Abstract: A treatment tool can include a housing with longitudinal passages, a valve that controls flow between sections of one passage, another valve that controls flow between the one passage and a section of another passage, and a locking device that prevents the first valve from being transitioned to an open configuration from a closed configuration. A method can include flowing a fluid through a passage of a service string and into an annulus about a screen, the fluid entering the screen and flowing to another annulus via another passage of the service string, then installing a plug in the first passage, thereby preventing flow through the first passage to the annulus about the screen, and creating at least one pressure differential across the plug, thereby preventing flow from an interior of the screen to the other annulus and permitting flow from the first passage to the screen interior.

Abstract: A positioning tool can include a mandrel and an engagement device reciprocably disposed on the mandrel. The engagement device can include at least one engagement member and at least one landing dog. The mandrel can displace relative to the engagement device in response to engagement between the engagement member and at least one internal profile in an outer tubular string, and the landing dog can extend outward in response to displacement of the mandrel in a selected longitudinal direction relative to the engagement device. A system for use in a well can include a tubular string and a positioning tool reciprocably disposed in the tubular string. The positioning tool can include a landing dog that extends outward from a retracted position to engage one or more internal profiles of the tubular string, in response to a pattern of reciprocation of the positioning tool in the tubular string.

Abstract: A treatment tool can include a housing with longitudinal passages, a valve that controls flow between sections of one passage, another valve that controls flow between the one passage and a section of another passage, and a locking device that prevents the first valve from being transitioned to an open configuration from a closed configuration. A method can include flowing a fluid through a passage of a service string and into an annulus about a screen, the fluid entering the screen and flowing to another annulus via another passage of the service string, then installing a plug in the first passage, thereby preventing flow through the first passage to the annulus about the screen, and creating at least one pressure differential across the plug, thereby preventing flow from an interior of the screen to the other annulus and permitting flow from the first passage to the screen interior.

Abstract: A system can include a tubular string having at least two internal profiles, and a valve assembly reciprocably disposed in the tubular string. The valve assembly is actuated to a closed configuration in response to displacement of the valve assembly through one internal profile, and the valve assembly is actuated to an open configuration in response to displacement of the valve assembly through another internal profile. A method of gravel packing a well can include displacing a service string in opposite longitudinal directions within a completion assembly, the service string including a valve assembly that selectively restricts flow through a longitudinal flow passage of the service string, opening the valve assembly as the valve assembly displaces in one longitudinal direction, and closing the valve assembly as the valve assembly displaces in the opposite longitudinal direction.

Abstract: A valve assembly can include a generally tubular housing, a mandrel reciprocably disposed in the housing and operative to displace a valve closure in response to relative displacement between the mandrel and the housing, an engagement device reciprocably disposed externally on the housing and secured relative to the mandrel, so that the mandrel displaces with the engagement device, and a biasing device that biases the mandrel and engagement device in a selected longitudinal direction. A system can include a tubular string and a valve assembly reciprocably disposed in the tubular string, the valve assembly including a valve that selectively restricts flow through a longitudinal passage. The valve closes in response to displacement of the valve assembly in a selected longitudinal direction relative to the tubular string, and the valve opens in response to displacement of the valve assembly in the same longitudinal direction relative to the tubular string.

Abstract: The present disclosure addresses apparatus and methods for forming an annular isolator in a borehole after installation of production tubing. A first deployable annular isolator is carried on tubing as it is positioned in a borehole. An annular isolator forming material is placed in the annulus around the first deployable isolator. The first isolator is then deployed into the material in the annulus to form a combined isolator. The annular isolator forming material is carried in a compartment in the tubing and forced from the compartment into the annulus. A second deployable isolator may be deployed before placing the material in the annulus to resist annular flow of the material before the first isolator is deployed. The second isolator may be deployed by material from the compartment. A second compartment may be provided to deploy the first isolator.