This paper presents a wellbore-stability study of the San Andreas Fault Observatory at Depth (SAFOD) research borehole located near Parkfield, California, USA. In the summer of 2005, the SAFOD borehole was drilled successfully through the active trace of the San Andreas Fault (SAF) in an area characterized by fault creep and frequent microearthquakes. In this study, we report how the analysis o...

fluid invasion from water-based drilling mud (wbdm) into the shale formations causes swelling,high pressure zone near the wellbore wall, and eventually wellbore instability problems duringdrilling operations. for the stability of the wellbore, physical plugging of nanoscale pore throats couldbe considered as a logical approach toward avoiding the fluid invasion into the shale formation. thispap...

The problem of slow drilling in deep shale formations occurs worldwide causing significant expenses to the oil industry. Bit balling which is widely considered as the main cause of poor bit performance in shales, especially deep shales, is being drilled with water-based mud. Therefore, efforts have been made to develop a model to diagnose drilling effectivity. Hence, we arrived at graphical cor...

maybe viscosity in drilling fluid is the most important parameter because cutting removal from well are task of viscose fluid. if viscosity of fluid is less than particular value, cutting will settle down in well and drilling operation will be stopped. in this study, synthesis of alumina/polyacrylamide nanocomposite through solution polymerization method was performed. rheological behavior of m...

Horizontal directional drilling (HDD) is widely used in soil and rock engineering. In a variety of conditions, it is necessary to estimate the torque required for performing the reaming operation. Nevertheless, there is not presently a convenient method to accomplish this task. In this paper, to overcome this difficulty based on the basic concepts of rock engineering systems (RES), a model for ...

Formate drilling and completion fluid system is a new type of clean organic salt brine system which has been developed from inorganic salt brine drilling fluid system. It is beneficial to protecte and find hydrocarbon reservoir. Due to the solid free system, the damage of solid phase particles on reservoir, especially low permeability oil and gas layer, can be greatly eliminated, at the same ti...

BACKGROUND Integrated Ocean Drilling Program Expedition 338 was the second scientific expedition with D/V Chikyu during which riser drilling was conducted as part of the Nankai Trough Seismogenic Zone Experiment. Riser drilling enabled sampling and real-time monitoring of drilling mud gas with an onboard scientific drilling mud gas monitoring system ("SciGas"). A second, independent system was ...

In drilling operation the design of a proper mud weight to avoid any instability’s is important. A low mud weight may cause breakouts around the borehole whereas a high mud weight can fracture the formation. Mud weight design is based on two main factors: the mechanical properties of formations being drilled and the state of in-situ stresses in the field. While drilling in soft formations are t...