Valve systems for inserting into casings used in downhole environments are provided. The valve system includes a mandrel, a check valve assembly, and a setting system. The setting system includes a sealing element, a pair of wedges, and a pair of slips, each located on an outer surface of the mandrel. The wedges are separated from each other by the sealing element. Each wedge includes an inner surface configured to slide along the outer surface of the mandrel and an angled surface having a first set of ratchet teeth. The slips are separated from each other by the pair of wedges. Each slip includes an inner surface having a second set of ratchet teeth configured to engage the first set of ratchet teeth. Also, each slip includes an outer surface having gripping elements configured to grip an inner surface of the casing.

In view of the problems of complex downhole conditions, low control precision of bottomhole pressure, low one-time success rate of well-killing and the like during a high-temperature and high-pressure deep well-killing operation, a well-killing operation wellbore flowing model is established according to measured data during throttled well-killing. The fluid distribution and flowing states in a wellbore annulus are analyzed in real time, and during a measured standpipe pressure deviation design, a pressure control value is calculated accurately in consideration of the effects of a pressure wave propagation speed and a back pressure application delay, and a throttle valve is automatically adjusted and automatically controlled to actuate.

In view of the problems of complex downhole conditions, low control precision of bottomhole pressure, low one-time success rate of well-killing and the like during a high-temperature and high-pressure deep well-killing operation, a well-killing operation wellbore flowing model is established according to measured data during throttled well-killing. The fluid distribution and flowing states in a wellbore annulus are analyzed in real time, and during a measured standpipe pressure deviation design, a pressure control value is calculated accurately in consideration of the effects of a pressure wave propagation speed and a back pressure application delay, and a throttle valve is automatically adjusted and automatically controlled to actuate.

A downhole tool configured to vary the amount of pressurized fluid delivered to other tools incorporated into a bottom hole assembly, such as a mud motor. The tool comprises an inner element installed within an outer sleeve. The inner element is configured to move between three different positions relative to the outer sleeve. In a first position, pressurized fluid is diverted away from downstream tools within the bottom hole assembly. In a second and third position, pressurized fluid is directed towards downstream tools. Movement of the tool between the different positions is caused by varying external forces applied to the tool.

A modular fluid-carrying manifold apparatus is provided for use in hydraulic fracturing blenders and other devices. A manifold can include one or more interchangeable sections. Each section may have a flat front face with ports cut into the front face. Components such as valves and hammer unions are directly removably connected to the ports via bolts. This eliminates the need for welded-on piping. Removable, wear-resistant inserts can be located in the ports. The removable components may be considered consumable and replaced when worn out.

A modular fluid-carrying manifold apparatus is provided for use in hydraulic fracturing blenders and other devices. A manifold can include one or more interchangeable sections. Each section may have a flat front face with ports cut into the front face. Components such as valves and hammer unions are directly removably connected to the ports via bolts. This eliminates the need for welded-on piping. Removable, wear-resistant inserts can be located in the ports. The removable components may be considered consumable and replaced when worn out.

A wellbore isolation assembly includes an outer component and an inner component. The outer component is disposed at a first location in a wellbore. The inner component is disposed at a second location in the wellbore. The inner component is moved from the second location into engagement with the outer component at the first location to form a barrier within the wellbore. When deployed in the wellbore, the barrier inhibits passage of fluids. The wellbore isolation assembly is then retrieved from the wellbore.

A well system includes a tubular string comprising a plurality of tubular segments and positioned in a wellbore drilled into a subterranean zone, and a landing sub connected to a bottom end of one of the plurality of tubular segments. The landing sub includes a landing sub central bore and a landing sub locking profile on an inner surface of the landing sub central bore. The well system also includes a valve assembly configured to be pumped down the tubular string by fluid flowing in a downhole direction through the tubular string and to land within the landing sub central bore. The valve assembly includes a main body with a valve central bore and a flapper configured to pivot between an open position and a closed position. In the closed positon the flapper seals against a flapper seat and blocks fluid from flowing in an uphole direction through the valve central bore. The valve assembly also includes a rupture disc positioned in the valve central bore and configured to rupture in response to an application of a predetermined fluid pressure and configured to block fluid from flowing through the valve central bore when in an unruptured state. The valve assembly also includes one or more valve body setting dogs positioned on an outer surface of the main body and configured to lock into the landing sub locking profile and thereby limit axial movement of the main body within the landing sub.

A drilling mud screen comprising: a body having a first end and a second end and a centerline, wherein the first end and/or the second end of the body has a means to engage a drilling mud screen puller/installer tool; a drilling mud inlet at the first end of the body; a filter having a first end, a second end, and openings, wherein the filter is fluidly connected to the second end of the body via a first connection and/or an optional first end retaining ring; a drilling mud outlet at the openings of the filter; and a second end cap fluidly connected at the second end of the filter via a second connection, wherein the filter has an optional retaining ring disposed between the first connection and the second connection is disclosed.

A drilling mud screen comprising: a body having a first end and a second end and a centerline, wherein the first end and/or the second end of the body has a means to engage a drilling mud screen puller/installer tool; a drilling mud inlet at the first end of the body; a filter having a first end, a second end, and openings, wherein the filter is fluidly connected to the second end of the body via a first connection and/or an optional first end retaining ring; a drilling mud outlet at the openings of the filter; and a second end cap fluidly connected at the second end of the filter via a second connection, wherein the filter has an optional retaining ring disposed between the first connection and the second connection is disclosed.