Abstract: Methods are provided for making use of an apparatus for generating vibrational energy in a borehole, the apparatus utilizes a mass and a rotary source for suspending the mass in a borehole or in casing in a borehole or in an instrument housing that may be positioned in an opened or cased borehole arranged to cause frictional contact with the surface of the rotating mass, the mass being rotatable about is rotational axis in one direction to cause it to backward whirl in the opposite direction, the centrifugal force of the whirling mass serving to generate vibrational energy that is used to obtain geophysical information as to the structure of the earth surrounding and adjacent to the borehole and for enhancing cementing and production enhancing techniques in oil or gas wells.

Abstract: Methods are provided for making use of an apparatus for generating vibrational energy in a borehole, the apparatus utilizes a mass and a rotary source for suspending the mass in a borehole or in casing in a borehole or in an instrument housing that may be positioned in an opened or cased borehole arranged to cause frictional contact with the surface of the rotating mass, the mass being rotatable about is rotational axis in one direction to cause it to backward whirl in the opposite direction, the centrifugal force of the whirling mass serving to generate vibrational energy that is used to obtain geophysical information as to the structure of the earth surrounding and adjacent to the borehole and for enhancing cementing and production enhancing techniques in oil or gas wells.

Abstract: Methods are provided for making use of an apparatus for generating vibrational energy in a borehole, the apparatus utilizes a mass and a rotary source for suspending the mass in a borehole or in casing in a borehole or in an instrument housing that may be positioned in an opened or cased borehole arranged to cause frictional contact with the surface of the rotating mass, the mass being rotatable about is rotational axis in one direction to cause it to backward whirl in the opposite direction, the centrifugal force of the whirling mass serving to generate vibrational energy that is used to obtain geophysical information as to the structure of the earth surrounding and adjacent to the borehole and for enhancing cementing and production enhancing techniques in oil or gas wells.

Abstract: An apparatus for generating vibrational energy in a borehole including an elongated mass having a surface of diameter less than the borehole, a rotary source for suspending the cylindrical mass in a borehole and a system to cause frictional contact between the surface of the mass and the borehole wall, the cylindrical mass being rotatable about its rotational axis in one direction to cause the mass to backward whirl in the opposite direction within the borehole, the cylindrical force of the whirling mass serving to generate vibrational energy in the borehole.

Abstract: A downhole seismic energy source for use in generating a seismic signal in a borehole including an elongated mass having a generally cylindrical surface of diameter less than the borehole, an actuator suspending the cylindrical mass in the borehole wherein the cylindrical surface thereof is in frictional contact with the borehole wall, the cylindrical mass being rotatable about its rotational axis to cause the mass to whirl within the borehole in the direction opposite the direction of the rotation of the mass, the mass cylindrical force serving to create a seismic energy signal.

Abstract: A vibration dampening assembly, such as a dynamic balancing apparatus, is connected to a drill bit, a downhole motor or drillstring to exert a variable force to counteract vibration inducing forces. The dynamic balancing apparatus includes a support body which supports a plurality of freely movable masses so that the masses move to a position for opposing an imbalance force which rotates with, and at the same speed as, the drill bit, downhole motor or drillstring.

Abstract: To divert sufficient fluid flow through an unsealed bearing section of a downhole drilling motor, a flow control apparatus is provided for insertion between the power section of the motor and the bottom of a drill bit which is to be turned by the motor. The flow control apparatus includes a variable flow channel having a selectable effective cross-sectional area preferably embodied by a valve. A selected effective cross-sectional area is chosen by a control mechanism, such as a snap ring or a spring used to control the position of a valve member of the valve in response to different flow rates of fluid pumped through the valve depending upon whether the drill bit is on-bottom or off-bottom. In one embodiment the apparatus is incorporated within the interior of a drill bit which has angled flow channels to direct flushing fluid flow to side wall locations where reaming occurs. Flow through these outlets is controlled by positioning of the valve member.

Abstract: To stabilize a drill string and to reduce or prevent wellbore deviation in directional drilling, weight rods by which weight is to be applied to drill bit are maintained free-standing and under compression within a drill string while the drill string itself is maintained in tension to limit or prevent lateral deviation of the weight rods in compression. Weight provided by the weight rods is transferred to the drill bit through a load transfer member in compression connected between the drill string and the drill bit.

Abstract: A downhole drilling apparatus for use with an undergauge drill bit comprises a downhole drilling motor which includes a housing and means for rotating the drill bit relative to the housing about an axis of rotation. The apparatus also comprises stabilizers connected to the housing for stabilizing the drill bit, and it further comprises cutters connected to the housing for cutting a borehole wall created by passage of the drill bit, wherein the cutters extend radially outwardly relative to the axis of rotation to a greater extent than does the drill bit. A drilling assembly including such a drilling apparatus and a method of drilling a substantially vertical borehole in an earthen formation utilizing such an apparatus are also disclosed.

Abstract: A method for modeling and building drill bits. An array of spatial coordinates representative of selected surface points on a drill bit body and on cutters mounted thereon is created. The array is used to calculate the position of each cutting surface relative to the longitudinal axis of the bit body. A vertical reference plane which contains the longitudinal axis of the bit body is established. Coordinates defining each cutter surface are rotated about the longitudinal axis of the bit body and projected onto the reference plane thereby defining a projected cutting surface profile. In manufacturing a drill bit, a preselected number of cutters are mounted on the bit body. A model of the geometry of the bit body is generated as above described. Thereafter, the imbalance force which would occur in the bit body under defined drilling parameters is calculated.