A Merlin™ family mechanical connector provided with a thread on substantially matching frustoconical surfaces extending between two sets of nipple seals utilize assembly/disassembly fluids that solidify after the assembly and are brought to liquid state before the disassembly. They include resins or tar-like non-metals and liquid metals solidifying in single phases as well as in multiple phases like for example binary, ternary etc. eutectics. That improves already very good leak resistance of Merlin™ family connectors and benefits good heat transfer between pins and boxes. Thread angle mismatching between box and pin threads can be introduced in order to improve loading. The above modifications can be introduced to traditional connectors featuring torsional load capacities limited to frictional resistance and to connectors designed to transfer high torsional loads.

In a threaded connection for pipe having a two-step thread construction with intermediate shoulder surfaces, compression resistance is further improved. Upon completion of make-up of the pin 2 and box 3, the diameter of a stabbing clearance is 0.15 mm or smaller, where the stabbing clearance is defined between the stab flank of a male thread including an inner thread portion 27 and an outer thread portion 23 and the stab flank of a female thread including an inner thread portion 36 and an outer thread portion 32, thereby causing the stab flanks of the male and female threads to start to be in contact before the angle of rotation θ of the intermediate shoulder surfaces 25 and 34 as appearing in a longitudinal cross section starts to rapidly increase, thus preventing accumulation of damage in the intermediate shoulder surfaces 25 and 34.

A threaded tubular connection includes a tubular female end extending from a main body of a first tubular member, and a tubular male end extending from a main body of a second tubular member, such that the tubular male end includes a first machined inner surface close to the male free end and a second machined inner cylindrical surface above a threaded portion of the male end such that a second inner diameter of the second machined inner cylindrical surface is smaller than a first inner diameter of the first machined inner surface.

A sealing system connecting first and second tubular members includes a first curvilinear sealing surface on the first tubular member and a second curvilinear sealing surface on the second tubular member. Both the first and second curvilinear sealing surfaces are disposed between two sets of threading on the respective first and second tubular members. When the first and second tubular members are in a connected configuration, the first and second curvilinear sealing surfaces contact and interfere to form an annular curvilinear center seal. A relief pocket may be disposed adjacent to the first and/or second curvilinear sealing surfaces to contain excess lubricant between the first and second tubular members.

A two-step threaded connection for steel pipe includes an intermediate seal and intermediate shoulders. A pin 2 has an inner male-threaded section 23 and an outer male-threaded section 26. A box 3 has an inner female-threaded section 33 and an outer female-threaded section 36. The pin 2 has a pin intermediate critical cross section PICCS located near an end of the first male-threaded section 23. The box 3 has a box critical cross section BCCS located near an end of the inner female-threaded section 33 and a box intermediate critical cross section BICCS located near an end of the outer female-threaded section 36. The pin 2 and the box 3 satisfy the following relationships:
PICCSA+BICCSA>BCCSA, and
0.70≤PICCSA/BICCSA≤0.95.

A threaded tubular connection which includes a pin member and a mating box member. The pin member has pin threads with stab flanks and load flanks and thread crests and thread roots which are adapted to be made-up with a mating box member having a complimentary thread structure. The threads of the pin member are intentionally made asymmetric to those of the box.

Tubular coupling assembly with modified buttress thread includes a coupling member to couple two pin connections. The coupling member includes an outer surface and an inner surface opposite the outer surface, which can seal to surfaces of the two pin connections. The inner surface includes a first tapered axial portion extending from a first end of the coupling member towards a center of the coupling member. The inner surface includes a second tapered axial portion extending from a second end of the coupling member towards the center of the coupling member. The coupling member includes a shoulder portion connecting the first tapered axial portion and the second tapered axial portion. Regions of the shoulder portion that connect to the first tapered axial portion and to the second tapered axial portion have respective concave shapes to couple to respective convex shapes on each of the two pin connections.

Implementations described and claimed herein provide systems and methods for increasing accuracy of firing perforating charges in an oil well casing. In one implementation, a body of an orientation device has a first portion and a second portion. An opening extends through a center of the body from a first lateral surface to a second lateral surface, and the opening is configured to receive a perforating gun string. An outer perimeter surface extends about the center of the body from the first lateral surface to the second lateral surface. The outer perimeter surface has a first shape associated with the first portion and a second shape associated with the second portion. The second shape forms a base portion configured to maintain the perforating gun string in an orientation by preventing rotation of the perforating gun string. The orientation corresponds to a predetermined perforating charge direction of the perforating gun string.

An orientable perforating gun assembly includes a gun housing and a charge carrier positioned within an interior space of the gun housing. The charge carrier supports a shaped charge in a fixed rotational orientation relative to the gun housing. The orientable perforating gun assembly further includes an orientation alignment ring rotatably connected to a first end of the gun housing.

An orientable perforating gun assembly may include a gun housing with a charge carrier and shaped charge positioned within an interior space of the gun housing, in fixed orientation relative to the gun housing. An orientation alignment ring may be connected to a first end of the gun housing. The orientation alignment ring and the gun housing may be rotatable relative to each other when the orientation alignment ring is in an unfixed connection state. The gun housing may be in a fixed orientation relative to the orientation alignment ring in a fixed connection state. A locking ring may be connected to the gun housing first end. A method may include orienting the perforating gun housing relative to the orientation alignment ring and other perforating gun assemblies in a string.