A sub, downhole tool, and method for manufacturing thereof, are disclosed. The sub may include one or more flow channels, each of which may be defined in part by a longitudinal groove formed along an exterior of a collar. One or more flow channel cover may be connected to the collar. The longitudinal grooves position the flow channels further outward to provide more volume within the collar that may be used for housing one or more devices. Upper and lower blind bores are fluidly coupled to the longitudinal grooves by angled through bores to complete the flow channels. A medial bore, which may be fluidly isolated from the flow channels, may be provided to house a device, such as an instrument, detector, or circuitry.

A system for recirculating a portion of a liquid fraction of multiphase production fluid to a pump for enhanced functionality thereof. The system includes a splitter assembly that obtains the multiphase production fluid from the pump. The splitter assembly utilizes multiple internal chambers to separate gas and liquid fractions of the fluid. A portion of the liquid fraction may then be recirculated back to the pump as indicated whereas the remainder of the liquid fraction may be recombined with the gas fraction for production.

A system for recirculating a portion of a liquid fraction of multiphase production fluid to a pump for enhanced functionality thereof. The system includes a splitter assembly that obtains the multiphase production fluid from the pump. The splitter assembly utilizes multiple internal chambers to separate gas and liquid fractions of the fluid. A portion of the liquid fraction may then be recirculated back to the pump as indicated whereas the remainder of the liquid fraction may be recombined with the gas fraction for production.

The present invention relates to methods of treating subterranean formations. In various embodiments, the present invention provides a method of treating a subterranean formation including placing a first aqueous composition and a second aqueous composition in a subterranean formation. The placing includes injecting the first aqueous composition through a tubular passage in a wellbore. The placing also includes injecting the second aqueous composition through an annular passage in the wellbore.

A method for modifying a return fluid in a wellbore comprising disposing at least one valve along a drill pipe section of a drill string in the wellbore. At least one parameter of interest is determined at at least one location along the wellbore. At least one valve is controllably actuated to discharge at least a portion of at least one fluid from inside the drill string to an annulus in the wellbore to modify a local property of the return fluid in the annulus based at least in part on the measured parameter of interest.

A method for modifying a return fluid in a wellbore comprising disposing at least one valve along a drill pipe section of a drill string in the wellbore. At least one parameter of interest is determined at at least one location along the wellbore. At least one valve is controllably actuated to discharge at least a portion of at least one fluid from inside the drill string to an annulus in the wellbore to modify a local property of the return fluid in the annulus based at least in part on the measured parameter of interest.

A method and a downhole apparatus for clearing a wellbore are disclosed. The method locates a mill in the wellbore about the obstructions, introduces a driving fluid flow along a driving flow path from surface to the mill, and introduces a circulation fluid flow along a circulation flow path from surface into a wellbore annulus at a location in the wellbore above the mill. Then the mill is driven by the introduced driving fluid flow to mill the obstructions; and milled obstructions are circulated to the surface via the wellbore annulus using the introduced circulation fluid and gas flow. At least a portion of the circulation flow path is within the driving flow path.

An improved seal disposed at an interface of a main body of an inner drilling riser tie-back connector (ITBC) and a subsea wellhead is provided. The seal comprises a main body portion formed of a pair of opposed inwardly projecting fingers having a saw-cut profile at their ends and an outwardly projecting lever arm disposed adjacent to and at an outward angle to one of the opposed inwardly projecting fingers. Under loading the outwardly projecting lever arm imparts a bending moment to the seal, which enhances the seal created between the ITBC and the subsea wellhead and reduces the torque required to disengage the internal tie-back connector

The present invention refers to a method of drilling a marine wellbore with fluid reverse circulation without using drilling riser tubulars. In reverse circulation drilling, the fluid return with gravels occurs inside the drill string (17) and the injection of clean fluid is done through the annular of the well, so that, having a rotating head over the BOP (19), or inside it, the use of riser tubulars as a flow line for the fluid return with gravels is disposed, using instead the drill string (17).

For the kill and choke lines, as well as for fluid injection, rigid or flexible lines can be used, eliminating the need to use drilling risers, thus releasing large load capacity and space on the probe. The method of this invention also eliminates the need for large volumes of fluid to fill entire riser tubulars. The entire operation can be done without the need for subsea pumps or concentric columns. Additionally, the invention makes the operation of lowering the drilling riser tubulars unnecessary, which lasts for days and has a high cost. Finally, for dual activity probes, the arrangement allows the use of the two towers even after connecting the BOP (19), something that is not possible with the use of drilling riser tubulars. Therefore, operations such as mounting and lowering the casing in the water depth can be carried out in parallel with the drilling of the phase, allowing a significant additional gain of time.

A set of manifold string members usable to selectively control separate flowing fluid streams of varying velocities for operations of well construction, injection or production of fluid mixtures of liquids, gases and/or solids, that can be injected into, or taken from, one or more proximal regions of a subterranean passageway, underground cavern, hydrocarbon or geothermal reservoir. Fluid communicated through a manifold string radial passageway of a manifold crossover, between conduit strings and at least one other conduit, can be controlled with at least one flow controlling member, communicating with a passageway member from an innermost, concentric, and/or annular passageway. Fluid communication can be selectively controlled for various configurations of one or more substantially hydrocarbon and/or substantially water wells, below a single main bore and wellhead.