Drilling advances

	Vol. 227 No. 6
LES SKINNER, PE CONTRIBUTING EDITOR

Systemic thinking and the drilling rig. Most people outside the industry, and some inside the industry, consider a drilling rig to be a just big, noisy machine designed to drill a hole in the ground, while being as annoying as possible. Few people understand that a rig is a complex, coupled, multi-variant system with lots of parts and pieces all skillfully joined to drill a well as efficiently as possible.

Drilling rigs employ multiple systems within a rig, including electrical, pneumatic, hydraulic and mechanical systems. Each of these systems is linked to all the others. For example, the pneumatic system uses compressed air to run hoists and tuggers, clutches in the drawworks, the old-style “automatic driller” and the kelly spinner. The loss of rig air, or one device using too much air, can cripple some other portion of the rig that needs compressed air. Here’s another one: try to operate a BOP stack without pressured hydraulic fluid from the closing unit. It runs off rig air, too, along with electricity.

The mains pump mud down the drillpipe and out the annulus to clean the hole, lubricate the drillstring and clean the hole. The mechanical hoisting equipment lifts and turns the drillstring. The electrical system lights the rig, runs the pump motors and the drawworks on some rigs, keeps the mud mixed in the steel pits and provides communication. Electricity is used in the quarters. It also keeps the toolpusher’s coffee pot hot, a crucial element in a successful drilling operation.

Because of our limited perspectives, each of us thinks of the rig as a collection of these various components, but few see the entire rig as a complex system. Change something in one area, and chances are something else will need to be changed. For example, increase the electrical power to the drawworks and the lights dim in the galley. Does that really bother anyone? Not unless you’re the cook and you happen to be working with an electric stove that suddenly cools, so the food doesn’t cook. How about controls, radio equipment and computers that are starved of electricity? They have internal protection that might just shut them down.

A drilling rig is like a human body with all of its interlocking systems. The circulatory system is affected by the respiratory system. The digestive system is affected by the nervous system (anyone who’s had a teenager stay out too late at night knows about this). If the endocrine system fouls up, then the whole body gets out of balance. They tell me there is a lymphatic system, too, but I have no idea what it does. The point is: a change in one system affects all the others. Without proper balance between them, the body suffers.

The trend in medicine is toward specializing. There are internists, orthopedists, respiratory specialists, endocrinologists, neurologists, dentists, proctologists, podiatrists and a whole bunch of other “-ists” that like to treat just their particular area of the human body. The result is that many of us take medications for one problem that are contra-indicated for some other part of the body. So we end up “sufferin’ what we’re sufferin’ from, and sufferin’ from the cure” to borrow a line from a Broadway musical.

Rigs are the much the same. We have bit specialists, mud specialists, directional drilling specialists, logging specialists, pump specialists, well control specialists and a whole bunch of other “-ists” that like to deal only with their particular area. The result is that often our drilling operation ends up with self-inflicted injuries that can cripple the rig’s ability to perform its basic function.

Mud men want to optimize the drilling fluids, but what does that do to the pumps? The bit man may recommend a more aggressive bit, but can the mud system carry increased cuttings out of the hole and separate them at the surface. The mud man can’t understand why the pumps aren’t doing the job. The bit man doesn’t understand why the mud is so poor. The rig mechanic and electrician don’t understand why they won’t just quit changing stuff around. We all see our own small area of expertise as a tiny silo not connected to any other system. So, we try to fix the system by fixing our own little parts without fully grasping the situation. Toolpushers can’t do it, company men can’t do it, the electrician, the mechanic, the bit man, the mud man, the well control man . . . you get the idea.

The worst of the group is the drilling engineer. We (and I am one, incidentally) are taught in college to break a complex system down into its component parts. Then we analyze each component separately, optimize (fix) each one independently and put the whole thing back together. If each component works properly, the entire system should work splendidly. Right?

Wrong. It rarely works that way, because we have not considered all the intricate competitions and synergies intrinsic to these complex, coupled systems. We are too busy trying to fix the parts of the system and not the system as a whole. So what is the answer?

Drillers. These are the people at the controls who understand far better than anyone else how the components work together as an integrated system. Back in the “old days” (10 – 15 years ago or so), we were content to let drillers “tweak” the rig’s drilling parameters to find the sweet spot that allows the entire system to operate at maximum performance. Now we give the driller a program and insist that he/she stay within the boundaries outlined in the plan. When the system doesn’t respond the way we think it should, we blame the driller. Perhaps we should rethink our procedures a bit.

Some would say that this concept worked back in the “old days” when drilling was somewhat routine (as if it ever was). Now, with our forays into deep, high-pressure, high-temperature, extended reach, underbalanced operations, the driller may need more direction from the specialists to ensure that drilling goals are met. My own recent experience certainly indicates that to be the case. I still believe in drillers, however.

The solution will probably involve all the various specialties becoming more adept at systemic thinking – getting out of the silo and learning what it means to be part of an integrated solution. This will happen, anyway, as the current group of specialists becomes more experienced. The only problem with experience is that it takes so much time to get it, and we have precious little time to spare, if we are to keep pumping oil and gas to an energy-hungry world.