Abstract: An apparatus comprises perforating guns, bypass, and isolator mechanism. The first gun fires upon receipt of a first pressure signal delivered from a first axial side of the first gun. The second perforating gun is mounted on a second axial side of the first perforating gun, and fires upon receipt of a second pressure signal delivered from the first axial side of the first perforating gun. The bypass extends from the first axial side of the first gun to the second gun for communicating the second pressure signal to the second gun. The isolator mechanism is configurable between a first configuration in which the bypass is isolated from receiving a pressure signal to the second perforating gun, and a second configuration in which the bypass is permitted to receive a pressure signal. The isolator mechanism is reconfigurable from the first to the second configuration after the first gun has fired.

Abstract: Some examples of the present disclosure relate to a method for washing an annulus that at least partially surrounds a casing in a well. The method comprises locating a tool inside a wellbore casing, and flowing a washing fluid from an injection aperture on the tool and into the annulus via a first casing aperture in the casing. An inflow region of the casing is created having a reduced pressure relative to the annulus, and the method involves flowing the washing fluid from the annulus and into the inflow region of the casing through a second casing aperture in the casing.

Abstract: An apparatus comprises perforating guns, bypass, and isolator mechanism. The first gun fires upon receipt of a first pressure signal delivered from a first axial side of the first gun. The second perforating gun is mounted on a second axial side of the first perforating gun, and fires upon receipt of a second pressure signal delivered from the first axial side of the first perforating gun. The bypass extends from the first axial side of the first gun to the second gun for communicating the second pressure signal to the second gun. The isolator mechanism is configurable between a first configuration in which the bypass is isolated from receiving a pressure signal to the second perforating gun, and a second configuration in which the bypass is permitted to receive a pressure signal. The isolator mechanism is reconfigurable from the first to the second configuration after the first gun has fired.

Abstract: Some examples of the present disclosure relate to a method for washing an annulus that at least partially surrounds a casing in a well. The method comprises locating a tool inside a wellbore casing, and flowing a washing fluid from an injection aperture on the tool and into the annulus via a first casing aperture in the casing. An inflow region of the casing is created having a reduced pressure relative to the annulus, and the method involves flowing the washing fluid from the annulus and into the inflow region of the casing through a second casing aperture in the casing.