Abstract: A capping stack for use with a subsea well includes a ball valve disposed along a first flowline that is axially aligned with a main flowbore of a manifold body so that a tubing string can be passed through the ball valve into the well and whereby the ball valve can be activated to both close the flowline and sever the tubing string as desired. The main flowbore of the manifold body is defined along a primary axis and the capping stack includes second and third flowlines that each intersect the primary axis at an angle greater than zero and that each include a choke mechanism and a pair of spaced apart ball valves disposed along the flowline.

Abstract: A method can include measuring temperature along a relief wellbore, thereby detecting a temperature anomaly in an earth formation penetrated by the relief wellbore, and determining a location of an influx into a target wellbore, based on the temperature anomaly detecting. A thermal anomaly ranging system for use with a subterranean well can include a temperature sensor in a relief wellbore that penetrates an earth formation, the temperature sensor detecting a temperature anomaly in the formation, and the temperature anomaly being caused by an influx into a target wellbore. Another method can include measuring optical scattering in an optical waveguide positioned in a relief wellbore, thereby detecting a temperature anomaly in an earth formation penetrated by the relief wellbore, and determining a location of an influx into a target wellbore, based on the temperature anomaly detecting.

Abstract: A method of establishing fluid communication between wellbores can include forming a flow path from one wellbore to another wellbore, a flow area of the flow path increasing in a direction from the first wellbore toward the second wellbore. An explosive assembly for use in a well can include an explosive device having multiple explosive charges, the explosive charges producing longitudinal shock waves that collide with each other and result in a laterally directed shock wave, and a shield that focuses the laterally directed shock wave into a predetermined angular range of less than 360 degrees. A method of establishing fluid communication between wellbores can include forming a flow path from one wellbore to another wellbore, the flow path intersecting an uncased portion of the second wellbore.

Abstract: A method can include measuring microseismic activity in a relief wellbore, thereby detecting a microseismic event in an earth formation penetrated by the relief wellbore, and determining a location of an influx into a target wellbore, based on the microseismic event detecting. A microseismic ranging system for use with a subterranean well can include at least one microseismic sensor in a relief wellbore that penetrates an earth formation, with the microseismic sensor detecting a microseismic event in the formation, the microseismic event being caused by an influx into a target wellbore. Another method can include measuring optical scattering in an optical waveguide positioned in a relief wellbore, thereby detecting a microseismic event in an earth formation penetrated by the relief wellbore, and determining a location of an influx into a target wellbore, based on the microseismic event detecting.

Abstract: A method of establishing fluid communication between wellbores can include forming a flow path from one wellbore to another wellbore, a flow area of the flow path increasing in a direction from the first wellbore toward the second wellbore. An explosive assembly for use in a well can include an explosive device having multiple explosive charges, the explosive charges producing longitudinal shock waves that collide with each other and result in a laterally directed shock wave, and a shield that focuses the laterally directed shock wave into a predetermined angular range of less than 360 degrees. A method of establishing fluid communication between wellbores can include forming a flow path from one wellbore to another wellbore, the flow path intersecting an uncased portion of the second wellbore.

Abstract: A method can include measuring microseismic activity in a relief wellbore, thereby detecting a microseismic event in an earth formation penetrated by the relief wellbore, and determining a location of an influx into a target wellbore, based on the microseismic event detecting. A microseismic ranging system for use with a subterranean well can include at least one microseismic sensor in a relief wellbore that penetrates an earth formation, with the microseismic sensor detecting a micro seismic event in the formation, the microseismic event being caused by an influx into a target wellbore. Another method can include measuring optical scattering in an optical waveguide positioned in a relief wellbore, thereby detecting a microseismic event in an earth formation penetrated by the relief wellbore, and determining a location of an influx into a target wellbore, based on the microseismic event detecting.

Abstract: A method can include measuring temperature along a relief wellbore, thereby detecting a temperature anomaly in an earth formation penetrated by the relief wellbore, and determining a location of an influx into a target wellbore, based on the temperature anomaly detecting. A thermal anomaly ranging system for use with a subterranean well can include a temperature sensor in a relief wellbore that penetrates an earth formation, the temperature sensor detecting a temperature anomaly in the formation, and the temperature anomaly being caused by an influx into a target wellbore. Another method can include measuring optical scattering in an optical waveguide positioned in a relief wellbore, thereby detecting a temperature anomaly in an earth formation penetrated by the relief wellbore, and determining a location of an influx into a target wellbore, based on the temperature anomaly detecting.

Abstract: An electromagnetic ranging source includes: a tubular body having a circumference; a ferromagnetic core conforming to the tubular body and extending at least halfway around the circumference to define a gap with circumferentially-spaced poles; one or more current-carrying windings around the core to induce a magnetic field between the poles; and a downhole power source that drives the one or more current-carrying windings. A related method includes: equipping a first drill string with such an electromagnetic ranging source; extending a first borehole with the first drill string; assembling a second drill string with sensors; and drilling a second borehole while using said sensors to guide the second drill string relative to the first borehole.

Abstract: A method of establishing fluid communication between wellbores can include forming a flow path from one wellbore to another wellbore, a flow area of the flow path increasing in a direction from the first wellbore toward the second wellbore. An explosive assembly for use in a well can include an explosive device having multiple explosive charges, the explosive charges producing longitudinal shock waves that collide with each other and result in a laterally directed shock wave, and a shield that focuses the laterally directed shock wave into a predetermined angular range of less than 360 degrees. A method of establishing fluid communication between wellbores can include forming a flow path from one wellbore to another wellbore, the flow path intersecting an uncased portion of the second wellbore.

Abstract: An electromagnetic ranging source embodiment includes: a tubular body having a circumference; a ferromagnetic core conforming to the tubular body and extending at least halfway around the circumference to define a gap with circumferentially-spaced poles; one or more current-carrying windings around the core to induce a magnetic field between the poles; and a downhole power source that drives the one or more current-carrying windings. A method embodiment includes: equipping a first drill string with such an electromagnetic ranging source; extending a first borehole with the first drill string; assembling a second drill string with sensors; and drilling a second borehole while using said sensors to guide the second drill string relative to the first borehole.