Drilling-induced delamination is among the major concerns of applying the fiber-reinforced composite materials in various industries. Core drill ossesses the advantage for reducing the delamination by distributing the drilling thrust force toward the drill periphery. The thrust force of core rill varying with the conditions in drilling carbon fiber reinforced plastic (CFRP) is experimentally in...

Drilling of fiber reinforced plastics is necessary in order to assemble complex/intricate composite products. Drilling induced damage leads to high percentage of part rejection and reduced product efficiency and life. The thrust force and torque have been found to be the important factors influencing damage. In the present research endeavor, an attempt has been made to develop a fuzzy rule base...

In this study, synthetic sulfonated polymers were used in order to enhance the rheological properties of drilling fluids. The capability of these polymers in reducing the effects of environmentally friendly, but harmful, pollutants such as cement, calcium chloride, gypsum as well as pH changes were investigated. In the present work, two sulfonated synthetic polymers, namely Polythin and Polydri...

Calculation of the specific charge and specific drilling before a blasting operation plays a significant role in the design of a blasting pattern and the reduction of the final extraction cost of minerals. In this work, the information from the Sungun, Miduk and Chah-Firouzeh copper mines in Iran was assessed, and it was found that there was a significant relationship between the specific charg...

A detailed understanding of the drilling system and the drilling control is required to correctly interpret rock mass conditions based on monitored drilling data. This paper analyses data from hydraulic in-the-hole (ITH) drills used in LKAB’s Malmberget mine in Sweden. Drill parameters, including penetration rate, percussive pressure, feed pressure, and rotation pressure, are monitored in under...

Filtration of the drilling mud is one of it's most important parameters, especially when drilling-in producing formation. Decrease of filtration characteristics allows reducing both solid and liquid phases's penetration zone into the formation. The study of the effect of the weighting-bridging agent's fractional composition on the filtration rate allows selecting of optimal composition of the s...

The dogleg severity is one of the most important parameters in directional drilling. Improvement of these indicators actually means choosing the best conditions for the directional drilling in order to reach the target point. Selection of high levels of the dogleg severity actually means minimizing well trajectory, but on the other hand, increases fatigue in drill string, increases torque and d...

Stick-slip vibrations present at the bottom hole assembly (BHA) of a generic oilwell drillstring subject to dry friction are studied. Different nonlinear differential equations-based models of a drillstring are analyzed. The drillstring models presented are oriented to avoid simulation problems due to the discontinuities originated by the presence of dry friction. The influence of different dri...