Abstract: A gas vent tool can include a body with a flow passage having upstream and downstream sections, a valve that selectively permits and blocks flow between the upstream section and an exterior of the gas vent tool, and a valve that selectively permits and blocks flow between the upstream and downstream sections. A gas vent system can include a gas vent tool connected longitudinally between an intake tool and a pump, the intake tool being configured to receive formation fluids therein, and the pump being configured to pump the formation fluids to surface. The gas vent tool can include a valve that selectively permits and blocks flow between an interior flow passage and an annulus external to the gas vent tool, and a valve that selectively permits and blocks flow between upper and lower sections of the flow passage.

Abstract: A surge flow mitigation tool can include a surge flow valve that permits one-way fluid flow through a flow passage, and a bypass flow path that opens when a differential pressure across the surge flow valve is greater than a predetermined level. A method of mitigating surge flow in a well can include producing fluid through a tubular string with a bottom hole assembly including a surge flow mitigation tool connected downhole of a packer, the surge flow mitigation tool including a surge flow valve that permits the fluid to flow toward surface via the tubular string, but prevents the fluid from flowing into the well via the tubular string, and increasing a differential pressure across the surge flow valve to greater than a predetermined level, thereby opening a bypass flow path that permits injection flow from the tubular string into the well downhole of the packer.

Abstract: A vortex de-sanding system can include a packer having an annular seal element, a flow passage extending longitudinally through the packer, and at least one opening formed through a wall of the packer, the opening permitting fluid communication between the flow passage and an exterior of the packer, and a vortex de-sanding tool connected to the packer. The vortex de-sanding tool can include an inner production flow tube, an outer sleeve surrounding the flow tube and having at least one port formed through a wall of the outer sleeve, an abrasion resistant housing surrounding the flow tube, and a helical vane positioned in an annulus formed between the flow tube and the housing. The flow passage extends longitudinally through the flow tube, and the housing has a surface abrasion resistance greater than a surface abrasion resistance of the inner production flow tube.

Abstract: A gas separation system can include a gas separator tool, and a gas discharge tool including an inner flow passage formed through a tube and configured to convey separated liquids, and discharge ports configured to discharge well fluids upwardly into an area surrounding the tube. A method of separating gas from liquids of well fluids produced from a subterranean well can include connecting a gas separator tool and a gas discharge tool to a production tubing string, positioning the gas separator tool and the gas discharge tool in the well, so that the well fluids are produced into the gas separator tool, receiving the well fluids from the gas separator tool into the gas discharge tool, and discharging the well fluids from the gas discharge tool into a radially enlarged section of an annulus surrounding the gas discharge tool.

Abstract: A gas vent can include an inner production tube and at least two outer housings. One outer housing is configured to be connected above a tubing anchor, and another outer housing is configured to be connected below the tubing anchor. The inner production tube is configured to extend longitudinally through the tubing anchor. A gas vent system can include an inner production tube which extends longitudinally through a tubing anchor, and an annulus formed between the inner production tube and the tubing anchor. A gas flows through an interior of the tubing anchor via the annulus.

Abstract: A chemical treatment assembly can include a section including a pressure containment valve that selectively permits and prevents fluid communication with a flow passage in the section, and another section including a pressure containment valve that selectively permits and prevents fluid communication with a flow passage in the section. The pressure containment valves are closed in response to disconnection of the sections. A method of containing pressure in sections of a chemical treatment assembly can include installing a pressure containment valve in each of the sections, the pressure containment valves being configured to close in response to disconnecting the sections. Another chemical treatment assembly can include an outer housing, a flow passage extending longitudinally through the outer housing, a chemical treatment positioned in the flow passage, and a pressure containment valve that selectively permits and prevents fluid communication with the flow passage through the pressure containment valve.

Abstract: A sand lift tool for use in a subterranean well can include an outer housing, an inner production tube positioned in the outer housing, and a dart received in the inner production tube. An annulus is positioned between the outer housing and the inner production tube. The dart can reciprocate in the inner production tube in response to variations in fluid flow between the annulus and an interior of the inner production tube. Another sand lift tool can include an outer housing, an inner production tube, and a sand collection annulus between the outer housing and the inner production tube. A flow area for fluid flow between the annulus and an interior of the inner production tube increases in response to an increase in a flow rate of the fluid flow.

Abstract: A gas separator can include an intake section. Splines extend radially from an inner manifold of the intake section and engage an interior surface of an outer housing, thereby isolating openings formed in the splines from longitudinal channels extending through the outer housing. Another gas separator can include an intake section, a discharge section and multiple intermediate sections connected between the intake and discharge sections. A gas separation system can include a completion string including a packer, a downhole pump and a gas separator connected between the packer and the pump. An annulus is formed between the gas separator and a wellbore, an intake section of the gas separator receives formation fluids from below the packer, a discharge section of the gas separator discharges gas and liquids into the annulus, the intake section receives the liquids from the annulus, and the pump receives the liquids from the discharge section.

Abstract: A surge flow mitigation tool can include a surge flow valve that permits one-way fluid flow through a flow passage, and a bypass flow path that opens when a differential pressure across the surge flow valve is greater than a predetermined level. A method of mitigating surge flow in a well can include producing fluid through a tubular string with a bottom hole assembly including a surge flow mitigation tool connected downhole of a packer, the surge flow mitigation tool including a surge flow valve that permits the fluid to flow toward surface via the tubular string, but prevents the fluid from flowing into the well via the tubular string, and increasing a differential pressure across the surge flow valve to greater than a predetermined level, thereby opening a bypass flow path that permits injection flow from the tubular string into the well downhole of the packer.

Abstract: A vortex de-sanding system can include a packer having an annular seal element, a flow passage extending longitudinally through the packer, and at least one opening formed through a wall of the packer, the opening permitting fluid communication between the flow passage and an exterior of the packer, and a vortex de-sanding tool connected to the packer. The vortex de-sanding tool can include an inner production flow tube, an outer sleeve surrounding the flow tube and having at least one port formed through a wall of the outer sleeve, an abrasion resistant housing surrounding the flow tube, and a helical vane positioned in an annulus formed between the flow tube and the housing. The flow passage extends longitudinally through the flow tube, and the housing has a surface abrasion resistance greater than a surface abrasion resistance of the inner production flow tube.

Abstract: A sand lift tool for use in a subterranean well can include an outer housing, an inner production tube positioned in the outer housing, and a dart received in the inner production tube. An annulus is positioned between the outer housing and the inner production tube. The dart can reciprocate in the inner production tube in response to variations in fluid flow between the annulus and an interior of the inner production tube. Another sand lift tool can include an outer housing, an inner production tube, and a sand collection annulus between the outer housing and the inner production tube. A flow area for fluid flow between the annulus and an interior of the inner production tube increases in response to an increase in a flow rate of the fluid flow.

Abstract: A gas vent tool can include a body with a flow passage having upstream and downstream sections, a valve that selectively permits and blocks flow between the upstream section and an exterior of the gas vent tool, and a valve that selectively permits and blocks flow between the upstream and downstream sections. A gas vent system can include a gas vent tool connected longitudinally between an intake tool and a pump, the intake tool being configured to receive formation fluids therein, and the pump being configured to pump the formation fluids to surface. The gas vent tool can include a valve that selectively permits and blocks flow between an interior flow passage and an annulus external to the gas vent tool, and a valve that selectively permits and blocks flow between upper and lower sections of the flow passage.

Abstract: A chemical treatment assembly can include a section including a pressure containment valve that selectively permits and prevents fluid communication with a flow passage in the section, and another section including a pressure containment valve that selectively permits and prevents fluid communication with a flow passage in the section. The pressure containment valves are closed in response to disconnection of the sections. A method of containing pressure in sections of a chemical treatment assembly can include installing a pressure containment valve in each of the sections, the pressure containment valves being configured to close in response to disconnecting the sections. Another chemical treatment assembly can include an outer housing, a flow passage extending longitudinally through the outer housing, a chemical treatment positioned in the flow passage, and a pressure containment valve that selectively permits and prevents fluid communication with the flow passage through the pressure containment valve.

Abstract: A gas separator can include an intake section. Splines extend radially from an inner manifold of the intake section and engage an interior surface of an outer housing, thereby isolating openings formed in the splines from longitudinal channels extending through the outer housing. Another gas separator can include an intake section, a discharge section and multiple intermediate sections connected between the intake and discharge sections. A gas separation system can include a completion string including a packer, a downhole pump and a gas separator connected between the packer and the pump. An annulus is formed between the gas separator and a wellbore, an intake section of the gas separator receives formation fluids from below the packer, a discharge section of the gas separator discharges gas and liquids into the annulus, the intake section receives the liquids from the annulus, and the pump receives the liquids from the discharge section.

Abstract: A downhole fluid separation apparatus can include multiple sections connected together with connectors, the connectors providing fluid communication between annuli in adjacent ones of the sections, and between inner conduits in adjacent ones of the sections. Each connector can include at least one flow passage providing communication between an inner conduit of each of the connected sections, and another flow passage providing communication between an annulus of each of the connected sections. A bypass valve can be included that opens in response to a predetermined differential pressure between an exterior of the apparatus and the inner conduits.

Abstract: A downhole fluid separation apparatus can include multiple sections connected together with connectors, the connectors providing fluid communication between annuli in adjacent ones of the sections, and between inner conduits in adjacent ones of the sections. Each connector can include at least one flow passage providing communication between an inner conduit of each of the connected sections, and another flow passage providing communication between an annulus of each of the connected sections. A bypass valve can be included that opens in response to a predetermined differential pressure between an exterior of the apparatus and the inner conduits.