Drilling advances

	Vol. 229 No. 1
LES SKINNER, PE, CONTRIBUTING EDITOR, LSKINNER@SBCGLOBAL.NET

Drilling software. There has been an upsurge in development of and interest in software products to enhance the drilling process over the past several years. At the recent SPE Annual Technical Conference and Exhibition, new software products were demonstrated that made drilling engineers almost giddy with excitement. The capabilities of these programs, their improved user friendliness and output varieties were something to behold.

I am from the generation that made it through college with a slide rule; I didn’t get my first handheld calculator until I had been practicing for almost two years, and it only had arithmetic functions. So, I’ve had the opportunity to see various tools used throughout drilling software development. It’s been quite a ride.

My first exposure to drilling software was Optimized Drilling, a program prepared by our research department in Tulsa. It ran on an IBM 360 Mod 50 mainframe computer over telephone lines. By modern standards, it was cumbersome, slow and about as user friendly as a left-handed torque wrench. Still, we were able to enhance drilling performance using it (after a directive from Tulsa saying that it would be used on all future drilling, of course).

Drilling software went through a variety of development phases. Only the majors could provide the massive computers needed for the early packages. There was no computer capability in the field. The rest of the industry developed smaller, but still robust, tools. One of these was the programmable calculator. If a driller was crafty, he could input various equations to calculate things like mud properties, casing depth limitations and weight on bit after deducting friction and buoyancy, just by pushing the EXEC key. Wow! What a marvelous advance.

The spread of programmable calculators resulted in books of utility programs. One could sit at his/her desk and spend hours copying programs from a published paper into the calculator, test it, and then archive the program on thin magnetic media strips.

Those of us who were a little skeptical of others’ programing skills would take the programs, add a subroutine or two, modify an equation and debug the new program. Eventually, we would give up, go back to the original version and use it for a while.

And then, came the PC. My first personal computer was essentially an upgraded typewriter (for those of a later generation, a typewriter was a mechanical device that used small hammers with raised faces to sequentially print letter, number or symbol images on paper). The PC was slow, had only a few megabytes of internal storage and used 5½-in. “floppy” magnetic disks to archive. The entire memory of these old computers and all the magnetic disks could be wiped out by any nearby magnetic field. It was not a reliable system for long-term retention.

Executing any program on these relics was difficult. They had internal programs preloaded that were useful for archiving Grandma’s recipes, calculating expenses and balancing checkbooks. You simply could not change them. Writing a new program for the old PCs was not satisfying. The programs could not be run except in DOS (Disk Operating System), and fouling up the entire operating system was a very real possibility. I did it on more than one occasion, complete with wailing and gnashing of teeth.

As PCs and software improved, entities from the service sector and academia provided drilling programs for individual drilling processes. Hydraulics was an early favorite, because fluid flow was well understood by Reynolds, Prandtl, Fanning, Aristotle and Plato.

Then came the integrated drilling software packages. They were commercial and, again, user unfriendly. One would input various well designs, mud properties and bottomhole assemblies, and then push the EXEC button. One could then go to lunch, run a few errands, attend two or three meetings, meet with HR, get the car repaired, go to the gym, bake cookies, get a cup of coffee and then check to see if the program had finished. Often, there was a longer wait involved. They were slow.

Sometimes results were reasonable, sometimes gibberish was printed and frequently an error message of unknown type on the 10-in. screen was all that met the user’s glare. The trick was to alter the input ever so slightly to make it program acceptable and re-execute the job, often with similar results after an even longer delay. It was a cinch that nobody but the programmer understood what was in the software. After all, it was proprietary and the supplier could not possibly tell a user what equations were used. In short, a lot of the early software was completely unusable.

Over the last few decades, joy has entered the drilling software world. I recently ran a search on drilling software. The variety and capabilities of modern software are astounding. Here is a partial list of variables that can be calculated: geosteering, directional analysis, horizontal lateral control, drillstring vibration, drilling optimization, drilling rig investment analysis, weight on bit, kick tolerance, hole geometry, borehole stability, circulation restoration methods, equivalent circulating density, cementing, torque and drag, pore pressure/fracture gradient prediction, coiled tubing drilling, tubular design, bit selection, air drilling, multi-phase fluid drilling, washout locator, ton mile inventory, tank volumes, swab/surge, UBD/MPD, deepwater drilling, extended-reach drilling, dynamic kill, drillstring failure modes, triaxial stress, displacements and well control.

It seems now that everyone has an integrated package. One simply inputs the basic data, and the software spits out the answer. Sadly, most of the integrated packages do not allow for sensitivity analysis in a single run. The input variables must be changed and a new run made for each new variable. Like the old software packages, this takes lots of time, costing both money and frustration. Still, I am very much encouraged by the direction I see the drilling software industry taking. It beats the slide rule any day.

I am compelled to caution computer enthusiasts here. Remember, no matter how glamorous and exotic the software, disregarding all the nifty output charts with all the pretty colors and ignoring all the whistles and bells, the computer is still nothing but a high-speed idiot. A person will always be needed in the process. Only humans can exercise the judgment necessary for a successful drilling operation.