A test apparatus can measuring particle plugging of a simulated fracture. The test apparatus can include a first test component having a first surface and a second test component having a second surface. The second test component can be positionable relative to the first test component to create a simulated fracture between the first surface and the second surface. The test apparatus can include a visualization area of at least one of the first test component or the second test component can be positioned between a fluid inlet and a fluid outlet along at least a portion of the simulated fracture.

A method for plugging a lost-circulation zone in a subsurface formation includes introducing a drillstem including a drilling stabilizer into a wellbore during drilling operations, the drilling stabilizer including at least stabilizer blades and a pressure sensor. Each stabilizer blade includes at least an inner chamber, a light source, and a window. The method further includes injecting a lost-circulation fluid, including a plurality of lost-circulation particles, into the wellbore. Each lost-circulation particle includes a lost-circulation additive encapsulated by a photo-sensitive coating. The method further includes measuring a pressure differential with the pressure sensor and providing a pressure signal to the light source of each stabilizer blade, thereby actuating the light source to produce a light beam, which allows the light beam to contact the photo-sensitive coatings of the lost-circulation particles to release the lost-circulation additives. The method further includes allowing the lost-circulation fluid to plug the lost-circulation zone.

An apparatus includes a tool body having a bore that is aligned with a lengthwise axis and a rotating assembly coupled to the tool body. The rotating assembly includes a turbine wheel that is disposed adjacent to an inner surface of the wall and exposed to the bore. The rotating assembly includes an impeller that is disposed adjacent to an outer surface of the wall in a position corresponding to the turbine wheel. Each of the turbine wheel and impeller has a respective axis of rotation that is transverse to the lengthwise axis. The rotating assembly includes a link rod that couples the turbine wheel to the impeller and is used to transfer mechanical energy generated by the turbine wheel to the impeller. The apparatus is operable by fluid flow through a drill string to increase pressure in a wellbore annulus and enhance transportation of formation cuttings up the annulus.

An apparatus includes a tool body having a bore that is aligned with a lengthwise axis and a rotating assembly coupled to the tool body. The rotating assembly includes a turbine wheel that is disposed adjacent to an inner surface of the wall and exposed to the bore. The rotating assembly includes an impeller that is disposed adjacent to an outer surface of the wall in a position corresponding to the turbine wheel. Each of the turbine wheel and impeller has a respective axis of rotation that is transverse to the lengthwise axis. The rotating assembly includes a link rod that couples the turbine wheel to the impeller and is used to transfer mechanical energy generated by the turbine wheel to the impeller. The apparatus is operable by fluid flow through a drill string to increase pressure in a wellbore annulus and enhance transportation of formation cuttings up the annulus.

What is provided is a method and apparatus which can be detachably connected to an annular blowout preventer thereby separating the drilling fluid or mud into upper and lower sections and allowing the fluid to be displaced in two stages, such as while the drill string is being rotated and/or reciprocated. In one embodiment the sleeve can be rotatably and sealably connected to a mandrel. The swivel can be incorporated into a drill or well string and enabling string sections both above and below the sleeve to be rotated in relation to the sleeve. In one embodiment the drill or well string does not move in a longitudinal direction relative to the swivel. In one embodiment, the drill or well string does move longitudinally relative to the sleeve of the swivel.

What is provided is a method and apparatus which can be detachably connected to an annular blowout preventer thereby separating the drilling fluid or mud into upper and lower sections and allowing the fluid to be displaced in two stages, such as while the drill string is being rotated and/or reciprocated. In one embodiment the sleeve can be rotatably and sealably connected to a mandrel. The swivel can be incorporated into a drill or well string and enabling string sections both above and below the sleeve to be rotated in relation to the sleeve. In one embodiment the drill or well string does not move in a longitudinal direction relative to the swivel. In one embodiment, the drill or well string does move longitudinally relative to the sleeve of the swivel.

Pumpable process-fluid compositions comprise polyacrylamide, a non-metallic crosslinker and a pH-adjustment material. Such compositions have utility in the context of controlling lost circulation in subterranean wells. Upon entering at least one lost circulation zone, the compositions crosslink, thereby forming a barrier that minimizes or stops fluid flow from the wellbore into the lost circulation zone.

A measurement head for making X-ray measurements on drilling fluid includes an inner pipe (30) having a outlet (32) and an outer pipe (34) around the inner pipe. Drilling fluid is pumped through the outlet refreshing the fluid at the outlet. The pump is then stopped. A height sensor (42) is then used to measuring the height of a meniscus of drilling fluid at the outlet (32). An X-ray head (50) including an X-ray source (52) and an X-ray detector (54) is then moved into a reproducible position above the meniscus of fluid above the outlet. The height sensor (42) may be fixed to a movable cover (40), to the X-ray head (50) or to some other part of the measurement head.

A method for reducing lost circulation in a subterranean formation. The method includes providing a treatment fluid comprising a base fluid and a lost circulation material comprising red mud. The treatment fluid is introduced into a wellbore within the subterranean formation such that at least a portion of the red mud bridges openings in the subterranean formation to reduce loss of fluid circulation into the subterranean formation.

What is provided is a method and apparatus which can be detachably connected to an annular blowout preventer thereby separating the drilling fluid or mud into upper and lower sections and allowing the fluid to be displaced in two stages, such as while the drill string is being rotated and/or reciprocated. In one embodiment the sleeve can be rotatably and sealably connected to a mandrel. The swivel can be incorporated into a drill or well string and enabling string sections both above and below the sleeve to be rotated in relation to the sleeve. In one embodiment the drill or well string does not move in a longitudinal direction relative to the swivel. In one embodiment, the drill or well string does move longitudinally relative to the sleeve of the swivel.