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 ...

BACKGROUND This study aimed to investigate, by means of finite element analysis, the effect of a drill hole at the end of a horizontal osteotomy to reduce the risk of lateral cortex fracture while performing an opening wedge high tibial osteotomy (OWHTO). The question was whether drilling a hole relieves stress and increases the maximum correction angle without fracture of the lateral cortex de...

We use laser hole drilling to assess the mechanics of an embryonic epithelium during development-in vivo and with subcellular resolution. We ablate a subcellular cylindrical hole clean through the epithelium and track the subsequent recoil of adjacent cells (on ms time scales). We investigate dorsal closure in the fruit fly with emphasis on apical constriction of amnioserosa cells. The mechanic...

A century ago, in 1909, Martin Kirschner (1879-1942) introduced a smooth pin, presently known as the Kirschner wire (K-wire). The K-wire was initially used for skeletal traction and is now currently used for many different goals. The development of the K-wire and its insertion devices were mainly influenced by the change in operative goals and by the introduction of antibiotics. The first versi...

* Supported in part by Brite Euram project BE7470. Abstract The two-level fuzzy-lattice (2L-FL) learning scheme is introduced for application on an intelligent surgical (mechatronic) drill in the stapedotomy surgical procedure in the ear. The 2L-FL scheme learned from past cases to evaluate pointedly the thickness of a stapes bone using a force/torque pair of drilling profiles. Hence it is poss...

Effective cuttings transport means a better hole cleaning in drilling operations, which can increase the rate of penetration (ROP), and avoids pipe sticking, higher drag and torque problems. This paper aimed to analyze cuttings transport efficiency affected by different blade shapes of stabilizers, which is often overlooked in drilling. For this purpose, Eulerian multiphase flow model was used ...

Unsaturated polyester resin (UPR) has the resistance against boiled water, acid and alkali, and hence, is widely used in corrosive environment and elsewhere, although fracture strength of polymeric materials is generally low relative to metals and ceramics. Despite the fact that polymer components are mostly produced near-net-shape, machining, particularly drilling, is often required to prepare...

Automation and optimization of the manufacturing processes play an important role in enhancing productivity. For this, monitoring and diagnostic systems are becoming increasingly necessary to asses the response of materials in manufacturing. In this paper, acoustic emission (AE) sensing was employed for on-line detection of workpiece status and to improve the process stability and workpiece qua...

The Cajon Pass Scientific Drilling Project is a broad, interdisciplinary experiment involving over two dozen principal scientists. Phase I of drilling, coring and downhole experimentation began Dec. 8, 1986 and ended Apri12, 1987 with the hole at a depth of 2115 m, 82 m of core recovered and a wide range of downhole experiments successfully completed. In this paper we briefly outline the scient...