Abstract: A work string and method of performing a downhole operation is disclosed. The work string includes a first tool having a first ball seat configured to activate when a first activation pressure is applied to a plug seated at the first ball seat, and a second tool having a second ball seat configured to activate when a second activation pressure is applied to the plug when seated at the second ball seat, wherein the first activation pressure is different than the second activation pressure. A plug is dropped through a string in a wellbore. The first activation pressure is applied when the plug is at the first tool to activate the first tool. The second activation pressure is applied when the plug is at the second tool to activate the second tool.

Abstract: A work string and method of performing a downhole operation is disclosed. The work string includes a first tool having a first ball seat configured to activate when a first activation pressure is applied to a plug seated at the first ball seat, and a second tool having a second ball seat configured to activate when a second activation pressure is applied to the plug when seated at the second ball seat, wherein the first activation pressure is different than the second activation pressure. A plug is dropped through a string in a wellbore. The first activation pressure is applied when the plug is at the first tool to activate the first tool. The second activation pressure is applied when the plug is at the second tool to activate the second tool.

Abstract: A milling apparatus for cutting a tubular in a wellbore includes a cutting element on a tool body configured to cut the tubular in a wellbore when the cutting element is activated when the tool is moving upward inside the tubular. The cutting element cuts the tubular to form cuttings that fall into an annulus between the tubular and the wellbore. An agitator below the cutting element agitates the cuttings in the annulus to aid the cuttings to move from the annulus into the wellbore below the milling apparatus.

Abstract: Dual section mills are selectively sequentially operated by locking an actuator for the backup mill as the primary mill has blades extended with internal flow through a housing. When the primary mill is spent the support string is shifted to defeat a lock on an actuation piston for the backup mill so that its blades can extend and continue to mill to finish the job. The blades of the primary mill continue to rotate in the already milled portion of the window as the secondary mill enlarges the window. Another way the secondary mill is actuated is to open access to flow to the secondary mill by removing a pressure barrier such as a valve or a disappearing plug, for example.

Abstract: A milling apparatus for cutting a tubular in a wellbore includes a cutting element on a tool body configured to cut the tubular in a wellbore when the cutting element is activated when the tool is moving upward inside the tubular. The cutting element cuts the tubular to form cuttings that fall into an annulus between the tubular and the wellbore. An agitator below the cutting element agitates the cuttings in the annulus to aid the cuttings to move from the annulus into the wellbore below the milling apparatus.

Abstract: The cutting structure on the lower mill is arrayed in rows that are preferably parallel. The cutting structure in each row is made sharper and more durable than prior designs with the objective of cutting the window higher than where the window mill started the window. The use of the rows increases the contact stress of the inserts on the casing inside wall because at any given time fewer and sharper inserts are cutting the casing wall to lengthen the window. As a row wears down the next row takes over to continue the cutting where the previous row was active and to further penetrate the casing wall. The cutout angle can also increase as this occurs. As a result a decreased insert density results in more effective casing wall cutting to extend the window to allow larger tools to exit into the window off the whipstock.

Abstract: Dual section mills are selectively sequentially operated by locking an actuator for the backup mill as the primary mill has blades extended with internal flow through a housing. When the primary mill is spent the support string is shifted to defeat a lock on an actuation piston for the backup mill so that its blades can extend and continue to mill to finish the job. The blades of the primary mill continue to rotate in the already milled portion of the window as the secondary mill enlarges the window. Another way the secondary mill is actuated is to open access to flow to the secondary mill by removing a pressure barrier such as a valve or a disappearing plug, for example.

Abstract: A cutting device includes, at least one stack of cutting elements attached to a cutter surface having, a first element and a second element attached to the cutter surface. A third element is attached to the first element and the second element. The three elements are sized and shaped such that prior to attachment to the cutter surface the three elements are restable in a stable manner on the cutter surface due to gravity alone. A plane-defined-surface defined by one of the two planes of a modified gilmoid of the third element positioned further from the cutter surface is oriented at an angle of about 35 to 55 degrees relative to the cutter surface.

Abstract: The cutting structure on the lower mill is arrayed in rows that are preferably parallel. The cutting structure in each row is made sharper and more durable than prior designs with the objective of cutting the window higher than where the window mill started the window. The use of the rows increases the contact stress of the inserts on the casing inside wall because at any given time fewer and sharper inserts are cutting the casing wall to lengthen the window. As a row wears down the next row takes over to continue the cutting where the previous row was active and to further penetrate the casing wall. The cutout angle can also increase as this occurs. As a result a decreased insert density results in more effective casing wall cutting to extend the window to allow larger tools to exit into the window off the whipstock.

Abstract: The cutting structure on the lower mill is arrayed in rows that are preferably parallel. The cutting structure in each row is made sharper and more durable than prior designs with the objective of cutting the window higher than where the window mill started the window. The use of the rows increases the contact stress of the inserts on the casing inside wall because at any given time fewer and sharper inserts are cutting the casing wall to lengthen the window. As a row wears down the next row takes over to continue the cutting where the previous row was active and to further penetrate the casing wall. The cutout angle can also increase as this occurs. As a result a decreased insert density results in more effective casing wall cutting to extend the window to allow larger tools to exit into the window off the whipstock.

Abstract: The cutting structure on the lower mill is arrayed in rows that are preferably parallel. The cutting structure in each row is made sharper and more durable than prior designs with the objective of cutting the window higher than where the window mill started the window. The use of the rows increases the contact stress of the inserts on the casing inside wall because at any given time fewer and sharper inserts are cutting the casing wall to lengthen the window. As a row wears down the next row takes over to continue the cutting where the previous row was active and to further penetrate the casing wall. The cutout angle can also increase as this occurs. As a result a decreased insert density results in more effective casing wall cutting to extend the window to allow larger tools to exit into the window off the whipstock.

Abstract: A cutting device includes, at least one stack of cutting elements attached to a cutter surface having, a first element and a second element attached to the cutter surface, and a third element attached to the first element and the second element, the three elements being sized and shaped such that prior to attachment to the cutter surface the three elements are restable in a stable manner on the cutter surface due to gravity alone such that a plane-defined-surface defined by one of the two planes of a modified gilmoid of the third element positioned further from the cutter surface is oriented at an angle of about 35 to 55 degrees relative to the cutter surface.

Abstract: Cutting elements for downhole cutting tools comprise a top surface having a cutting surface portion and a cutting profile disposed across the top surface. The cutting elements comprise first and second longitudinal side surfaces and first and second lateral side surfaces, each having a respective cross-section. The cutting profile can be disposed on the cutting surface either asymmetrically or symmetrically. Asymmetrical disposition permits two cutting elements to be arranged facing each other to cover a center point of a cutting tool. The cutting edge of asymmetrical or symmetrically disposed cutting profiles can have a shape that facilitates self-sharpening during cutting.

Abstract: A milling tool which includes a nose cutting portion, a cutting section having a plurality of hardened cutters and a shaft portion. A wear pad is disposed on the cutting section and shaft portion. Upon the shaft portion, the wear pad extends radially outwardly to an engagement diameter that exceeds the maximum cutting diameter of the cutters.

Abstract: Earth-boring tools comprise a face and a plurality of cutting elements disposed on at least a portion of the face. An impact material is positioned on at least one portion of a body and has a relative exposure equal to or greater than at least some of the cutting elements of the plurality of cutting elements. The impact material comprises a material having a lower abrasion resistance than the body. Methods of making and methods of using such earth-boring tools.

Abstract: Cutting elements for downhole cutting tools comprise a top surface having a cutting surface portion and a cutting profile asymmetrically disposed across the top surface. The cutting elements comprise first and second longitudinal side surfaces and first and second lateral side surfaces, each having a respective cross-section. The cross-section of one of the longitudinal side surfaces can have one beveled portion and the cross-sections of the other longitudinal side surface and the first and second lateral side surfaces can have two beveled portions. A cutting end of a downhole cutting tool comprises two cutting elements disposed facing each another with a portion of the cutting surface portion of a first cutting element being disposed opposite the cutting profile of the second cutting element and the cutting surface portion of the second cutting element being disposed opposite the cutting profile of the first cutting element.

Abstract: Downhole cutting tools such as blade mills comprise a body having a first end for connection with a rotating component of a drill string and a cutting end for rotation in unison with the body. The cutting end comprises at least two blades, each of the at least two blades comprising a front sidewall surface, a back sidewall surface, an inner end, an outer end, and at least one beveled portion disposed along the front sidewall surface toward the inner end of each of the at least two blades. At least one of the beveled portions comprise at least one cutting element disposed thereon that is disposed across a center point of the face of the cutting end to provide for cutting away an object disposed in a wellbore to occur across a center point of the cutting end.

Abstract: Cutting elements for downhole cutting tools comprise a top surface having a cutting surface portion and a cutting profile asymmetrically disposed across the top surface. The cutting elements comprise first and second longitudinal side surfaces and first and second lateral side surfaces, each having a respective cross-section. The cross-section of one of the longitudinal side surfaces can have one beveled portion and the cross-sections of the other longitudinal side surface and the first and second lateral side surfaces can have two beveled portions. A cutting end of a downhole cutting tool comprises two cutting elements disposed facing each another with a portion of the cutting surface portion of a first cutting element being disposed opposite the cutting profile of the second cutting element and the cutting surface portion of the second cutting element being disposed opposite the cutting profile of the first cutting element.

Abstract: Cutting elements for downhole cutting tools comprise a top surface having a cutting surface portion and a cutting profile disposed across the top surface. The cutting elements comprise first and second longitudinal side surfaces and first and second lateral side surfaces, each having a respective cross-section. The cutting profile can be disposed on the cutting surface either asymmetrically or symmetrically. Asymmetrical disposition permits two cutting elements to be arranged facing each other to cover a center point of a cutting tool. The cutting edge of asymmetrical or symmetrically disposed cutting profiles can have a shape that facilitates self-sharpening during cutting.

Abstract: Downhole cutting tools such as blade mills comprise a body having a first end for connection with a rotating component of a drill string and a cutting end for rotation in unison with the body. The cutting end comprises at least two blades, each of the at least two blades comprising a front sidewall surface, a back sidewall surface, an inner end, an outer end, and at least one beveled portion disposed along the front sidewall surface toward the inner end of each of the at least two blades. At least one of the beveled portions comprise at least one cutting element disposed thereon that is disposed across a center point of the face of the cutting end to provide for cutting away an object disposed in a wellbore to occur across a center point of the cutting end.