Abstract: A device and the relative are described, for the insertion of a new drilling string-element into a drilling-string essentially including a short pipe-shaped body (C) having, at opposite ends thereof, a device suitable for screwing the body onto drill pipes, in which two valves are housed, of which one valve (A) is radial to said short body, interceptable from the outside by means an adaptor and equipped with a suitable safety plug, the other valve (B) being axial with respect to the body.

Abstract: Equipment for intercepting and diverting a liquid circulation flow, consisting of three flow chambers and a series of valves, said chambers, equipped with connection means with arrival or supply lines, communicating with each other, of which only one (I) communicates with both of the other two (II) (III), the communication between said chambers each being obtained by means of at least two valves of which one is a flow-rate valve (Q) and at least one equalizer (E), each equalizer valve (E) being coupled, upstream or downstream thereof, with fixed or adjustable flow-blocking devices (D), the two non-communicating chambers having a valve (V) or a three-way valve in common, or one each, a one-way valve in counterposition, one being open when the other is closed and vice versa, said valve (V) being coupled with a discharge valve (S).

Abstract: A centralizer for an oil well drill casing including at least one strip of ceramic or plastic material applied onto an outer wall of the casing.

Abstract: Method for the centralization of drill casings in a tight borehole, both vertical and deviated, comprising the following operations: Application on the casing section in question, of an adherence strip equipped with one or more housings and rapid adjustable lever closure; Insertion of suitable molds in the housings of which the strip is equipped; Injection into the molds of plastic material characterized by a high mechanical resistance, a high degree of surface adhesion and resistance to abrasion by friction, and also in-place elasticity, higher than the elasticity of the casings; Removal of the adherence strip once the hardening of the plastic material in the shape of the mold, has been completed.

Abstract: A device and the relative procedure are described, for the insertion of a new drilling string-element into a drilling-string essentially consisting of a short pipe-shaped body (C) having, at its ends, means suitable for screwing it onto drill pipes, in which two valves are housed, of which one (A) is radial to said short body, interceptable from the outside by means of an adaptor and equipped with a suitable safety plug, the other (B) axial to said body.

Abstract: Improved method for the drilling of the initial phase of deep water oil wells with an underwater well head consisting in the positioning and cementation of the conductor pipe and anchorage casing by means of a single drilling phase. A tapered hole (with a double diameter) is drilled using a drill string consisting of a motor driven pilot bit and a reaming bit.

Abstract: Process for recovering at least 70% of hollow glass microspheres having an average diameter, according to the ASTM D1214-1989, ranging from 5 to 200 ?m contained in a mixture of drilling mud and cuttings which comprises: a) screening, if necessary, the mixture through one or more 5 to 20 mesh sieves; b) feeding the screened mixture to one or more cyclones and/or hydrocyclones arranged in series, each of which is fed with a volume flow-rate from 1.5 to 10 times higher than the maximum nominal operating value.

Abstract: Method for the centralization of drill casings in a tight borehole, both vertical and deviated, comprising the following operations: Application on the casing section in question, of an adherence strip equipped with one or more housings and rapid adjustable lever closure; Insertion of suitable moulds in the housings of which the strip is equipped; Injection into the moulds of plastic material characterized by a high mechanical resistance, a high degree of surface adhesion and resistance to abrasion by friction, and also in-place elasticity, higher than the elasticity of the casings; Removal of the adherence strip once the hardening of the plastic material in the shape of the mould, has been completed.

Abstract: Process for recovering at least 70% of hollow glass microspheres having an average diameter, according to the ASTM D1214-1989, ranging from 5 to 200 &mgr;m contained in a mixture of drilling mud and cuttings which comprises: a) screening, if necessary, the mixture through one or more 5 to 20 mesh sieves; b) feeding the screened mixture to one or more cyclones and/or hydrocyclones arranged in series, each of which is fed with a volume flow-rate from 1.5 to 10 times higher than the maximum nominal operating value.

Abstract: Improved method for the drilling of the initial phase of deep water oil wells with an underwater well head consisting in the positioning and cementation of the conductor pipe and anchorage casing by means of a single drilling phase. A tapered hole (with a double diameter) is drilled using a drill string consisting of a motor driven pilot bit and a reaming bit.

Abstract: Method for the drilling of oil wells and for the positioning of the appropriate casings, consisting in drilling the well section of interest and, during the drilling, in maintaining a high degree of hole regularity by the use of automatic verticality and/or curvature control equipment. This method allows the positioning of casings with an almost constant clearance with values of +/−1.5 inches for the whole well depth (lean profile).

Abstract: Procedure for evaluating the parameter of actual K.sub.a total friction of a shouldered threaded connection which includes:a) making up the connection applying a general make-up torque and observing the corresponding torque/turn diagram;b) subsequently breaking out the connection observing the corresponding torque/turn diagram;c) calculating the actual K.sub.a of the connection with an appropriate equation.