Patent Publication Number: US-9890602-B2

Title: Well runner

Description:
PRIORITY APPLICATIONS 
     This application is a U.S. National Stage Filing under U.S.C. §371 from International Application No. PTC/NO2012/050235, filed on 26 Nov. 2012, and published as WO/2014/081305 on 30 May 2014; which application and publication are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The invention relates to a well runner for use in pipelines and boreholes for the production of oil and gas. 
     BACKGROUND OF THE INVENTION 
     In pipelines and boreholes having lengths of several km there is usually a need for conveying down different equipment and tools and/or collecting or acquisition of measured data or samples, etc. For those purposes pulling tools or well tractors having different embodiments are being used, wherein some have wheels or chains providing for axial rolling of the pulling tool or well tractor on the pipe or borehole wall. The roller(s) or the chain(s) is(are) being pressed against the pipe or borehole wall with a force that is sufficient for achieving the desired axial propulsive force in a number of varying frictional conditions. The power supply is commonly effected via a cable connection to the surface. 
     Most known pulling tools or well tractors utilize electric/hydraulic operation(s). This means that an electric motor drives a hydraulic pump, which again supplies power to the hydraulic motor(s) in the driving wheel(s). Such a system will be technically complex, and consequently low efficiency will be achieved. With a limited supply of power through long cable(s), the traction or propulsion force will be substantially limited. In several operations great tractive or propulsive force or power is desirable. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a substantially higher performance and/or efficiency for the well runner. 
     Another object of the invention is to meet, in a simple and robust way, the functional requirements for the well runner regarding handling of restrictions and sharp curvatures or other obstacles without getting stuck. 
     Yet another object of the invention is to overcome some of the disadvantages and drawbacks of the known prior art. 
     According to one aspect of the invention this is achieved with the help of a borehole or well tractor or runner as described and specified in this publication. 
     According to another aspect of the invention this is achieved with the help of a drive module for a well runner as described and specified in this publication. 
     A drive module for a borehole or well tractor or runner comprises a drive module housing and a hydraulically actuated and pivoting drive arm comprising an arm housing and a drive wheel arranged thereto, wherein the drive wheel is driven by a motor mounted outside the drive arm housing and arranged along and parallel with the drive arm in resting position and onto or into the drive module wall for the cavity arranged or provided for the drive arm, and wherein the drive wheel is drivingly connected to the motor via a drive line arrangement, i.e. via a belt or chain drive arrangement and further via an angular gear or gearing arrangement mounted outside the drive arm housing. 
     A borehole or well tractor or runner comprises at least one of said drive modules. 
     The angular gear or gearing arrangement of the drive line arrangement can be a bevel gear combined with a dual chain or belt drive arrangement. Alternatively, the drive line arrangement can comprise a bevel gear combined with a planetary gear and a single chain or belt drive arrangement. 
     The main features of this invention are given in the independent claims. Additional features of the present invention are given in the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects of the invention are apparent from and will be further elucidated, by way of example(s), with reference to the drawings, wherein: 
         FIG. 1  shows in perspective one embodiment of a borehole or well tractor or runner according to the present invention; 
         FIG. 2A-2C  show different views and a cross section of an embodiment of a drive module for the borehole or well tractor or runner according to the present invention; 
         FIG. 3A-3D  show different views of important drive line elements of the drive module for the borehole or well tractor or runner according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In the present invention the propulsion effect is provided without use of hydraulics. Thereby a substantially higher performance is achieved for the borehole or well tractor or runner. 
     A borehole or well tractor or runner should be designed to be able to negotiate different restrictions, sharp curvatures and/or other obstacles without getting stuck. In order to achieve these important or required functions, a solution has been provided in the present invention, thus making it possible to meet said functional requirements in a simple and robust way. 
       FIG. 1  shows, in perspective, one embodiment of a borehole or well tractor or runner  1  according to the present invention. The well runner  1  comprises or is being divided in at least two units, wherein the well runner  1 , and in particular each of its units, is provided with an outer housing  20 . In this embodiment the well runner  1  is shown comprising two drive units  10 ′,  10 ″, one hydraulics unit  14 , one electronic modules unit  15 , a near or top side or end module unit  30  and a far or bottom side or end module unit  13 , wherein the near or top side or end of the well runner  1  can be defined as the well runner  1  end being closer to the place where the well runner  1  entered the borehole or pipeline, than the other well runner  1  end, which is being defined as the far or bottom side or end of said well runner  1 . 
     A tension sub (not shown) for cable tension monitoring can be positioned at the top end of well runner  1 . This tension sub can be used to prevent the well runner  1  from running over the cable  26  during reverse operation. The tension sub can presumably be arranged or placed in the cable fastening point at top of the well runner  1 , for example in the top side module unit, also called as (upper) UMT (user module top)  30 . 
     Centralization module(s) can presumably be required in order to stabilize the well runner  1  at the center of a casing or pipe, and can presumably be arranged or placed as or in the top side module unit or UTM unit  30 . With this construction/design it can be achieved that the well runner  1  should always be kept centered within a pipe or borehole or casing. This is a condition for allowing efficient positioning of equipment and/or operation of measuring tool(s), etc. 
     Each drive unit  10 ′,  10 ″ can comprise at least one drive module  11 ′,  12 ′,  11 ″,  12 ″, and in this embodiment of the well runner  1  each drive unit  10 ′, respectively  10 ″, comprises two drive modules  11 ′,  12 ′, respectively  11 ″,  12 ″. There can be for example up to four drive modules  11 ′,  12 ′,  11 ″,  12 ″ having drive arms in one drive unit or body  10 ′,  10 ″. Higher number (than four) of drive modules in one drive unit can also be possible. Higher number (than two) of drive units in the well runner can be possible too. Each drive unit  10 ′,  10 ″ can further comprise a motor controller or MC module (not shown). 
     One desired design of the well runner  1  comprises two drive units  10 ′, respectively  10 ″ having two drive modules  11 ′,  12 ′, respectively  11 ″,  12 ″, each with 90°, 180° and 270° degrees angle of one arm relative to other arms viewed in a section perpendicular to the longitudinal axis of the well runner  1 . Of course, other suitable angles should be possible (e.g. 120 and 240 degrees offset from each other, etc.). 
     The electronic modules unit  15  can comprise at least one of: a power supply module, a telemetry module and a tractor or runner controller module. 
     The hydraulics unit  14  can be used for e.g. operating or actuating a hydraulic actuator, e.g. a hydraulic cylinder, providing for manipulating a drive wheel/arm of a drive module  11 ′,  12 ′,  11 ″,  12 ″. The hydraulics unit  14  can comprise a pressure compensation chamber against the well and a volume expansion chamber. Moreover, it comprises an electric motor and a pump as well as a valve system and (pressure) sensor(s) in order to operate and/or control the hydraulic actuation of each drive module arm  16 . The motor, pump and valve system are being controlled e.g. electronically by a controller (unit) in the electrical or electronic module  15 . 
     The far or bottom side or end module unit  13  can be used as an interface for payload module(s) that can be connected or coupled thereto, wherein a payload module is e.g., and not limited only to, a tool or equipment that is to be carried and operated in the well or pipe, such as e.g. anchors, actuators, mills/stampers, logging equipment, etc. 
     Several control systems and additional modules can be integrated in or connected to the well runner  1 , when or if needed or necessary, in order to e.g. monitor different/various functions and/or operations of the well runner  1  and/or its units or elements. 
     The module and/or unit configuration shown in  FIG. 1  is just an example of such, but however other module/unit configurations of the well runner  1  may be just as suitable. 
       FIG. 2A-2C  show different views and a cross section of an embodiment of a drive module  11 ′,  12 ′,  11 ″,  12 ″ for the borehole or well tractor or runner  1  according to the present invention. 
     Every drive module  11 ′,  12 ′,  11 ″,  12 ″ has individual propulsion with a determined maximum pulling or tractive force or power, based on the motor capacity and the friction between the drive wheel  17  and the pipe or casing wall (not shown). Hence, configuring a predetermined number of drive units  10 ′,  10 ″, respectively drive modules  11 ′,  12 ′,  11 ″,  12 ″, in series can provide the required or desired total propulsion force capacity for the well runner  1 . 
     The drive module  11 ′,  12 ′,  11 ″,  12 ″ can move in both directions, wherein the drive wheel  17  moves in both directions of rotation with identical capacity and/or speed. Every drive module  11 ′,  12 ′,  11 ″,  12 ″ comprises a motor  21 , e.g. an electrical motor, a drive wheel  17  and a drive line arrangement  22 ,  23  between the motor  21  and the drive wheel  17 . The drive wheel  17  and some parts of the drive line arrangement  22 ,  23  are installed on a drive arm  16  in order to enable variable distance relative to the rest of the drive module  11 ′,  12 ′,  11 ″,  12 ″, respectively the well runner  1 , in order to reach the pipe or borehole or casing wall in which it is run. 
     The position of the drive wheel  17 /arm  16  may be manipulated using an adjustable pressure hydraulic actuator  18 , e.g. adjustable pressure hydraulic cylinder. 
     Each arm  16  can be individually activated or deactivated/returned to its closed or resting position, if needed (e.g. in case of malfunction in the drive line arrangement  22 ,  23  in a drive module  11 ′,  12 ′,  11 ″,  12 ″). 
     The arm&#39;s  16  pivoting linkages and the fastening point for the hydraulic cylinder&#39;s  18  position have a geometry that enables a relatively linear relation between the contact force from the drive wheel  17  on the casing or pipe and the corresponding hydraulic cylinder  18  pressure, valid for the entire reach of the drive wheel  17  relative to the drive module  11 ′,  12 ′,  11 ″,  12 ″ (which simplifies the control need for hydraulic pressure). 
     The drive wheel&#39;s  17  contact force on or against or towards the casing or pipe or borehole can then be adjusted in order to obtain a required or desired friction, simply by manipulating the cylinder  18  pressure. Further, a very simple traction control arrangement or system may be implemented based on obtaining the required or desired friction by defining the cylinder  18  pressure as a function of the operator-set pull or push force for the well tractor. A computing unit may be connected in order to auto-matically regulate the hydraulic pressure to the cylinder  18  based on the operator&#39;s pull or push force commands. 
     One possible design has a spring return function (clock spring) exerting continuous force on the arm  16 , wherein the drive arm  16  can be hinged to a single acting hydraulic actuator  18  and a rotational retraction spring (not shown). An alternate design could be utilizing a double or dual acting hydraulic actuator  18 , e.g. double or dual motion hydraulic cylinder, providing for the hydraulic operation of the drive arm  16 . Both designs provide for returning the arm  16 /drive wheel  17  in closed or resting position. 
     In order to control the drive wheel&#39;s  17  rotation, speed and position, every drive module  11 ′,  12 ′,  11 ″,  12 ″ can also comprise and/or utilize possible or required control components, means and/or systems, that all or partially can be arranged e.g. in the motor controller module. 
     Each drive wheel  17  and/or motor  21  can be controlled and operated independently. Despite that each drive module  11 ′,  12 ′,  11 ″,  12 ″ is mechanically independent of the other drive module(s), it can be possible or necessary to connect them together or make them communicate together in order to synchronize rotation, speed, position, torque, force or other characteristics for one drive wheel  17  with all the other drive wheels  17 , for all installed drive modules  11 ′,  12 ′,  11 ″,  12 ″. 
     With reference numeral  40  in  FIGS. 2A and 2B  a cover  40  for the motor  21  and/or the drive line  22  being arranged on the housing  20  is shown. 
     A cavity  27  arranged or provided for the drive arm  16  and the drive wheel  17 , when being in a resting position and being along and parallel with the motor  21  and the drive line  22  hidden by the cover  40 , is shown on  FIGS. 2A and 2C . 
       FIG. 3A-3D  show different views of important drive line elements or components of the drive module  11 ′,  12 ′,  11 ″,  12 ″ for the borehole or well tractor or runner  1  according to the present invention. 
     A detailed description with respect to the drive line arrangement  22 ,  23  and the position of its components or elements will be given below. 
     The motor  21  is arranged or installed outside the arm  16 . In order to keep the longitudinal length of the drive module  11 ′,  12 ′,  11 ″,  12 ″ as short as possible, the motor  21  and the drive line  22  are installed parallel to the arm  16  in resting position ( FIG. 3A ). 
     The angular or bevel gear or gearing arrangement  22  can be an individual module in the drive line arrangement  22 ,  23 . 
     The extending axle on or of the angular gear  22  has an identical center axis as the rotational (or tilt) axis of the (drive) arm  18 . 
     In one possible design the motor  21  is connected to a drive wheel  17  with an angular gear  22  and two chains or belts  24 ′,  24 ″ connected in series. An alternative design could be replacing one of the chains or belts  24  with a planetary gear (not shown), on the same axle as the extending axle on the angular gear  22 , in order to obtain desired gear ratio. 
     The shown chain or belt drive  23  has very low sensitivity to tolerances of the positioning of independent components (chain/belt parallelism, etc.) compared to e.g. gears, hence providing a robust system. 
     The motor  21 , angular gear  22  and belt or chain housing (arm housing)  16  may all have individual and separate lubrication to prevent spreading pollution between them. All chambers can be pressure equalized with the surroundings by external pressure equalization chambers. 
     The chain/belt drive  23  comprises, as shown in  FIG. 3A-3D , two chains or belts  24 ′,  24 ″ connected in series, where the shared axle for both drives are axially displaceable, such as shown chain tightening mechanism  25  can be utilized to tighten both chains or belts  24 ′,  24 ″. 
     The chain tightening mechanism  25  can also serve as a damper in the drive line arrangement  22 ,  23 , so that impulses/shocks from the drive wheel  17  will be dampened before reaching the angular gear  22  and the motor  21 . 
     The arm  16  with drive wheel  17  is being activated or rotated outwards from closed or resting position towards at least one expanded position by use of the hydraulic cylinder  18 . 
     In one possible design the arm  16  can have a profile/contact surface  19  (on  FIG. 2B ) serving as a rotational stopper  19  for the arm  16  at maximal expansion/torsion of arm  16 . The profile  19  of the arm  16  comes in contact with a corresponding profile on the drive module&#39;s  11 ′,  12 ′,  11 ″,  12 ″ body. The purpose of this stopper  19  is to simplify the hydraulic cylinder  18 , so that the cylinder  18  itself will not need a stopper for securing its end outstretching or expansion, something that would require sufficient space. Thus the stopping or the end/outstretched position of the arm  16  is provided rather by the outstretching or swinging limitation of the arm  16  itself. 
     The geometric relations between the rotational axis for the arm  16  and the attachment points for the hydraulic cylinder  18  are chosen to as best as possible, so that at a fixed hydraulic pressure the force outwards on the drive wheel  17  will be kept constant across the entire range of the drive wheel  17  relative to the drive module  11 ′,  12 ′,  11 ″,  12 ″ (which simplifies the control need for hydraulic pressure). 
     The hydraulic system or cylinder  18  for arm  16  activation and/or control is made to enable deactivating (pulling in) of each arm  16  (e.g. one or more) independently without any need for deactivation of the other arms  16 . Arm deactivation can be done, if e.g. a drive line  22 ,  23  problem for an arm is registered, or also if e.g. a special (changed) centralization of the well runner  1  in the well or pipe is desired or required. Such a function will be of significance when entering y-sections in/of the well or pipe. In a y-section a well tractor or runner should be able to change centering in order to enter or go further. 
     The hydraulic system or cylinder  18  for controlling the arm  16  activation and control can also control the arm&#39;s  16  (hence also the drive wheel&#39;s  17 ) force outward on the well or pipe wall, hence optimizing/adjusting this according to the present or current conditions (propulsion force, casing or pipe wall condition, drive wheel condition, etc.). 
     The motor  21  can be supplied with power through cable line  26  or a cable element  26 ′ ( FIG. 2C ) of the cable line  26 . The cable (line) or wireline  26  provides for supply of electric power and control and/or feedback signals to the running unit or tractor/well runner. The cable  26  is in addition used for pulling the running unit out of the well under normal conditions. Such wirelines (e-lines) come from many manufacturers and with various constructions and/or sizes having thus varying strength and electrical capacity (depending on the number of conductors and/or the cross-section of the conductors). Most challenging is a cable with a single conductor when communication must be provided over the electrical power supply for the operation of the running unit or well tractor/runner. In addition, there is of course a limitation on the power transmission capacity of a cable due to the conductor cross-section and/or length of the cable and the fact that there are limitations on the permitted voltage that is to be applied to the cable. That is why the efficiency of the well tractor or runner has a great practical significance. With the present low effective tractors, it is often necessary to cut or reduce the wireline length in order to be able to transfer the required electrical power, e.g. if there is an extra cable length to be cut or removed in accordance with the job or operational depth, where the problem will consequently be that a costly wireline or cable (line) has been damaged. This can be avoided by the higher efficiency of the well tractor or runner according to the present invention. It is possible to go deeper and use the capacity of the well runner or tractor according to the present invention without being constrained by the power transmission capacity. 
     The well runner  1  and its units or modules can have an elongated, cylindrical form. 
     Several steps of gearing ratio can be provided by the drive line arrangement  22 ,  23 . 
     Additional modifications, alterations and adaptations of the present invention will suggest themselves to those skilled in the art without departing from the scope of the invention as expressed and stated in the following patent claims.