Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced. The diffusion coefficient of shale ...

The past decade has seen increased focus on nanoparticle (NP) based drilling fluid to promote wellbore stability in shales. With the plugging of NP into shale pores, the fluid pressure transmission can be retarded and wellbore stability can be improved. For better understanding of the interaction between shale and NP based drilling fluid based on previous pressure transmission tests (PTTs) on A...

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...

Geopressure evaluation or prediction is an important exercise that must be carefully estimated when planning a drilling campaign. Formations of high pressure regime can be experienced in several areas within the bore hole depths. Being unaware of these areas that experience high pressure regime can create many uncontrolled events such as blow outs that may lead to human and material loss within...

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...

Designing drilling fluids for drilling in deep gas reservoirs and geothermal wells is a major challenge. Cooling drilling fluids and preparing stable mud with high thermal conductivity are of great concern. Drilling nanofluids, i.e. a low fraction of carbon nanotube (CNT) well dispersed in mud, may enhance the mixture thermal conductivity compared to the base fluids. Thus, they are potentially ...

With rapidly growing global demand for energy resources, oil and gas exploration & production companies face mounting pressure to maximize supply and increase the rate of discovery for new energy sources. Increasingly operating in more remote locations and investing heavily in equipment and facilities, companies face greater financial and operational risks than ever before. Optimization of dril...

The main task of drilling the formation by the bit is done via scraping, crushing and grinding. Discharging the fluid from the bit nozzles is done with high pressure which assists to break the rocks. Different parameters affect the bit selection and design for each drilling formation, but the most important one is drillability that depends on hardness of the formation. In this paper, the design...

Multiple drilling is reported to be an effective treatment for osteonecrosis of the head of femur, but its effect on intra-osseous pressure has not been described. We undertook multiple drilling and recorded the intra-osseous pressure in 75 osteonecrotic hips in 60 patients with a mean age of 42 years (19 to 67). At a mean follow-up of 37.1 months (24 to 60), 42 hips (56%) had a clinically succ...

control of well drilling operations poses a challenging issue to be tackled. the loss of well control could lead to the occurrence of blowout as a severe threat, involving the risk of human lives and environmental and economic consequences. conventional proportional-integral (pi) controller is a common practice in the well control operation. the small existing margin between pore pressure and f...