In this article, we propose control solutions to suppress undesirable torsional oscillations of the drill string in oil well drilling systems. Two feedback control laws are derived from Partial Differential Equations (PDE) models capturing the main features of the so-called stick-slip phenomenon. Comparative simulations highlight the merits of the two approaches.

Formation of hydrates is observed during drilling and construction of wells, more frequently in gas wells located offshore (deep sea water). Hydrates of natural gas can clog chokes and kill lines, and obstruct the opening or closure of blow out preventer (BOP), seal well override valve and immobilize well string. Because of that, this work was mainly focused in the selection and adaptation of a...

Background & objectives: Oil well drilling operations are subject to various occupational hazards because of their nature and type of activities, which causes illnesses, loss of workforce as well as a lot of financial losses to the economic system of the community. Therefore, it is essential for all employees to observe safety in order to protect manpower and equipment. The purpose of this stud...

Recently, we have seen falling oil prices combined with sticky costs at a high level in the petroleum industry. This cause cost cuts and project postponements, thus challenging reserve replacement of oil companies and security of supply for consumers. Costs are particularly high for drilling. High rig rates are obviously important. In new contracts for high-spec semi rigs on the Norwegian Conti...

This paper explores the possibility of developing early warning indicators based on incident investigation. The use of early warning indicators may contribute to ensure that oil companies produce oil and gas without harmful spills. The incident investigated was a hydraulic oil leak from the Eirik Raude drilling rig during exploration drilling in the Barents Sea in April 2005. The incident is an...

Environmental impact is a primary criterion for selecting any liquid used for filling boreholes in glaciers. Antifreeze solutions based on ethanol and other high molecular weight alcohols are among several potential fluids used for drilling deep holes in the Arctic and Antarctic glaciers. At relatively high ice temperatures in boreholes, the concentration of ethanol in the solution can be low. ...

Recovery from disturbance in deep water is poorly understood, but as anthropogenic impacts increase in deeper water it is important to quantify the process. Exploratory hydrocarbon drilling causes physical disturbance, smothering the seabed near the well. Video transects obtained by remotely operated vehicles were used to assess the change in invertebrate megafaunal density and diversity caused...