Abstract: A tubular element for a drill stem includes a substantially cylindrical body and two tool joints. Each tool joint is disposed at one end of the body and provided with a threaded portion that can be joined to a complementary element. At least one of the tool joints has a lifting surface that can cooperate with a lifting tool of the element to connect it into a drill stem. The lifting surface has a non-circular cross-section forming an activation zone for a drilling fluid.

Abstract: Method for designing a corrugated roofing sheet made of natural fibers, impregnated with bitumen including a uniform pattern of mutually parallel alternating corrugations borne by a mid-plane, the corrugations defining rounded crests each separated from the next by a rounded trough, the crests and trough being connected by alternately inclined portions, the transverse offset between two successive crests being equal to the transverse offset between two successive troughs and defining the pitch P of the corrugations, the sheet having a thickness E of material substantially constant over its extent, and a height H being twice the distance between the mid-plane and the exterior surface of a crest or twice the distance between the mid-plane and the exterior surface of a trough, these two distances being identical. The height, thickness and pitch values are determined by Fi<H3/(8×E×(H+P))<Fs, where Fi=25 mm and Fs=35 mm.

Abstract: Method for designing a corrugated roofing sheet made of natural fibres, impregnated with bitumen including a uniform pattern of mutually parallel alternating corrugations borne by a mid-plane, the corrugations defining rounded crests each separated from the next by a rounded trough, the crests and trough being connected by alternately inclined portions, the transverse offset between two successive crests being equal to the transverse offset between two successive troughs and defining the pitch P of the corrugations, the sheet having a thickness E of material substantially constant over its extent, and a height H being twice the distance between the mid-plane and the exterior surface of a crest or twice the distance between the mid-plane and the exterior surface of a trough, these two distances being identical. The height, thickness and pitch values are determined by Fi<H3/(8×E×(H+P))<Fs, where Fi=25 mm and Fs=35 mm.

Abstract: A tubular element (3) for a drill stem comprising a substantially cylindrical body (12) and two tool joints (4, 5), each tool joint being disposed at one end of the body and provided with a threaded portion (18, 19) which can be joined to a complementary element, at least one of the tool joints having a lifting surface (22) which can cooperate with a lifting tool of the element to connect it into a drill stem, characterized in that the lifting surface has a non-circular cross-section forming an activation zone (24) for a drilling fluid.

Abstract: The invention relates to a rotary drill stem component for exploration of a hydrocarbon well with drilling mud in movement around the component from a bottom of the well towards the surface. The drill can include a central tubular element having an axis of revolution and extended on either side respectively by a first and a second tool joint each respectively and successively including a first cylindrical portion connected to the tubular element, a second tapered portion, a third cylindrical portion with a radius greater than that of the tubular element. The drill can include a threaded end which can connect the component to another component, the component including a first shell provided with one or more functional zones, the first shell being mounted on one of the tool joints in a cohesive and removable manner.

Abstract: A rotary drill stem component for exploration of a hydrocarbon well with drilling mud in movement around the component from a bottom of the well towards the surface includes a central tubular element having an axis of revolution and extended on either side respectively by a first and a second tool joint each respectively and successively including a first cylindrical portion connected to the tubular element, a second tapered portion, a third cylindrical portion with a radius greater than that of the tubular element, and a threaded end which can connect the component to another component, the component including a first shell provided with one or more functional zones, the first shell being mounted on one of the tool joints in a cohesive and removable manner.