A downhole sealant injection system includes a first casing configured to be positioned in a wellbore and a second casing configured to be positioned in the wellbore within the first casing. Cement at least partially fills an annulus between the interior of the first casing and the exterior of the second casing. A first sealant injection tool is configured to be attached to the exterior of the second casing, and is positioned at a downhole location and within an annulus between the interior of the first casing and the exterior of the second casing. The sealant injection tool includes a plurality of nozzles configured to inject sealant into voids within the cement in the annulus between the interior of the first casing and the exterior of the second casing.

A downhole sealant injection system includes a first casing configured to be positioned in a wellbore and a second casing configured to be positioned in the wellbore within the first casing. Cement at least partially fills an annulus between the interior of the first casing and the exterior of the second casing. A first sealant injection tool is configured to be attached to the exterior of the second casing, and is positioned at a downhole location and within an annulus between the interior of the first casing and the exterior of the second casing. The sealant injection tool includes a plurality of nozzles configured to inject sealant into voids within the cement in the annulus between the interior of the first casing and the exterior of the second casing.

A method includes providing an expandable metal slurry downhole in a wellbore. The expandable metal slurry includes granules of an expandable metal material suspended or dispersed in a fluid. Further, the method includes positioning the expandable metal slurry within the wellbore such that the granules of the expandable metal material in the expandable metal slurry are activatable to expand and form a seal within the wellbore.

A method includes providing an expandable metal slurry downhole in a wellbore. The expandable metal slurry includes granules of an expandable metal material suspended or dispersed in a fluid. Further, the method includes positioning the expandable metal slurry within the wellbore such that the granules of the expandable metal material in the expandable metal slurry are activatable to expand and form a seal within the wellbore.

Application of biodegradable oils to additive particles to control dusting. A method of reducing an amount of dust produced during transfer of additive particles comprising: treating at least some of the additive particles with one or more biodegradable oils; storing the additive particles; and transferring the additive particles prior to and after storage, wherein biodegradable oil reduces the amount of dust produced during at least one of the transfers of the additive particles.

Application of biodegradable oils to additive particles to control dusting. A method of reducing an amount of dust produced during transfer of additive particles comprising: treating at least some of the additive particles with one or more biodegradable oils; storing the additive particles; and transferring the additive particles prior to and after storage, wherein biodegradable oil reduces the amount of dust produced during at least one of the transfers of the additive particles.

A system for fluid monitoring in a borehole for extracting hydrocarbons includes a casing to transport hydrocarbons, the casing defining an annulus between the casing and borehole wall. The system further includes a centralizer, coupled to the casing, to center the casing within the borehole. The system further includes a sensor unit, including a radio frequency identification (RFID) interrogator, positioned on the centralizer to monitor one or more fluids, including RFID tags, in the annulus.

A system for fluid monitoring in a borehole for extracting hydrocarbons includes a casing to transport hydrocarbons, the casing defining an annulus between the casing and borehole wall. The system further includes a centralizer, coupled to the casing, to center the casing within the borehole. The system further includes a sensor unit, including a radio frequency identification (RFID) interrogator, positioned on the centralizer to monitor one or more fluids, including RFID tags, in the annulus.

A system that is positionable in a wellbore can include a chain of transceivers that are positionable external to a casing string. Each transceiver in the chain of transceivers can be operable to transmit a wireless signal using a separate frequency guard band that is assigned to that transceiver and to receive wireless signals using another frequency guard band assigned to a prior transceiver in the chain of transceivers.

Methods and compositions for treating a subterranean formation with salt-tolerant cement slurries including treating a salt-containing subterranean formation having sodium salts, potassium salts, magnesium salts, calcium salts, or any combination thereof comprising: providing a salt-tolerant cement slurry comprising: a base fluid, a cementitious material, a pozzolanic material, a salt-tolerant fluid loss additive, a salt additive, and optionally, an elastomer, a weight additive, a fluid loss intensifier, a strengthening agent, a dispersant, or any combination thereof; introducing the salt-tolerant cement slurry into the subterranean formation; and allowing the salt-tolerant cement slurry to set.