Well treatment compositions comprise water, a lipophilic anionic surfactant, a hydrophilic non-ionic surfactant, a second non-ionic surfactant, a water-solubilizing solvent, a water-immiscible solvent and a lipophilic non-ionic surfactant. Optionally, a second solvent may be incorporated. When added to spacer fluids, chemical washes or both, the compositions promote the removal of non-aqueous drilling fluids from casing surfaces. Additionally, the treated casing surfaces are water wet, thereby promoting optimal bonding to cement.

Well treatment compositions comprise water, a lipophilic anionic surfactant, a hydrophilic non-ionic surfactant, a second non-ionic surfactant, a water-solubilizing solvent, a water-immiscible solvent and a lipophilic non-ionic surfactant. Optionally, a second solvent may be incorporated. When added to spacer fluids, chemical washes or both, the compositions promote the removal of non-aqueous drilling fluids from casing surfaces. Additionally, the treated casing surfaces are water wet, thereby promoting optimal bonding to cement.

A method includes injecting an aqueous-based injection fluid into a wellbore at a first temperature, where the aqueous-based injection fluid includes phase-changing nanodroplets having a liquid core and a shell. The method also includes exposing the phase-changing nanodroplets to a second temperature in the wellbore that is greater than or equal to a boiling point of the liquid core to change a liquid in the liquid core to a vapor phase and expand the phase-changing nanodroplets, thus removing debris from the wellbore and surrounding area.

A method includes injecting an aqueous-based injection fluid into a wellbore at a first temperature, where the aqueous-based injection fluid includes phase-changing nanodroplets having a liquid core and a shell. The method also includes exposing the phase-changing nanodroplets to a second temperature in the wellbore that is greater than or equal to a boiling point of the liquid core to change a liquid in the liquid core to a vapor phase and expand the phase-changing nanodroplets, thus removing debris from the wellbore and surrounding area.

A method for displaying performance of a wellbore drilling operation including wellbore cleaning includes defining drilling parameters for the drilling operation. The method includes defining a visualization tool including a boundary defined by the drilling parameters, where the boundary depicts an optimal rate of penetration (ROP). The method includes displaying the visualization tool with the optimal ROP, where the optimal ROP defines a maximum ROP for optimal wellbore cleaning based on the drilling parameters. The method includes displaying an actual rate of penetration (ROP) with respect to the optimal ROP on the visualization tool. The method further includes adjusting the actual ROP to match the optimal ROP.

A tool (1) for cementing an annulus in a subsea oil or gas well, and methods for using the tool are provided. The tool includes a safety module (2) providing fluid communication between an umbilical and a perforation and circulation module (4) mounted below it. The safety module (2) includes a mechanical lock for connection to a well head. The perforation and circulation module includes upper and lower seals (6, 8) for sealing to the inner surface of a casing; an upper perforating device (14) mounted between the seals; a lower perforating device (16) mounted below the lower seal (8); and supply (S) and return (R) fluid flow paths for circulating fluid from the safety module (2). A diversion means (20) is provided in the supply fluid flow path, operable to redirect fluid supplied to the supply fluid flow path to a space defined between the upper and lower seals (6, 8).

A method includes treating a reservoir with a damaged near wellbore region (NWR), including introducing a liquid foam treatment into a wellbore proximate to the damaged NWR, where the liquid foam treatment has a solution medium and nanobubbles, transmitting an acoustic wave towards the damaged NWR such that the nanobubbles collapse, causing fluid flow pathways to form for hydrocarbon production.

A system includes a solution generation tool for generating a liquid foam treatment, where the liquid foam treatment has a solution medium and nanobubbles, where the nanobubbles migrate along a concentration gradient, and an acoustic signal generator transmits an acoustic signal. The system also includes a downhole tool signally coupled to the acoustic signal generator fluidly coupled to the solution generation tool, and the downhole tool transmits an acoustic wave into an NWR and introduces the liquid foam treatment into the wellbore proximate to the NWR.

A method includes treating a reservoir with a damaged near wellbore region (NWR), including introducing a liquid foam treatment into a wellbore proximate to the damaged NWR, where the liquid foam treatment has a solution medium and nanobubbles, transmitting an acoustic wave towards the damaged NWR such that the nanobubbles collapse, causing fluid flow pathways to form for hydrocarbon production.

A system includes a solution generation tool for generating a liquid foam treatment, where the liquid foam treatment has a solution medium and nanobubbles, where the nanobubbles migrate along a concentration gradient, and an acoustic signal generator transmits an acoustic signal. The system also includes a downhole tool signally coupled to the acoustic signal generator fluidly coupled to the solution generation tool, and the downhole tool transmits an acoustic wave into an NWR and introduces the liquid foam treatment into the wellbore proximate to the NWR.

A method for clearing an obstruction in a wellbore may include opening a first choke that is in fluid communication with the wellbore. This may create a first pressure in the wellbore. The first choke may then be closed. If the choke is adjustable, the choke size may be adjusted to a second size and opened. If the choke is fixed, a second choke of a different size is then opened. When the second choke is opened, a second pressure may be created in the wellbore that is different from the first pressure. The second choke may then be closed. For an adjustable choke, the size is changed to either the first size or a third size. For a fixed choke, either the first choke or a third choke that has a different size may be opened. These steps may be repeated until the obstruction in the wellbore is cleared.

A method for clearing an obstruction in a wellbore may include opening a first choke that is in fluid communication with the wellbore. This may create a first pressure in the wellbore. The first choke may then be closed. If the choke is adjustable, the choke size may be adjusted to a second size and opened. If the choke is fixed, a second choke of a different size is then opened. When the second choke is opened, a second pressure may be created in the wellbore that is different from the first pressure. The second choke may then be closed. For an adjustable choke, the size is changed to either the first size or a third size. For a fixed choke, either the first choke or a third choke that has a different size may be opened. These steps may be repeated until the obstruction in the wellbore is cleared.