An example CO.sub.2 monitoring systems is configured for monitoring levels of CO.sub.2 in a wellbore. A CO.sub.2 monitoring system may include one or more laser monitoring tools. A laser monitoring tool may include an optical element to output a laser beam, a detector to receive the laser beam, a first chamber housing the optical element and detector, and a second chamber including an inlet and an outlet receive and release, respectively, wellbore fluid. The first chamber may be in fluid connection with second chamber via a gas permeable membrane. Gas may permeate from second chamber into first chamber. Gas in the first chamber is subjected to a laser beam. Absorption of light by the gas is measured, and content of gas is determined based at least in part on the amount of light absorption by the gas.

A method of operating an actuator in mud having debris and lost circulation material is described. The method includes closing a servo valve positioned within a valve housing. The valve housing has a plurality of fluid vents positioned downstream of the servo valve and a plurality of debris vents positioned upstream of the servo valve. Dimensions of the plurality of fluid vents are less than dimensions of the plurality of debris vents. Closing of the servo valve creates a first fluid path such that fluid flows from a mud pump at a surface into the plurality of debris vents and out of the plurality of fluid vents shielding the servo valve from debris and lost circulation material.

A tool includes an internal assembly configured to be positioned at least partially within a body. The tool also includes a collet configured to be positioned at least partially within the body and axially-adjacent to the internal assembly. The collet includes a plurality of fingers that are circumferentially-offset from one another. At least one of the fingers includes a protrusion that extends adially-outward and is configured to be positioned at least partially within a recess formed in an inner surface of the body to secure the collet in place with respect to the body. The tool also includes a collet pin configured to be positioned at least partially within the body, axially-adjacent to the internal assembly, and at least partially within the collet. The collet pin is configured to contact the internal assembly to secure the internal assembly in place within the body.

A drilling turbine (1) comprises a housing (2) in which a drive shaft (6) is rotatably mounted, and a turbine impeller (3) designed to set the drive shaft (6) in rotation. The drive shaft (6) is connectable to a drilling tool (4, 5). The housing has at least one drive line (9, 12) with at least one drive mouth (19), through which a drive fluid can be directed onto the turbine impeller (3). The turbine impeller (3) is connected directly to the drive shaft (6) such that, during operation, the turbine impeller (3), the drive shaft (6) and the drilling tool (4, 5) rotate at the same rotational speed. The housing (2) has a diameter of about 2.5 to about 15 cm and/or a length of about 3 cm to about 15 cm. A method for directional drilling uses a drilling turbine of this type.

A rotating cutter apparatus including a housing having a housing interior surface defining a housing bore, a shaft extending through the housing bore such that an annular space is provided between the housing interior surface and the shaft, and at least one cutter carried on the shaft. The shaft is rotatable relative to the housing about a shaft axis. The at least one cutter extends radially toward the housing interior surface and is rotatable relative to the housing about the shaft axis. A method for reducing a size of solid objects contained in a fluid, including providing a rotating cutter apparatus, introducing the fluid containing the solid objects into the rotating cutter apparatus, and rotating a shaft and at least one cutter in order to reduce the size of the solid objects while passing the fluid through the rotating cutter apparatus.

A sand separator for capturing solid debris from oil and gas wells includes a spherical, high-pressure vessel adapted to couple downstream of a wellhead. Fluid entering the separator follows a helical path around a vertical separator axis, slowing and separating into water, gas, oil and solid debris, the latter sinking to the bottom. A conical, downwardly opening flue descends from an exit port at the top and terminates in a horizontal, coaxial perimeter. A scalloped, annular collar inside the flue perimeter creates a low barrier to fluid flow into the flue. As fluid constituents circulate toward the flue, they recombine free of sand and rock debris, pass under the flue perimeter and across the collar, slowing further and becoming substantially laminar A fluid dome rises inside the flue with a gas layer above other fluid constituents, permitting the gas to exit the separator through the exit port.

An air/water separator including a first hollow member configured to receive a flow including an air and water mixture and a second hollow member configured to receive the flow from the first hollow member. An exit of the first hollow member extends into an opening of the second hollow member such that the exit of the first hollow member axially overlaps the opening of the second hollow member, thereby creating a first flow path from the interior of the first hollow member to the outside of the second hollow member including two turns about the exit of the first hollow member and opening of the second hollow member, and a second flow path from the first hollow member through the second hollow member.

In accordance with embodiments of the present disclosure, a debris separator device for use with a casing system may include an impeller having a plurality of blades to generate a vortex of mud in the section of the casing system when the casing system is lowered into a wellbore. The device may also include a baffle disposed in the section of the casing system, the baffle having an annular cup shape that forms an outer circumferential pocket to capture debris from the vortex of mud. The impeller and baffle may enable the debris separator device to separate debris and other debris from a flow of mud through the casing system so that the debris does not clog a float collar of the system. The disclosed debris separator device may be flushable so that the device does not become clogged with debris and can thereby maintain auto-fill through the casing system.

A downhole assembly can include screens along a length of a tubular member. Screens covering differing portions of a cross-sectional area of the tubular and less than an entirety of the cross-sectional area can be offset from one another along a length of the tubular. Fluid flowing through an area not covered by a first screen can encounter an area covered by an offset screen. If the offset screen is blocked with accumulated debris, fluid may pass the offset screen by passing through an area not covered by the offset screen.

Drilling fluid compositions include invert emulsion fluids having an oleaginous phase, an aqueous phase, and an emulsifier composition that includes an ethoxylated alcohol compound and a polyaminated fatty acid compound. The ethoxylated alcohol compound has the formula R.sup.1—(OCH.sub.2CH.sub.2).sub.n—OH, where R.sup.1 is a hydrocarbyl group having from 8 to 22 carbon atoms and n is from 1 to 8. The ethoxylated alcohol compound has a Hydrophilic-Lipophilic Balance (HLB) of less than or equal to 6. The polyaminated fatty acid compound has the formula R.sup.2—CO—NH—CH.sub.2—CH.sub.2—N(COR.sup.2)—CH.sub.2—CH.sub.2—NH—CO—R.sup.3, where R.sup.2 is a hydrocarbyl group having from 1 to 20 carbon atoms and R.sup.3 is a hydrocarbyl group having from 1 to 10 carbon atoms or an alkylene carboxylate group having formula —R.sup.4—COOH, where R.sup.4 is a saturated or unsaturated hydrocarbylene having from 1 to 10 carbon atoms. Methods of drilling wells include operating a drill in a wellbore in the presence of drilling fluid compositions.