Downhole device employing electromagnet assemblies separated by a lesser distance (dem) and ferromagnet assembly to actuate a movable feature

A method, comprising:

• accessing a downhole device located within a wellbore extending through one or more subterranean formations, wherein the downhole device includes:
• a member having a first member end and a second opposite member end;
• a movable element positioned about the member, the movable element having a first movable element end and a second opposite movable element end, the movable element configured to move a stroke distance (D) from a first position to a second position;
• a ferromagnet assembly fixed to one of the member or the movable element;
• a first electromagnet assembly fixed to an other of the movable element or the member;
• and
• a second electromagnet assemblies fixed to the other of the movable element or the member sequentially further from the first member end than the first electromagnet assembly, the first and second electromagnet assemblies each having a width (WEM) and separated by a distance (DEM), wherein the distance (DEM) is less than each width (WEM);
• and
• supplying electric power to the first and second electromagnet assemblies to produce first and second electromagnetic fields, the first and second electromagnetic fields actuating the movable element from the first position toward the second position.

A well system, comprising:

• a wellbore extending through one or more subterranean formations;
• and
• a downhole device located within the wellbore, the downhole device including:
• a member having a first member end and a second opposite member end;
• a movable element positioned about the member, the movable element having a first movable element end and a second opposite movable element end, the movable element configured to move a stroke distance (D) from a first position to a second position;
• a ferromagnet assembly fixed to one of the member or the movable element;
• a first electromagnet assembly fixed to an other of the movable element or the member;
• and
• a second electromagnet assemblies fixed to the other of the movable element or the member sequentially further from the first member end than the first electromagnet assembly, the first and second electromagnet assemblies each having a width (WEM) and separated by a distance (DEM), wherein the distance (DEM) is less than each width (WEM), and further wherein the first and second electromagnet assemblies are operable to receive electric power to produce first and second electromagnetic fields, the first and second electromagnetic fields configured to actuate the movable element from the first position toward the second position.