wellbore instability is a quite common event during drilling, and causes many problems such as stuck pipe and lost circulation. it is primarily due to the inadequate understanding of the rock properties, pore pressure, and earth stress environment prior to well construction. this study aims to use the existing relevant logs, drilling, and other data from offset wells to construct a precise mech...

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...

The aim of this paper is to utilise genetic algorithm approach to investigate the effect of CNC drilling process variables such as spindle speed, drill diameter, material thickness, and feed rate on thrust force and torque generated during the drilling of mild steel plate using H.S.S drill. To find out the relationship between drilling process variable on thrust force and torque generated to th...

fluid properties with constant improvement in efficiency have been noticeable as important criteria in drilling operation. the main drilling fluid properties highly depend on utilization of new polymers with high efficiency in drilling fluid composition. in this paper, the performance of a new polymer, called partially hydrolyzed polyacrylamide polymer (phpa), is studied which has recently ente...

Drilling activities in the oil and gas industry have been reported over decades for thousands of wells on a daily basis, yet the analysis of this text at large-scale for information retrieval, sequence mining, and pattern analysis is very challenging. Drilling reports contain interpretations written by drillers from noting measurements in downhole sensors and surface equipment, and can be used ...

objective: to determine the efficacy of ovarian drilling in pco patients who failed to achieve pregnancy with medical treatment. methods and main results: 75 patients with a diagnosis of pco of whom 48(64%) were primary infertile and 27(36%) were secondary infertile were clomiphene resistant. the other methods like bromocriptin, gonadotropins, gnrh -a and metformin had been given to these patie...

Drilling performance prediction, using traditional mechanics of cutting approach, is based on the extension of three-dimensional oblique cutting theory. The quantitative reliability of such conventional models depend on a numerous number process variables and quantitative accuracy of the data bank for a given work material. The complexity of such models is increased when inevitable eccentricity...

Objective: To determine the efficacy of ovarian drilling in PCO patients who failed to achieve pregnancy with medical treatment. Methods and Main Results: 75 patients with a diagnosis of PCO of whom 48(64%) were primary infertile and 27(36%) were secondary infertile were clomiphene resistant. The other methods like bromocriptin, gonadotropins, GnRH -a and metformin had been given to these ...

A mathematical model has been developed to predict the temperature distribution in wellbores either offshore or inshore. It is incorporated the different activities encountered during drilling operations. Furthermore, the effect of drill collar and casings and bit rotating in a well during completion has been considered. The two dimensional approach is presented in the form of a computer progra...

Micro drilled holes are utilized in many of today's fabrication processes.Precision production processes in industries are trending toward the use of smaller holeswith higher aspect ratios, and higher speed operation for micro deep hole drilling. However,undesirable characteristics related to micro drilling such as small signal-to-noise ratios,wandering drill motion, high aspect ratio, and exce...