Borehole apparatus for investigating subsurface earth formations including a plurality of pad members and means for regulating the bearing pressure thereof

Abstract

.Iadd. A borehole investigating apparatus includes, an elongated support member, a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line and a second pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line at right angles to the given line for the first pair. The apparatus further includes first and second pad extending means for respectively moving the pad members of the first and second pairs away from the support member and against the borehole wall. The apparatus further includes primary driving means and a force dividing mechanism coupling this primary driving means to the first and second pad extending means for enabling unequal lateral extension of the pad members of the different pairs..Iaddend.

What is claimed is: 
     
       1. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line; a second pair of wall-engaging pad members individually disposed on opposite sides of the support member along a line at right angles to the given line for the first pair; a first set of arm means coupling the first pair of pad members to the support member for enabling lateral movement of these pad members with respect to the support member; a second set of arm means coupling the second pair of pad members to the support member for enabling lateral movement of these pad members with respect to the support member; linkage means coupled to the support member and to the pad members for preventing longitudinal movement of the pad members with respect to the support member whenever the pad members undergo lateral movement with respect thereto; a primary driving member; a rocker member pivotally connected intermediate its extremities to the primary driving member; a pair of secondary driving mechanisms coupling the two extremities of the rocker member to different ones of the two sets of arm means; a rigid base member; elastic means acting between the base member and the primary driving member for applying a driving force to the primary driving member; means for adjusting the position of the base member with respect to the primary driving member for adjusting the driving force applied thereto; motor means for selectively actuating the position adjusting means; first and second signalling means for providing first and second signals representative of the magnitudes of lateral separation between the two pad members of each pair; third signalling means for providing a third signal representative of the position of the base member; means responsive to the first, second and third signals for providing an indication of the bearing pressure of the pad members on the wall of the borehole; and means for controlling the motor means for adjusting the pad member bearing pressure. 
     
     
       2. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line; a second pair of wall-engaging pad members individually disposed on opposite sides of the support member along a line at right angles to the given line for the first pair; a pair of sliding members mounted on the support member for providing longitudinal movement with respect thereto; a first set of arm members pivotally coupled to one of the sliding members and to the first pair of pad members for enabling lateral movement of these pad members with respect to the support member; a second set of arm members pivotally coupled to the other of the sliding members and to the second pair of pad members for enabling lateral movement of these pad members with respect to the support member; linkage means couples to the support member and to the pad members for preventing longitudinal movement of the pad members with respect to the support member whenever the pad members undergo lateral movement with respect thereto; a primary driving member; a rocker member pivotally connected intermediate its extremities to the primary driving member; a pair of secondary driving mechanisms coupling the two extremities of the rocker member to different ones of the two sets of arm members; a rigid base member; elastic means acting between the base member and the primary driving member for applying a driving force to the primary driving member; means for adjusting the position of the base member with respect to the primary driving member for adjusting the driving force applied thereto; motor means for selectively actuating the position adjusting means; first and second signalling means for providing first and second signals representative of the magnitudes of lateral separation between the two pad members of each pair; third signalling means for providing a third signal representative of the position of the base member; means responsive to the first, second and third signals for providing an indication of the bearing pressure of the pad members on the wall of the borehole; and means for controlling the motor means for adjusting the pad member bearing pressure. 
     
     
       3. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line; a second pair of wall-engaging pad members individually disposed on opposite sides of the support member along a line at right angles to the given line for the first pair; sliding members movably mounted on each of the pad members for providing longitudinal movement of the sliding members with respect to the support member; a first set of arm members pivotally coupled to the support member and to the sliding members on the first pair of pad members for enabling lateral movement of these pad members with respect to the support member; a second set of arm members pivotally coupled to the support member and to the sliding members on the second pair of pad members for enabling lateral movement of these pad members with respect to the support member; linkage means coupled to the support member and to the pad members for preventing longitudinal movement of the pad members with respect to the support member whenever the pad members undergo lateral movement with respect thereto; a primary driving member; a rocker member pivotally connected intermediate its extremities to the primary driving member; a pair of secondary driving mechanisms coupling the two extremities of the rocker member to different ones of the two sets of arm members; a rigid base member; elastic means acting between the base member and the primary driving member for applying a driving force to the primary driving member; means for adjusting the position of the base member with respect to the primary driving member for adjusting the driving force applied thereto; motor means for selectively actuating the position adjusting means; first and second signalling means for providing first and second signals representative of the magnitudes of lateral separation between the two pad members of each pair; third signalling means for providing a third signal representative of the position of the base member; means responsive to the first, second and third signals for providing an indication of the bearing pressure of the pad members on the wall of the borehole; and means for controlling the motor means for adjusting the pad member bearing pressure. 
     
     
       4. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line; a second pair of wall-engaging pad members individually disposed on opposite sides of the support member along a line at right angles to the given line for the first pair; a first set of arm means coupling the first pair of pad members to the support member for enabling lateral movement of these pad members with respect to the support member; a second set of arm means coupling the second pair of pad members to the support member for enabling lateral movement of these pad members with respect to the support member; linkage means coupled to the support member and to the pad members for preventing longitudinal movement of the pad members with respect to the support member whenever the pad members undergo lateral movement with respect thereto; a primary driving member; a rocker member pivotally connected intermediate its extremities to the primary driving member; a pair of secondary driving mechanisms coupling the two extremities of the rocker member to different ones of the two sets of arm means; a rigid base member; a coil spring acting between the base member and the primary driving member for applying a driving force to the primary driving member; worm gear means for adjusting the position of the base member with respect to the primary driving member for adjusting the driving force applied thereto; an electric motor for selectively actuating the worm gear means; first and second signalling means for providing first and second electrical signals representative of the magnitudes of lateral separation between the two pad members of each pair; third signalling means for providing a third electrical signal representative of the position of the base member; electrical analog computer means responsive to the first, second and third signals for providing an electrical signal representative of the bearing pressure of the pad members on the wall of the borehole; and feedback control circuit means responsive to the bearing pressure signal for controlling the electric motor for automatically regulating the pad member bearing pressure. 
     
     
       5. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elonagted support member adapted for longitudinal movement through a borehole; a plurality of wall-engaging members; at least one arm member individually coupling each of the different wall-engaging members to the support member, slide members coupled to said support member and upon which said wall-engaging members are slidably mounted, said slide members being arranged to move longitudinally with respect to said support member, and means for preventing longitudinal movement of the wall-engaging members with respect to the support member. 
     
     
       6. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a plurality of wall-engaging members; at least one arm member individually coupling each of the different wall-engaging members to the support member, the connection between the arm member and the wall-engaging member being a fixed pivotal connection; a base member for slidably supporting each of said wall-engaging members; means pivotally connecting said base members with said support member and arranged to permit longitudinal movement of said base members relative to said support member; means for preventing longitudinal movement of the wall-engaging members with respect to the support member; and means for applying separate driving forces to the different wall-engaging members for enabling unequal lateral extension of the different wall-engaging members. 
     
     
       7. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a plurality of wall-engaging members; a plurality of sliding members movably mounted on the support member for providing longitudinal movement of the sliding members with respect to the support member; a plurality of arm members each being individually pivotally coupled to one of the sliding members and to one of the wall-engaging members for enabling movement of the wall-engaging members away from the support member; a plurality of linkage means each being individually coupled to the support member and to one of the wall-engaging members for preventing longitudinal movement of the wall-engaging members with respect to the support member; and means for applying separate driving forces to the different arm members for enabling unequal lateral extension of the different wall-engaging members. 
     
     
       8. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a plurality of wall-engaging members; a sliding member movably mounted on each of the wall-engaging members each being for providing longitudinal movement of the sliding members with respect to the wall-engaging members; a plurality of arm members each being individually pivotally coupled to the support member and to one of the sliding members for enabling movement of the wall-engaging members away from the support member; a plurality of linkage means each being individually coupled to the support member and to one of the wall-engaging members for preventing longitudinal movement of the wall-engaging members with respect to the support member; and means for applying separate driving forces to the different arm members for enabling unequal lateral extension of the different wall-engaging members. 
     
     
       9. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a plurality of wall-engaging members; a plurality of sliding members movably mounted on the support member for providing longitudinal movement of the sliding members with respect to the support member; a plurality of primary arm members each of which is individually pivotally coupled to one of the sliding members and to one of the wall-engaging members for enabling movement of the wall-engaging members away from the support member; a plurality of secondary arm members each of which is individually pivotally coupled to one of the sliding members and to one of the wall-engaging members at a predetermined distance from the corresponding primary arm member; a plurality of linkage members each of which is individually coupled between the support member and the midpoint of one of the secondary arm members for preventing longitudinal movement of the wall-engaging members with respect to the support member; and means for applying separate driving forces to the different primary arm members for enabling unequal lateral extension of the different wall-engaging members. 
     
     
       10. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a plurality of wall-engaging members; a sliding member movably mounted on each of the wall-engaging members for providing longitudinal movement of the sliding member with respect to the wall-engaging member; a plurality of primary arm members each of which is individually pivotally coupled to the support member and to one of the sliding members for enabling movement of the wall-engaging members away from the support member; a plurality of secondary arm members each of which is individually pivotally coupled to the support member and to one of the wall-engaging members; a plurality of linkage members each of which is individually coupled between the support member and the midpoint of one of the secondary arm members for preventing longitudinal movement of the wall-engaging members with respect to the support member; and means for applying separate driving forces to the different primary arm members for enabling unequal lateral extension of the different wall-engaging members. 
     
     
       11. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a wall-engaging member; a movable sliding member connected by link means between the support member and the wall-engaging member for providing longitudinal movement of the sliding member with respect to the support member; said link means including an arm member pivotally coupled to the sliding member for enabling lateral movement of the wall-engaging member away from the support member; said wall-engaging member being slidably mounted on said movable sliding member for providing relative longitudinal movement therebetween; linkage means coupled to the support member and to the wall-engaging member for preventing longitudinal movement of the wall-engaging member with respect to the support member; and means for applying a driving force to the arm member for causing lateral extension of the wall-engaging member. 
     
     
       12. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for movement through a borehole; a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line; a second pair of wall-engaging pad members individually disposed on opposite sides of the support member along a line at right angles to the given line for the first pair; first pad extending means for moving the pad members of the first pair away from the support member and against the borehole wall; second pad extending means for moving the pad members of the second pair away from the support member and against the borehole wall; primary driving means; a force dividing mechanism coupling the primary driving means to the first and second pad extending means for enabling unequal lateral extension of the pad members of the different pairs; means for applying a driving force to the primary driving means; means for providing an indication of the bearing pressure of the pad members on the borehole wall; and means for adjusting the driving force applied to the primary driving means thereby to enable regulation of the bearing pressure. 
     
     
       13. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for movement through a borehole; a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line; a secod pair of wall-engaging pad members individually disposed on opposite sides of the support member along a line at right angles to the given line for the first pair; first pad extending means for moving the pad members of the first pair away from the support member and against the borehole wall; second pad extending means for moving the pad members of the second pair away from the support member and against the borehole wall; primary driving means; a force dividing mechanism coupling the primary driving means to the first and second pad extending means for enabling unequal lateral extension of the pad members of the different pairs; and means for applying a driving force to the primary driving means. 
     
     
       14. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for movement through a borehole; a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line; a second pair of wall-engaging pad members individually disposed on opposite sides of the support member along a line at right angles to the given line for the first pair; first pad extending means for moving the pad members of the first pair away from the support member and against the borehole wall; second pad extending means for moving the pad members of the second pair away from the support member and against the borehole wall; a primary driving member; a rocker member pivotally connected intermediate its extremities to the primary driving member; a pair of secondary driving mechanisms coupling the two extremities of the rocker member to different ones of the first and second pad extending means; and means for applying a driving force to the primary driving member. 
     
     
       15. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for movement through a borehole; a wall-engaging member; means for driving the wall-engaging member away from the support member and against the wall of the borehole; means for providing an indication of the bearing pressure of the wall engaging member on the borehole wall; and means for adjusting the driving force applied to the wall-engaging member thereby to enable regulation of the bearing pressure. 
     
     
       16. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for movement through a borehole; a wall-engaging member; means for driving the wall-engaging member away from the support member and against the wall of the borehole; means coupled to the driving means for providing an electrical signal representative of the bearing pressure of the wall-engaging member on the borehole wall; and feedback control circuit means responsive to the bearing pressure signal for adjusting the driving force applied to the wall-engaging member for automatically regulating the bearing pressure of the wall-engaging member. 
     
     
       17. In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for movement through a borehole; a wall-engaging member; arm means coupling the wall-engaging member to the support member; means for transmitting a driving force to the arm means for enabling extension thereof; a base member; spring means acting between the base member and the force transmitting means for applying a driving force to such transmitting means; means for adjusting the position of the base member; electric motor means for selectively actuating the position adjusting means; means for providing an electrical signal representative of the magnitude of compression of the spring means; and feedback control circuit means responsive to the electrical signal for controlling the electric motor for automatically regulating the compression of the spring means and, hence, the bearing pressure of the wall-engaging member. 
     
     
       18. In an apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member adapted for longitudinal movement through a borehole; a plurality of wall-engaging members; slide members upon which said wall-engaging members are slidably mounted, said slide members being coupled to said support member and arranged to move longitudinally with respect to said support member and said wall-engaging members; a plurality of arm members coupling different wall-engaging members to the support member; and linkage means connected between said wall-engaging members and said support member, said linkage means being arranged for permitting transverse movement of said wall-engaging members with respect to said support member while preventing longitudinal movement therebetween. 
     
     
       19. The apparatus of claim 18 and further including means for applying separate driving forces to different wall-engaging members for enabling unequal lateral extension of different wall-engaging members. 
     
     
       20. The apparatus of claim 18 wherein said linkage means includes a linkage member which is one-half the length of said arm members and connected to the midpoint of one of said arm members. 
     
     
       21. The apparatus of claim 19 and further including means for adjusting the driving forces applied to the wall-engaging members to automatically regulate the force with which said well-engaging member is driven against a borehole wall. .Iadd. 
     
     
       22.  In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member having a longitudinal axis and adapted for longitudinal movement through a borehole;   a plurality of wall-engaging members having wall-engaging faces and arranged with a first pair of the wall-engaging members individually disposed on laterally -opposite sides of the support member along a first given line in a lateral plane and a second pair of the wall-engaging members individually disposed on laterally-opposite sides of the support member along a second given line at right angles to the first given line and in the same lateral plane;   a plurality of sliding members movably mounted on the support member for providing longitudinal movement of the sliding members with respect to the support member;   a plurality of primary arm members disposed in two pairs, each primary arm member being individually pivotally coupled to one of the sliding members and to one of the wall-engaging members for enabling movement of the wall-engaging members away from the support member without relative longitudinal movement;   a plurality of linkage means disposed in two pairs, each linkage means being individually pivotally coupled to the support member at a first pivot point providing a fixed reference in the lateral plane and to one of the wall-engaging members at a second pivot point in the same lateral plane, and including an arm member pivotally coupled between the second pivot point and a third pivot point in longitudinal alignment with the first pivot point, the first, second and third pivot points defining a right triangle having such arm member as its hypotenuse, and a linkage member pivotally connected between such arm member and the first pivot point as the median of the hypotenuse for preventing longitudinal movement of the wall-engaging members with respect to the support member while the arm members cooperate to keep the faces of the wall-engaging members substantially parallel to the longitudinal axis of the support member; and   means for applying separate driving forces to the different pairs of respectively coupled arm members, linkage means and wall-engaging members for enabling unequal lateral extension of the different pairs of wall-engaging members. .Iaddend. .Iadd.   
     
     
       23.  In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member having a longitudinal axis and adapted for longitudinal movement through a borehole;   a plurality of wall-engaging members having wall-engaging faces and arranged with a first pair of wall-engaging members individually disposed on laterally-opposite sides of the support member along a first given line in a lateral plane and a second pair of the wall-engaging members individually disposed on laterally-opposite sides of the support member along a second given line at right angles to the first given line and in the same lateral plane;   a plurality of sliding members disposed in two pairs so that a sliding member is movably mounted on each of the wall-engaging members each being for providing longitudinal movement of the sliding members with respect to the wall-engaging members in each of the respective pairs;   a plurality of arm members being individually pivotally coupled to the support member and to one of the sliding members, said arm members cooperating to keep the faces of the wall-engaging members substantially parallel to the longitudinal axis of the support member and for enabling movement of the wall-engaging members away from the support member without relative longitudinal movement;   a plurality of linkage means disposed in two pairs, each linkage means being individually pivotally coupled to the support member at a first pivot point providing a fixed reference in the lateral plane and to one of the wall-engaging members at a second pivot point in the same lateral plane, and including an arm member pivotally coupled between second pivot point and a third pivot point in longitudinal alignment with the first pivot point, the first, second and third pivot points defining a right triangle having the second arm member as its hypotenuse, and a linkage member pivotally connected between the second arm member and the first pivot point as the median of the hypotenuse for preventing longitudinal movement of the wall-engaging members with respect to the support member; and   means for applying separate driving forces to the different pairs of respectively coupled arm members, linkage means and wall-engaging members for enabling unequal lateral extension of the different pairs of wall-engaging members. .Iaddend. .Iadd.   
     
     
       24.  In apparatus for investigating earth formations traversed by a borehole, the combination comprising: an elongated support member having a longitudinal axis an adapted for movement through a borehole;   a first pair of wall-engaging pad members having wall-engaging faces and individually disposed on opposite sides of the support member along a first given line in a lateral plane;   a second pair of wall-engaging pad members having wall-engaging faces and individually disposed on opposite sides of the support member along a second given line at right angles to the first given line for the first pair of wall-engaging pad members and in the same lateral plane;   first pad extending means for moving the pad members of the first pair away from the support member and against the borehole wall;   second pad extending means for moving the pad members of the second pair away from the support member and against the borehole wall;   the pad extending means including a plurality of sliding members disposed in pairs, each sliding member being mounted for longitudinal movement with respect to the support member and a respective pad member;   a plurality of arm members, said arm members cooperating to keep the faces of the pad members substantially parallel to the longitudinal axis of the support member, each arm member having individual pivotal couplings with the support member and with one of the sliding members, one of the sliding members providing one of such pivotal couplings for each respective arm member for enabling movement of the pad members away from the support member without relative longitudinal movement; and   a plurality of linkage means disposed in two pairs, each linkage means being individually pivotally coupled to the support member at a first pivot point providing a fixed reference in the lateral plane and to one of the pad members at a second pivot point in the same lateral plane, and including an arm member pivotally coupled between the second pivot point and a third pivot point in longitudinal alignment with the first pivot point, the first, second and third pivot points defining a right triangle having such arm member as its hypotenuse, and a linkage member pivotally connected between such arm member and the first pivot point as the median of the hypotenuse for preventing longitudinal movement of the pad members with respect to the support member;   primary driving means;   a force dividing mechanism coupling the primary driving means to the first and second pad extending means for enabling unequal lateral extension of the pad members of the different pairs; and   means for applying a driving force to the primary driving means. .Iaddend. .Iadd.   
     
     
       25.  The apparatus of claim 24 wherein the pad members carry respective electrode means for formation dip measurements, electrical signaling means being associated with the respective pair of pad members for providing indications of respective borehole diameters in the directions of the first and second lines. .Iaddend.