A system is provided that includes a dart, a pressure sensor, and a controller communicatively coupled with the sensor. The dart is disposed in a fluidic channel. The dart has a main body and a flange extending from the main body and has a diameter greater than or equal to a diameter of the fluidic channel. When the dart translates within the fluidic channel and passes a location of a variation in the fluidic channel, the flange creates a pressure pulse. The pressure sensor measures the pressure pulse within the fluidic channel created by the dart. The controller determines the location of the variation based on the measured pressure pulse.

Described are systems and methods for evaluating the leak safety of threaded connections in well tubulars. A method, for example, includes assessing leak risk according to a Leak Criterion with Thread Shear. The Leak Criterion with Thread Shear is a function of the conditions relative to a pin-box interface radius and includes two constants: a Thread Modulus (alpha) and a Makeup Leak Resistance (beta). The leak risk is evaluated at the pin-box interface and is a function of differential pressure, effective stress, and shear stress. Lab tests conducted under known conditions are described for calculating the constants, alpha and beta, which are independent of extrinsic states or conditions.

Described are systems and methods for evaluating the leak safety of threaded connections in well tubulars. A method, for example, includes assessing leak risk according to a Leak Criterion with Thread Shear. The Leak Criterion with Thread Shear is a function of the conditions relative to a pin-box interface radius and includes two constants: a Thread Modulus (alpha) and a Makeup Leak Resistance (beta). The leak risk is evaluated at the pin-box interface and is a function of differential pressure, effective stress, and shear stress. Lab tests conducted under known conditions are described for calculating the constants, alpha and beta, which are independent of extrinsic states or conditions.

A method of sealing one or more leak paths includes positioning an isolation plug in a production tubing. The production tubing is disposed within a wellbore casing assembly, each extending into a subsurface. The wellbore casing assembly includes a production casing. A tubing/casing annulus is disposed between the production casing and the production tubing. The one or more leak paths are fluidly coupled to the production tubing and the tubing/casing annulus and the isolation plug is positioned at a depth location below the one or more leak paths. The method also includes perforating the production tubing at a depth location above the isolation plug to form one or more sealant injection holes fluidly coupling the production tubing and the tubing/casing annulus and directing a sealant into the production tubing such that the sealant enters the tubing/casing annulus through the one or more sealant injection holes.

A method of sealing one or more leak paths includes positioning an isolation plug in a production tubing. The production tubing is disposed within a wellbore casing assembly, each extending into a subsurface. The wellbore casing assembly includes a production casing. A tubing/casing annulus is disposed between the production casing and the production tubing. The one or more leak paths are fluidly coupled to the production tubing and the tubing/casing annulus and the isolation plug is positioned at a depth location below the one or more leak paths. The method also includes perforating the production tubing at a depth location above the isolation plug to form one or more sealant injection holes fluidly coupling the production tubing and the tubing/casing annulus and directing a sealant into the production tubing such that the sealant enters the tubing/casing annulus through the one or more sealant injection holes.

A pressure-testing system for a tubular product. Preferably, the tubular product is a joint or a stand of production tubing. The pressure testing assembly includes a controller; a fluid reservoir configured to contain a test fluid; a pump in fluid communication with the fluid reservoir; a fluid hose having a first end configured to receive the test fluid from the reservoir, and a second end configured to be fluidically connected to a hydrotest tool for the tubular product; and a transducer. The transducer sends signals to the controller indicative of pressure within the fluid hose. The controller is programmed to automatically (i) store a pressure threshold value (T) such that when pressure in the fluid hose reaches (T), the controller sends a signal to the pump to discontinue pumping; and (ii) store a pressure test value (P.sub.T) such when pressure in the fluid hose reaches (P.sub.T), the controller sends a signal to the pump to discontinue pumping.

A pressure-testing system for a tubular product. Preferably, the tubular product is a joint or a stand of production tubing. The pressure testing assembly includes a controller; a fluid reservoir configured to contain a test fluid; a pump in fluid communication with the fluid reservoir; a fluid hose having a first end configured to receive the test fluid from the reservoir, and a second end configured to be fluidically connected to a hydrotest tool for the tubular product; and a transducer. The transducer sends signals to the controller indicative of pressure within the fluid hose. The controller is programmed to automatically (i) store a pressure threshold value (T) such that when pressure in the fluid hose reaches (T), the controller sends a signal to the pump to discontinue pumping; and (ii) store a pressure test value (P.sub.T) such when pressure in the fluid hose reaches (P.sub.T), the controller sends a signal to the pump to discontinue pumping.

An estimated gas leak flow rate can be determined using a teaching set of concentration profiles, a regression model implemented by a machine-learning subsystem, and a subset of attributes measured within an environment. The teaching set of concentration profiles can include gas flow rates associated with relevant attributes. The regression model can be transformed into a gas leak flow regression model via the machine-learning subsystem using the teaching set. The subset of attributes measured within the environment can be applied to the gas leak flow regression model to determine other attributes absent from the subset of attributes and an estimated gas flow rate for the environment. A gas leak attenuation action can be performed in response to the estimated gas flow rate.

An estimated gas leak flow rate can be determined using a teaching set of concentration profiles, a regression model implemented by a machine-learning subsystem, and a subset of attributes measured within an environment. The teaching set of concentration profiles can include gas flow rates associated with relevant attributes. The regression model can be transformed into a gas leak flow regression model via the machine-learning subsystem using the teaching set. The subset of attributes measured within the environment can be applied to the gas leak flow regression model to determine other attributes absent from the subset of attributes and an estimated gas flow rate for the environment. A gas leak attenuation action can be performed in response to the estimated gas flow rate.

A toe valve for use in a wellbore includes: a tubular mandrel; a housing extending along a periphery of the mandrel; couplings at longitudinal ends of the toe valve for assembly as part of a casing or liner string; a valve piston disposed in an annulus formed between the housing and the mandrel, movable between an open position and a closed position, and disposed between a valve port of the housing and a valve port of the mandrel in the closed position; an atmospheric chamber for facilitating movement of the valve piston to the open position; a vent port formed through the housing and in fluid communication with the atmospheric chamber; and a flow control device disposed in the vent port and operable to prevent fluid flow from the wellbore into the atmospheric chamber and allow fluid flow from the atmospheric chamber into the wellbore.