Provided herein are compositions and methods for the controlled delivery of acid to a subterranean formation.

A resource exploration and recovery system includes a first system and a second system extending into a wellbore. The second system includes a completion having a casing defining a wellbore internal diameter. A chemical injection tubing extends from the first system into the completion. The chemical injection tubing includes a terminal end portion. A chemical introduction system is arranged at the first system and is fluidically connected to the chemical injection tubing. The chemical introduction system is operable to deliver a chemical into the chemical injection tubing. A chemical injector assembly is mounted to the terminal end portion. The chemical injection system includes an anchor and a chemical injector valve.

A resource exploration and recovery system includes a first system and a second system extending into a wellbore. The second system includes a completion having a casing defining a wellbore internal diameter. A chemical injection tubing extends from the first system into the completion. The chemical injection tubing includes a terminal end portion. A chemical introduction system is arranged at the first system and is fluidically connected to the chemical injection tubing. The chemical introduction system is operable to deliver a chemical into the chemical injection tubing. A chemical injector assembly is mounted to the terminal end portion. The chemical injection system includes an anchor and a chemical injector valve.

Methods and treatment fluids for removing mixed scale. A treatment fluid is introduced into a wellbore comprising a mixed scale of interspersed calcium carbonate and calcium sulfate. The treatment fluid comprises: phosphonomethyliminodiacetic acid, glycine-N,N-bis(methylene phosphonic acid), or a combination thereof; and an aqueous base fluid. The treatment fluid has a pH in a range between about 6 to about 8. The method further comprises contacting the mixed scale with the treatment fluid.

Methods and treatment fluids for removing mixed scale. A treatment fluid is introduced into a wellbore comprising a mixed scale of interspersed calcium carbonate and calcium sulfate. The treatment fluid comprises: phosphonomethyliminodiacetic acid, glycine-N,N-bis(methylene phosphonic acid), or a combination thereof; and an aqueous base fluid. The treatment fluid has a pH in a range between about 6 to about 8. The method further comprises contacting the mixed scale with the treatment fluid.

The present invention addresses to a method of removing scale from the DHSV of the oil production string aiming at maintaining the production of the wells and thus avoiding the loss of production. First, a neutralizing solution is placed in the service line, before pumping the scale removing solution through the string to act on the DHSV. Next, the acid is pumped into the production string to react with the calcium carbonate scale. After the time for the dissolution of the scale inside the DHSV, the well is opened for production by the service line. The spent acid is mixed with the neutralizing solution inside the service line, reducing its corrosiveness in relation to the service line, contributing to its preservation.

The disclosure describes hydrocarbon flowline corrosion inhibitor overpressure protection. Such a protection system includes a fluid flow pathway fluidically coupled to a corrosion inhibitor injection pump that injections corrosion inhibitor into a hydrocarbon carrying flowline. When the injection pump pressure exceeds a threshold flow pressure, the corrosion inhibitor is flowed through a first branch of the fluid flow pathway to relieve the excess pressure. The first branch is fluidically isolated from a second branch. When a rupture disc in the first branch fails, then the corrosion inhibitor is diverted to flow through the second branch and the first branch is isolated from the corrosion inhibitor flow.

The disclosure describes hydrocarbon flowline corrosion inhibitor overpressure protection. Such a protection system includes a fluid flow pathway fluidically coupled to a corrosion inhibitor injection pump that injections corrosion inhibitor into a hydrocarbon carrying flowline. When the injection pump pressure exceeds a threshold flow pressure, the corrosion inhibitor is flowed through a first branch of the fluid flow pathway to relieve the excess pressure. The first branch is fluidically isolated from a second branch. When a rupture disc in the first branch fails, then the corrosion inhibitor is diverted to flow through the second branch and the first branch is isolated from the corrosion inhibitor flow.

A variety of methods, systems, and compositions are disclosed, including, in one embodiment, method of scale inhibition including: introducing a treatment fluid comprising a brine, a scale inhibitor in neutralized form, and a thermally activated acid precursor through a wellbore and into a producing formation; wherein the thermally activated acid precursor is heated to release an acid that enhances miscibility of the scale inhibitor in the brine.

A variety of methods, systems, and compositions are disclosed, including, in one embodiment, method of scale inhibition including: introducing a treatment fluid comprising a brine, a scale inhibitor in neutralized form, and a thermally activated acid precursor through a wellbore and into a producing formation; wherein the thermally activated acid precursor is heated to release an acid that enhances miscibility of the scale inhibitor in the brine.