Today, a large part of the energy input at the drilling rig floor may never reach the drill bit. Instead of cutting rock, energy is lost through friction, mechanical shock and vibration—all of which can lead to premature failure of downhole equipment, longer drilling times and higher economic and technical risks. Indeed, the motion of thousands of meters of spaghetti-like pipe in a wellbore a few tens of centimeters in diameter is prone to all manner of mechanical behavior that is only becoming understood today. In fact, studies have shown that improvement in the management of energy input at the surface can increase downhole tool reliability by a factor of two or three.

 

 

Achieving a step change in drilling performance begins with recognizing the three key objectives of the workflow. The first of these is increasing overall drilling efficiency, which is a function of the rate of penetration and the overall time actually spent drilling. The second is precise well placement and formation evaluation to maximize production and provide quantitative reservoir characterization. The third objective is wellbore evaluation and assurance, defined as the need to protect the integrity of the well throughout its productive life.

 

Reaching these objectives requires a move from regarding drilling as an art form to thinking of it as a science. As such, a much greater degree of optimization is necessary across the drilling workflow, from the development of technology through its application in the field.