells), removing a bottleneck in the line, replacing a glitchy sensor, etc.
Other issues require followups: Samples should be taken to determine such chronic problems as scale and wax, and lab work may become necessary, i.e., cross-functional support from a flow assurance team really comes into play here. A chemical treatment program may be prescribed (the well version of Lipitor, a cholesterol-management drug).
The more serious cases do require invasive procedures—and sometimes there can be a long wait-list for a workover rig. Offshore intervention may require a convergence of many functional experts—the perfect storm of availability, funding, and timing. After exhausting all treatment options, some wells simply do not have a viable future. Sadly, well doctors also deal with terminal cases, making recommendations for end-of-life arrangements.
As a well doctor, the fun cases involve reaching out to a specialist; perhaps a more senior engineer, the rig supervisor or a geologist—to discuss installing artificial lift, restimulating the rock, or a water shutoff. These require more research and justification for the expenditure, and are less routine than replacing a tubing string. Whenever possible, I would make it a point to oversee the implementation of those specialty operations.
No doctor’s office would be complete without patient records. Well files come in all shapes and sizes. There’s the chronic patient with the bulging file, who seems to need a workover every year or two, and then there is the patient who has never needed so much as a tubing change (if you can believe it), but at nearly 60 years old could probably use a facelift.
Regardless of whether or not there were electronic files available, I would always check the physical well file—you never know what you might find. Although my former company kept most records electronically, I was a big believer in the importance of the written record—I saw far too many files containing obsolete floppy discs to want to heavily rely on the technology du jour for permanent records. (As the business unit is currently being sold to another company, I have to wonder just how many of those electronic records will be passed along.)
As engineers we wear many hats, but above all, we solve problems. The profession of well doctor is a noble calling. I hope that if you are a production engineer, you appreciate this playful metaphor and will consider explaining your job in these terms to others outside our industry.
Kristin Cook is the deputy managing editor of TWA. Cook is currently pursuing a master’s degree at the University of Texas at Austin (class of 2020) focusing on global energy policy. She was previously a production engineer with 5 years of experience. Her skillset includes implementing artificial lift, optimizing base production, and managing daily operations of tight gas sands and coalbed methane wells.