In rotary drilling operation, the hydraulic circuit typically consists of stand pipe, rotary hose, swivel, Kelly, drill pipe, drill collar, drill bit, and the annulus between the drillstring and the open hole or the casing. Stand Pipe Pressure, abbreviated as SPP, is defined as the total frictional pressure drop in the hydraulic circuit. SPP, an important drilling parameter in selecting proper ...

Good flow and pressure control is essential for successful Underbalanced Drilling (UBD) operations. This work evaluates the use of Model Predictive Control (MPC) for integrated control of well conditions and the topside separation system during UBD. The downhole well pressure, separator liquid levels, and the separator pressure are controlled by manipulation of the rig pump, the choke, and the ...

The first stage to have access to a reservoir is the drilling operation. The proper development of this operation plays a major role in increasing productivity. It must be pointed out that the drilling fluid (mud) is pivotal in achieving this objective. Among these fluids, water-based fluids are the most common ones, which have been utilized to drill approximately 80% of all wells and are m...

BACKGROUND The present study aimed to explore the relationship between surgical methods, hemorrhage position, hemorrhage volume, surgical timing and treatment outcome of hypertensive intracerebral hemorrhage (HICH). METHODS A total of 1 310 patients, who had been admitted to six hospitals from January 2004 to January 2008, were divided into six groups according to different surgical methods: ...

Composite materials are widely employed in the naval, aerospace and transportation industries owing to the combination of being lightweight and having a high modulus of elasticity, strength and stiffness. Drilling is an operation generally used in composite materials to assemble the final product. Damages such as the burr at the drill entrance and exit, geometric deviations and delamination are...

The vibration phenomenon represents the cause of many problems in metal cutting processes. It has a big influence on the quality of the machining operation, tool life and machine precision. Drilling operation is a common metal cutting process where quality of the hole form is often a critical issue. Therefore, it was necessary to predict these vibrations. The first part of this paper deals with...

this study was conducted during two years (2007-2009) in shawoor agricultural research station on a silty-clay soil. experiment conducted in split plots in a randomized complete blocks design in three replications. main plots were planting methods including centrifugal broadcaster (p1), centrifugal broadcaster + furrower (p2), seed drill (p3), seed drill + furrower (p4), three lines bed drillin...

conclusions our results showed that only 17% of the measured points in the oil drilling rig floor were in safe area; 39% were in caution area and 44% were in danger area. in the camp facilities area, 51% of the points were in safe area, 38% were in caution area and 11% in danger area. the main sources of noise exposure in the rig floor area were power generators. materials and methods this was ...