Abstract: A downhole tool, for removing sections of metal tubing, said downhole tool comprising at least one conductive element being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element being made of electric conductive material, an apparatus to establish a connection to the metal tubing, and a source of electrical power.

Abstract: A downhole tool, for removing sections of metal tubing, said downhole tool comprising at least one conductive element being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element being made of electric conductive material, an apparatus to establish a connection to the metal tubing, and a source of electrical power.

Abstract: There is provided a method of chemically removing iron-containing casing from a well bore comprising injecting an acidic solution into said well bore, wherein said solution contacts said iron-containing casing and thereby accelerates oxidation of iron to iron cations, allowing said iron cations to dissolve in said solution, and removing said solution from said well bore. There is further provided a batch method of removing iron-containing casing from a well bore comprising injecting an acidic solution into said well bore, wherein said acidic solution contacts said iron-containing casing and thereby accelerates oxidation of iron to iron cations, and allowing said iron cations to dissolve in said acidic solution, wherein said well bore is at least partially open to the atmosphere.

Abstract: A downhole tool, for removing sections of metal tubing, said downhole tool comprising at least one conductive element being arranged to corrode a section of metal tubing using an electrolytic process, said conductive element being made of electric conductive material, an apparatus to establish a connection to the metal tubing, and a source of electrical power.

Abstract: There is provided a method for removing iron-containing casing from a well bore comprising providing a cathode in said well bore, wherein said cathode is connected to the negative pole of a power source; connecting said iron-containing casing to the positive pole of said power source; injecting an electrolyte into said well bore, wherein said electrolyte contacts said iron-containing casing and said cathode; applying a current so that the iron in said iron-containing casing is oxidised to iron cations; allowing said iron cations to dissolve in said electrolyte; and removing said electrolyte from said well bore. Also provided are a system for removing iron-containing casing from a well bore, a method for monitoring the removal of an iron-containing casing from a well bore and a method for plugging and abandoning a well.

Abstract: A method and apparatus for determining the location of a material located behind an obstruction. A plurality of acoustic resonators (6) having a known resonant frequency are dispersed in the material (3), the material to be located on a first side of the obstruction (2). An instrument (5) is provided at an opposite side of the obstruction to the material. The instrument emits an acoustic signal and measures a response. If the resonant frequency is detected, it is determined that the material is located substantially adjacent to the instrument. The apparatus may be used for determining the height of cement slurry located between a well casing wall and a borehole.

Abstract: There is provided a method for removing iron-containing casing from a well bore comprising providing a cathode in said well bore, wherein said cathode is connected to the negative pole of a power source; connecting said iron-containing casing to the positive pole of said power source; injecting an electrolyte into said well bore, wherein said electrolyte contacts said iron-containing casing and said cathode; applying a current so that the iron in said iron-containing casing is oxidised to iron cations; allowing said iron cations to dissolve in said electrolyte; and removing said electrolyte from said well bore. Also provided are a system for removing iron-containing casing from a well bore, a method for monitoring the removal of an iron-containing casing from a well bore and a method for plugging and abandoning a well.

Abstract: There is provided a method of chemically removing iron-containing casing from a well bore comprising injecting an acidic solution into said well bore, wherein said solution contacts said iron-containing casing and thereby accelerates oxidation of iron to iron cations, allowing said iron cations to dissolve in said solution, and removing said solution from said well bore. There is further provided a batch method of removing iron-containing casing from a well bore comprising injecting an acidic solution into said well bore, wherein said acidic solution contacts said iron-containing casing and thereby accelerates oxidation of iron to iron cations, and allowing said iron cations to dissolve in said acidic solution, wherein said well bore is at least partially open to the atmosphere.

Abstract: The invention provides a method for the protection of internal filters of a LTFT slurry bubble reactor. The method includes the step of activating an emergency back-flush procedure during low slurry level conditions and/or during increasing temperature of an internal filter.

Abstract: The invention provides a method for the separation of liquid from a three phase slurry bubble column. The method includes the step of charging the inside of a hollow filter element with a rinsing fluid to clean the inside of the filter for catalyst fines followed by a backflushing step. The invention also provides an installation for the separation of liquid from a three phase slurry bubble column. The installation includes at feast one hollow and enclosed filter element and one or more conduits in fluid communication with the internal volume of the filter, with at least one conduit being configured or connected for inflow of rinsing fluid and at least one conduit being configured or connection for outflow of rinsing fluid.

Abstract: A method and apparatus for determining the location of a material located behind an obstruction. A plurality of acoustic resonators (6) having a known resonant frequency are dispersed in the material (3), the material to be located on a first side of the obstruction (2). An instrument (5) is provided at an opposite side of the obstruction to the material. The instrument emits an acoustic signal and measures a response. If the resonant frequency is detected, it is determined that the material is located substantially adjacent to the instrument. The apparatus may be used for determining the height of cement slurry located between a well casing wall and a borehole.

Abstract: The invention provides a method for the protection of internal filters of a LTFT slurry bubble reactor. The method includes the step of activating an emergency back-flush procedure during low slurry level conditions and/or during increasing temperature of an internal filter.

Abstract: The invention provides a method for the separation of liquid from a three phase slurry bubble column. The method includes the step of charging the inside of a hollow filter element with a rinsing fluid to clean the inside of the filter for catalyst fines followed by a backflushing step. The invention also provides an installation for the separation of liquid from a three phase slurry bubble column. The installation includes at least one hollow and enclosed filter element and one or more conduits in fluid communication with the internal volume of filter, with at least one conduit being configured or connected for inflow of rinsing fluid and at least one conduit being configured or connected for outflow of rinsing fluid.