Abstract: A sealing device is for sealing fluid transmittable openings in well components. The sealing device includes an elastic element which is arranged between two shoulders. The elastic element, before being placed in the fluid transmittable opening, has a larger external dimension than the fluid transmittable opening to be sealed. A gap is arranged between at least one of the shoulders and the elastic element, allowing liquid to enter between the shoulder and the elastic element. The ridge is arranged on an intermediate piece which is located between the shoulder and the elastic element. The intermediate piece is constituted by as ring in which the ridge is surrounding and divided, and projects from an end surface opposite an abutment surface facing the elastic element.

Abstract: A device for the pressure regulation of a well is provided with a return pump for drilling fluid. The operating level of drilling fluid in an annulus which is fanned between an outer pipe and an inner pipe is at a height level between the upper portion of the outer pipe and the bottom portion of the well. The return pump is in the annulus.

Abstract: A method is for determining the position of a lower portion of a drill string in a bore hole. The drill string comprises a number of drill string components, each drill string component being interconnected by means of at least one joint. Several ultrasonic sensors are arranged after each other along a drill string. The method comprises localizing the position of the chamfer of the joint relative to the ultrasonic sensors.

Abstract: An earth model comprising a plurality of regions in geological space; associated with each said region in geological space, at least one parameter function defined over a region in parameter space; associated with each region in geological space, at least one transformation which maps coordinates within the region of geological space to coordinates within the region of parameter space. This gridless approach to earth modelling allows much easier alteration of the structural model and the parameter data independently of each other, facilitating multiresolution evaluation of the model as well as easy production of multiple geological interpretations.