Abstract:
Method and apparatus for collecting data. The apparatus for a motorless seismic tool includes a body; a motorless clamping mechanism connected to the body; and an anchoring arm attached to the body and the motorless clamping mechanism. The motorless clamping mechanism is configured to close or open the anchoring arm based on gravity.

Description:
BACKGROUND 
     Technical Field 
     Embodiments of the subject matter disclosed herein generally relate to an apparatus and method for a motorless seismic tool. 
     Discussion of the Background 
     A seismic tool may be a device used to conduct seismic surveys in downhole environments, such as, for example, inside of wells used for oil and gas extraction. Seismic tools may contain sensors, such as, for example, geophones. In order to function properly, a seismic tool that has been lowered into a well may need to be anchored in place with the seismic tool pressed up against the wall of the well. Several seismic tools may be connected together, top to bottom, along with other seismic survey equipment, using a cable, and lowered into a well. 
       FIG. 1  depicts an exemplary seismic tool.  FIG. 2  depicts an exemplary diagram of a seismic tool. The seismic tool  101  may include a main housing  12 , upper cable head  13 , lower cable head  14 , and anchoring arm  16 . A logging cable  15  may be connected to the upper cable head  13  at the top and the lower cable head  14  at the bottom of the seismic tool  101 . The main housing  12  may be a housing of any suitable shape and made of any suitable material for enclosing any equipment, such as, for example, sensors, motors, and other mechanical, electric, and electronic components, within the seismic tool  101 . The upper cable head  13  and the lower cable head  14  may enclose the seismic tool  101  on the top and bottom ends, respectively, and may be made of a similar material to the main housing  12  or any appropriate material. The anchoring arm  16  may be any suitable material in any suitable shape for allowing the seismic tool  101  to be lowered into a well when the anchoring arm  16  is in a closed position, and to anchor the seismic tool  101  against the wall of the well when the anchoring arm  16  is in an open position. For example, the anchoring arm  16  may be made of metal in a curved scoop shape. The anchoring arm  16  may be attached to the main housing  12  in any suitable manner to allow the anchoring arm  16  to switch between closed and open positions. The logging cable  15  may connect the seismic tool  101  to other devices, such as, for example, other seismic tools, telemetry devices, or electronic devices that allow the seismic tool  101  to transmit data to a computer. For example, the seismic tool  101  may be deployed in a string of similar seismic tools, and may be connected to other seismic tools  101  above and below through the logging cable  15 . The logging cable  15  may be made of any suitable material for supporting the weight of the seismic tools  101  as they are lowered into a well, and may also include cabling for data and power transmission. The seismic tool  101  may receive power and control commands through the logging cable  15 . 
       FIG. 3  depicts an exemplary diagram of an internal view of a seismic tool with a motor. To use the anchoring arm  16 , the seismic tool  101  may include a motor  301  within the main housing  12 . The motor  301  may be any suitable motor for use within the seismic tool  101 , such as, for example, an electric motor. Any suitable system for motion transmission may be used to allow the motor  301  to operate the anchoring arm  16 , such as, for example, interlocked gears  302 . The motor  301  may be able to move the anchoring arm  16  between closed and open positions, and may be controlled by commands received through the logging cable  15 . 
       FIGS. 4 a  and 4 b    depict an exemplary seismic tool in use within a well. A well  401  may be, for example, a well dug to allow the extraction of oil from oil deposits within the earth. The well  401  may be straight, or may have curved sections, and may have a wall  402 , which may be, for example, steel in a tubular shape to keep the earth from filling in the well  401 . The seismic tool  101  may be lowered into the well  401  using the logging cable  15 . While the seismic tool  101  is being lowered into the well  401  the anchoring arm  16  may be closed, as depicted in  FIG. 4 a   . When the seismic tool  101  has reached a desired position within the well  401  the anchoring arm  16  may be opened by the motor  301 . The anchoring arm  16  may open until it has anchored the seismic tool  101  within the well  401 , with the main housing  102  and the anchoring arm  16  pressing against the wall  402  of the well  401 . 
     The motor  301  used to operate the anchoring arm  16  may be expensive, heavy, and susceptible to malfunction within the environment of the well  401 , which may include a mixture of oil, water, gas, and fluids used in oil and gas extraction. The weight of the motors  301  in a series of connected seismic tools  101  may contribute to fatigue in the logging cable  15 , and make movement and handling of the seismic tools  101  more difficult. The motor  301  may also increase the amount of power needed to operate multiple seismic tools  301 . 
     Thus, there is a need for an apparatus and method for anchoring a seismic tool within a well without using a motor. 
     SUMMARY 
     In various embodiments, an apparatus and method is provided for a motorless seismic tool. 
     In one embodiment, there is an apparatus for a motorless seismic tool that includes a body; a motorless clamping mechanism connected to the body; and an anchoring arm attached to the body and the motorless clamping mechanism. The motorless clamping mechanism is configured to close or open the anchoring arm based on gravity. 
     According to another embodiment, there is an apparatus for a conducting a seismic survey including a telemetry unit; an end unit and at least one motorless seismic tool disposed between the telemetry unit and the end unit. 
     According to still another embodiment, there is a method for deploying motorless seismic tools in a well. The method includes lowering the motorless seismic tools to a desired position within a well; stopping the lowering when the motorless seismic tools reach the desired position within the well; causing an end unit to anchor within the well; lowering the motorless seismic tools further into the well to cause the lowest motorless seismic tool that is not anchored to anchor until all of the motorless seismic tools are anchored within the well; and stopping the lowering of the motorless seismic tools further into the well. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings: 
         FIG. 1  depicts an exemplary seismic tool; 
         FIG. 2  depicts an exemplary diagram of a seismic tool; 
         FIG. 3  depicts an exemplary diagram of an internal view of a seismic tool with a motor; 
         FIGS. 4 a  and 4 b    depict an exemplary seismic tool in use within a well; 
         FIG. 5  depicts an exemplary motorless seismic tool; 
         FIG. 6  depicts an exemplary exploded view of a motorless seismic tool; 
         FIGS. 7 a , 7 b , and 7 c    depict exemplary diagram views of a motorless seismic tool with an anchoring arm in a closed position; 
         FIGS. 8 a , 8 b , and 8 c    depict exemplary diagram views of a motorless seismic tool with an anchoring arm in an open position; 
         FIGS. 9 a  and 9 b    depict exemplary diagram views of a motorless seismic tool including a secondary housing with an anchoring arm in a closed position; 
         FIGS. 10 a  and 10 b    depict exemplary diagram views of a motorless seismic tool including a secondary housing with an anchoring arm in an open position; 
         FIG. 11  depicts exemplary motorless seismic tools deployed within a well before being anchored; 
         FIG. 12  depicts exemplary motorless seismic tools deployed within a well where a motorless seismic tool is anchored; 
         FIG. 13  depicts exemplary motorless seismic tools deployed within a well where the all motorless seismic tools are anchored; 
         FIG. 14  depicts exemplary motorless seismic tools and seismic tools with motors deployed and anchored within a well; 
         FIG. 15  depicts an exemplary procedure for anchoring motorless seismic tools; and 
         FIG. 16  depicts an exemplary procedure for unanchoring motorless seismic tools. 
     
    
    
     DETAILED DESCRIPTION 
     The following description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. In various embodiments as illustrated in  FIGS. 1-16 , an apparatus and method for a motorless seismic tool is provided. 
     Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. 
       FIG. 5  depicts an exemplary motorless seismic tool. The motorless seismic tool  501  may include a main housing  102 , an upper cable head  103 , a lower cable head  104 , and an anchoring arm  106 , similar to the seismic tool  101 . The upper cable head  103  may be separable from the main housing  102 . The anchoring arm  106  of the motorless seismic tool  501  may be attached to the upper cable head  103 , and a control arm  502  may be attached to the main housing  102  and the anchoring arm  106 . The motorless seismic tool  501  may also include at least one sensor  503 . The sensor  503  may be contained within the main housing  102 , and may be a hydrophone, geophone, accelerometer, temperature sensor, density sensor, gravitometer, or any other suitable type of sensor or combination of sensors. 
     The control arm  502  may be attached to both the main housing  102  and the anchoring arm  106  in any suitable manner to allow the control arm to rotate at both ends. Any motion of the joint between the control arm  502  and the main housing  102  towards or away from the joint between the anchoring arm  106  and the upper cable head  103  may be translated into motion of the anchoring arm  106  at the joint between the anchoring arm  106  and the control arm  502 . 
       FIG. 6  depicts an exemplary exploded view of a motorless seismic tool. The motorless seismic tool  501  may include an anchoring spring  601 , a piston  602 , and a chamber  603 . Note that piston  602  does not seal chamber  603  and does not have to have an exterior diameter that matches an interior diameter of chamber  603 . In other words, the exterior diameter of piston  602  may be substantially less than the interior diameter of chamber  603 . The motorless seismic tool  501  may also include a secondary housing  604 . The chamber  603  may be attached to the upper cable head  103  in any suitable manner, such as, for example, bolts, screws, or welding. The piston  602  may be attached to the main housing  102 , for example, by being welded or bolted to a suitable support structure within the main housing  102 , or may be formed as part of the main housing  102 . In one application, the piston  602  may be attached to the upper cable head  103  and the chamber  603  may be attached to the main housing  102 . The piston  602  may be inserted into the chamber  603 , with the shaft of the piston  602  going through an appropriately sized opening in the base of the chamber  603  such that, for example, the head of the piston  602  may be able to travel between resting at the bottom of the chamber  603  and being even with the top of the chamber  603  as the shaft travels through the opening. The piston  602  and the chamber  603  may act as a mechanical stop for both the expansion and contraction of the motorless seismic tool  501 , with the piston  602  being stopped when the head of the piston  602  contacts the bottom of the chamber  603  or the top of the chamber  603 . The piston  602  and the chamber  603  may be made from any suitable material, and may be in any suitable shape for use within the main housing  102  of the motorless seismic tool  501 . For example, as depicted in  FIG. 6 , the piston  602  and the chamber  603  may be cylindrical. Other suitable mechanisms may be used in place of the piston  602  and the chamber  603  as a mechanical stop, such as, for example, a rope. 
     The anchoring spring  601  may be wrapped around the outside of the chamber  603 . The anchoring spring  601  may be any suitable spring or coil, such as an extension spring, with any suitable number of windings and made of any suitable material, may have any suitable spring force, and may be of suitable strength during contraction to cause the piston  602  to rise within the chamber  603  and draw the main housing  102  and the upper cable head  103  towards each other. One or more of the upper coils, or the top end, of the anchoring spring  601  may be attached to the top of the chamber  603  or the upper cable head  103 , and one or more of the lower coils, or the bottom end, of the anchoring spring  601  may be attached to the main housing  102 . The piston  602  and the chamber  603  may serve to limit the degree to which the anchoring spring  601  can extend and contract. Alternatively, more than one spring or coil in any suitable arrangement may be used as the anchoring spring  601 . The anchoring spring  601  may have a stiffness such that level of strain that occurs in the anchoring spring  601  when the anchoring spring  601  is subject only to the weight of the logging cable  105  may not cause the anchoring spring  601  to contract enough to release the anchoring arm  106 , unanchoring the motorless seismic tool  501 . 
     The secondary housing  604  may be, for example, a housing of similar material and shape to the main housing  102 , and may be of suitable size to be contained within the main housing  102 . The secondary housing  604  may be attached to the upper cable head  103  in any suitable manner, and may enclose the anchoring spring  601 , the piston  602 , and the chamber  603 . When the anchoring spring  601  is contracted, for example, in a resting state, the secondary housing  604  may be contained within the main housing  102 . When the anchoring spring  601  is extended, the secondary housing  604  may be exposed, and may serve to protect the anchoring spring  601  from the environment outside of the motorless seismic tool  501 . 
     The mechanical stop used by the motorless seismic tool  501  may also include a dampener. The dampener may be any suitable mechanism or adjustment to the mechanical stop that may prevent unwanted deployment of the anchoring arm  106  by the anchoring spring  601 . The dampener may be, for example, oil added into the chamber  603 , that may slow the movement of the piston  602  within the chamber  603 . The dampener may also be, for example, a trigger. The trigger may hold the anchoring arm  106  in place until the trigger is activated, for example, by the motion of the piston  602  within the chamber  603 . 
       FIGS. 7 a , 7 b , and 7 c    depict exemplary diagram views of a motorless seismic tool with an anchoring arm in a closed position.  FIG. 7 a    depicts an exemplary cross-sectional view of the coils of the anchoring spring  601 , the piston  602 , and the chamber  603 , when the anchoring spring  601  is extended.  FIG. 7 b    depicts an exemplary view of the extended anchoring spring  601  wrapped around a cross-sectional view of the piston  602  and the chamber  603 .  FIG. 7 c    depicts an exemplary view of the extended anchoring spring  601  wrapped around the piston  602  and the chamber  603 . Arm  502  may be attached to anchoring arm  106 , for example, with a bolt. When the seismic tool  501  is subjected to forces that pull the lower cable head  104  away from the upper cable head  103 , the anchoring spring  601  may extend and the head of the piston  602  may move towards the bottom of the chamber  603 . The anchoring arm  106  and the control arm  502  may be arranged so that when the head of the piston  602  is at the bottom of the chamber  603 , the control arm  502  may hold the anchoring arm  106  in a closed position against the main housing  102 . 
       FIGS. 8 a , 8 b , and 8 c    depict exemplary diagram views of a motorless seismic tool with an anchoring arm in an open position.  FIG. 8 a    depicts an exemplary cross-sectional view of the coils of the anchoring spring  601 , the piston  602 , and the chamber  603  when the anchoring spring  601  is contracted.  FIG. 8 b    depicts an exemplary view of the contracted anchoring spring  601  wrapped around a cross-sectional view of the piston  602  and the chamber  603 .  FIG. 8 c    depicts an exemplary view of the extended anchoring spring  601  wrapped around the piston  602  and the chamber  603 . When the seismic tool  501  is not subjected to forces that pull the lower cable head  104  away from the upper cable head  103 , the anchoring spring  601  may be contracted, for example, in a resting state, and the head of the piston  602  may be at the top of the chamber  603 . The anchoring arm  106  and the control arm  502  may be arranged so that when the piston  603  is at the bottom of the chamber  603 , the control arm  502  may hold the anchoring arm  106  in an open position away from the main housing  102 . 
       FIGS. 9 a  and 9 b    depict exemplary diagram views of a motorless seismic tool including a secondary housing with an anchoring arm in a closed position.  FIG. 9 a    depicts an exemplary view of the secondary housing  604  when the anchoring spring  601  is extended.  FIG. 9 b    depicts an exemplary cut-away view of the secondary housing  604  when the anchoring spring  601  is extended. When the anchoring spring  601  is extended and the anchoring arm  106  is closed, the secondary housing  604  may be extended from the main housing  102 , and may protect the anchoring spring  601 , part of the piston  602  within the chamber  603 , and the chamber  603 . 
       FIGS. 10 a  and 10 b    depict exemplary diagram views of a motorless seismic tool including a secondary housing with an anchoring arm in an open position.  FIG. 10 a    depicts an exemplary view of the main housing  102  when the anchoring spring  601  is contracted.  FIG. 10 b    depicts an exemplary cut-away view of the main housing  102  and the secondary housing  604  when the anchoring spring  601  is contracted. When the anchoring spring  601  is contracted and the anchoring arm  106  is open, the secondary housing  604  may be retracted within the main housing  102 . The anchoring spring  601 , the piston  602 , and the chamber  603  may be contained within both the main housing  102  and the secondary housing  604 . 
     When the anchoring spring  601  transitions between an extended state, as depicted in  FIGS. 7 a , 7 b , and 7 c   , and a contracted state as depicted in  FIGS. 8 a , 8 b , and 8 c   , the anchoring arm  106  may move as well. The anchoring arm  106  may move towards an open position while the anchoring spring  601  contracts, and towards a closed position when the anchoring spring  601  extends. 
       FIG. 11  depicts exemplary motorless seismic tools deployed within a well before being anchored. To conduct a seismic survey of the earth surrounding the well  401 , a number, such as, for example, 20 to 25, of the seismic tools  501  may be lowered into the well  401 , along with other seismic survey equipment. For example, as depicted in  FIG. 11 , the motorless seismic tools  1106 ,  1107 ,  1108 , and  1109  may be exemplary motorless seismic tools  501 . The motorless seismic tools  1106 ,  1107 ,  1108 , and  1109  may be lowered into the well  401  from the surface by the logging cable  1104 . The logging cable  105  may connect the motorless seismic tools  1106 ,  1107 ,  1108 , and  1109  to each other, a telemetry unit  1105  and an end unit  1110 . The logging cable  1104  may connect an electronic device  1102  on the surface to the telemetry unit  1105 , and may be used to control the descent and ascent of all of the seismic survey equipment within the well  401 . In one application, the logging cable  1104  may be different from logging cable  105 . The electronic device  1102  may serve as an interface between the motorless seismic tools  1106 ,  1107 ,  1108 , and  1109  and a computer  1101  through a link  1103 . The computer  1101  may be any suitable computing device for gathering data from and sending commands to the motorless seismic tools  1106 ,  1107 ,  1108 , and  1109 , and the end unit  1110 . The telemetry unit  1105  may collect data from sensors in the motorless seismic tools  1106 ,  1107 ,  1108 , and  1109 , and the end unit  1110  for transmission to the electronic device  1102  and the computer  1101 . The end unit  1110  may be structured similarly to the seismic tool  101 , and may be a motor unit including the motor  301  to operate the anchoring arm  106 , and may also include additional mass which may facilitate the lowering of the end unit  1110  and attached seismic survey equipment into the well  401 . The end unit  1110  may include the same sensors as the motorless seismic tools  501 . In one application, there is a end unit  1110  for any N motorless seismic tools  501 , where N is a number between 2 and 20. In one application, N is 10. The end unit  1110  may use any suitable form of activation for the anchoring arm  106 . The end unit  110  may also be a weight with no anchoring arm  106 . 
     While the motorless seismic tools  1106 ,  1107 ,  1108 , and  1109  are being lowered into the well  401  by the logging cable  1104 , the end unit  1110  may be supported by the logging cable  105  between the end unit  1110  and the motorless seismic tool  1109 . This may create tension in the logging cable  105  between the end unit  1110  and the motorless seismic tool  1109 . The tension in the logging cable  105  may pull down on the lower cable head  104  and the main housing  102  of the motorless seismic tool  1110  causing its anchoring spring  601  to extend and its anchoring arm  106  to be in the closed position, for example, as depicted in  FIGS. 7 a , 7 b , and 7 c   . This effect may be repeated with the other motorless seismic tools  1106 ,  1107 , and  1108 , as tension in the logging cable  105  from the weight of lower equipment causes expansion of the anchoring springs  601 . 
       FIG. 12  depicts exemplary motorless seismic tools deployed within a well where a motorless seismic tool is anchored. After the motorless seismic tools  501  deployed within the well  401  have reached their desired positions, the motorless seismic tools  501  may be anchored. For example, as depicted in  FIG. 12 , the anchoring arm  106  of the end unit  1110  may be opened. The end unit  1110  may use the motor  301 , or any other suitable mechanism (e.g., bow springs, electromagnetic systems, explosives, etc.), to open the anchoring arm  106  after receiving a command from the computer  1101 . The end unit  1110  may also rest on the bottom of the well  401  instead of deploying the anchoring arm  106 . In another embodiment, the end unit  1110 , which would rest on the bottom of the well, would be a simple weight and not be an electronic module. In other words, end unit  1110  may have no components, contrary to seismic tool  501  illustrated in  FIG. 5 , just a simple weight that maintains the anchoring arm of the unit above closed. Then, as explained further in this paragraph, the next seismic tool is lowered until its anchoring arm opens and the seismic tool is anchored to the well. Once the end unit  1110  is anchored within the well  401 , or resting on the bottom of the well  401 , the motorless seismic tools  1106 ,  1107 ,  1108 , and  1109  may be slightly lowered in the well  401  so that the tension in the logging cable  105  between the end unit  1110  and the motorless seismic tool  1109  and the weight pulling down on the anchoring spring  601  may both decrease. The logging cable  105  between the end unit  1110  and the motorless seismic tool  1109  may slacken. The decrease in weight pulling down on the anchoring spring  601  may allow the anchoring spring  601  to contract, pulling up the slack in the logging cable  105 . The contraction of the anchoring spring  601  may cause the piston  602  to move up in the chamber  603  and may draw the main housing  102  of the motorless seismic tool  1109  upwards towards the upper cable head  103 . The joint between the control arm  502  and the main housing  102  may move upwards along with the main housing  102 , which may in turn cause the anchoring arm  106  to open. Once the anchoring arm  106  has contacted the wall  402 , the anchoring arm  106  may push against the wall  402  as the anchoring arm  106  continues opening, causing the main housing  102  to be pushed up against the wall  402  opposite the anchoring arm  106 . After the main housing  102  is pushed against the wall  402  and held in place by the anchoring arm  106 , the anchoring arm  106  may be physically prevented from opening any further. This may arrest the upwards motion of the main housing  102 , preventing further contraction of the anchoring spring  601 . The motorless seismic tool  1109  may be anchored. Next, the other motorless seismic tools  1106 ,  1107 , and  1108  may be further lowered into the well  401  to engage the anchoring arm  106  of the next motorless seismic tool  1108 . This process may continue until the anchoring arms  106  of all the motorless seismic tools  1106 ,  1107 ,  1108  and  1109  are in the opened position. As noted above, an end unit  1110  may be present between a given number of the motorless seismic tools  501  to facilitate this process. 
       FIG. 13  depicts exemplary motorless seismic tools deployed within a well where all the motorless seismic tools are anchored. After the motorless seismic tool  1109  is anchored within the well  401 , the other motorless seismic tools  1106 ,  1107 , and  1108 , may anchor in a similar manner. The anchoring of the motorless seismic tool  1109  may remove weight pulling down on the motorless seismic tool  1108  through tension in the logging cable  105 , similar to the manner in which the anchoring of the end unit  1110  removed weight pulling down on the motorless seismic tool  1109 , as described in  FIG. 12 . This may allow the anchoring spring  601  of the motorless seismic tool  1108  to contract, opening the anchoring arm  106  of the motorless seismic tool  1108  and anchoring the motorless seismic tool  1108  within the well  401 . The anchoring of the motorless seismic tool  1108  may remove the weight pulling down on the motorless seismic tool  1107 , which may then anchor in the same manner as the motorless seismic tools  1108  and  1109 . The anchoring of the motorless seismic tool  1107  may in turn remove the weight pulling down on the motorless seismic tool  1106 , which may also anchor. As depicted in  FIG. 13 , all of the motorless seismic tools  1106 ,  1107 ,  1108  and  1109  may anchor within the well  401  once the end unit  1110  has used the motor  301  to anchor. 
     The motorless seismic tools  1106 ,  1107 ,  1108 , and  1109  anchored within the well  401  may be un-anchored as now discussed. When the time comes to un-anchor the motorless seismic tools  1106 ,  1107 ,  1108 , and  1109 , the operator may pull up the top most motorless seismic tool  1107  through the logging cable  1104 , the telemetry unit  1105 , and the logging cable  105 . When this occurs, the anchoring spring  601  of the motorless seismic tool  1107  may start to extend and slowly brings anchoring arm  106  to a closed position, thus releasing the motorless seismic tool  1107 . By continuing to pull up on the next motorless seismic tool  1108 , its anchoring spring  601  may start to extend, which results in the anchoring arm  106  changing from an opened position to a closed position. The un-anchoring procedure may then repeat with the motorless seismic tools  1106  and  1107 . When the last anchored unit is the end unit  1110 , the operator may send an instruction from the computer  1101  to close the anchoring arm  106  by using its motor  301 , or other suitable mechanism. If the end unit  1110  is not anchored, but is resting on the bottom of the well  401 , the end unit  1110  may be pulled up. 
     As depicted in  FIGS. 11, 12 and 13 , all of the seismic tools connected between the telemetry unit  1105  and the end unit  1110  may be motorless seismic tools  501 . Alternatively, a mixture of motorless seismic tools  501  and seismic tools  101  with motors  301  may be used.  FIG. 14  depicts exemplary motorless seismic tools and seismic tools with motors deployed and anchored within a well. In this embodiment, unit  1110  may be a weight unit having no sensors. When mixing units of the motorless seismic tool  501  and the seismic tool  101 , any suitable ratio and arrangement may be used. For example, as depicted in  FIG. 14 , the exemplary motorless seismic tools  1107 ,  1108 , and  1109  may alternate with seismic tools  1401  and  1402 , which may be exemplary seismic tools  101  and may include motors  301 . The seismic tools  1401  and  1402  may control the anchoring of the motorless seismic tools  1107  and  1108 , respectively, similar to the manner in which end unit  1110  may control the anchoring of the motorless seismic tool  1109 , as described previously. Commands from the computer  1101  may, for example, cause the seismic tool  1401  to anchor using the motor  301  and the anchoring arm  106 . Once the seismic tool  1401  is anchored, the motorless seismic tool  1107  may also anchor as described previously, regardless of whether any of the lower motorless seismic tool  1108  and  1109 , the seismic tool  1402 , or the end unit  1110 , has anchored. 
       FIG. 15  depicts an exemplary procedure for anchoring motorless seismic tools. In block  1501 , motorless seismic tools may be lowered to a desired position within a well. For example, as depicted in  FIG. 11 , several motorless seismic tools  501 , along with other seismic survey equipment, may be lowered from the surface into the well  401  with the logging cable  1104 . The motorless seismic tools  501  may be lowered until they are in a desired position within the well  401 . 
     In block  1502 , the lowering of the motorless seismic tools may be stopped. For example, once the motorless seismic tools  501  have reached the desired position within the well  401 , the letting out of the logging cable  1104  on the surface may be stopped, causing the motorless seismic tools  501  to stop being lowered into the well  401 . 
     In block  1503 , an end unit may be anchored. For example, as depicted in  FIG. 12 , the end unit  1110  may receive a command from the computer  1101  to anchor. The end unit  1110  may use the motor  301 , or other suitable mechanism, to cause the anchoring arm  106  to contact the wall  402  and push the end unit  1110  against the opposite part of the wall  402 , anchoring the end unit  1110 . The end unit  1110  may also be resting on the bottom of the well  401 , in which case the anchoring arm  106  may not be needed to anchor the end unit  1110 . 
     In block  1504 , the motorless seismic tools may be lowered to anchor the lowest unanchored motorless seismic tool. For example, the unanchored motorless seismic tool  501  immediately above either an end unit  1110  or other motorless seismic tool  501  that has just anchored may be the lowest unanchored motorless seismic tool  501 . By lowering the motorless seismic tools  501 , for example, using the logging cable  1104 , slack may develop in the logging cable  105  between the just anchored seismic survey equipment and the lowest unanchored motorless seismic tool  501 . Slack in the logging cable  105  may allow the anchoring spring  601  of lowest unanchored motorless seismic tool  501  to contract, causing the control arm  502  to move the anchoring arm  106  into an open position. This may result in lowest unanchored motorless seismic tool  501  becoming anchored within the well  401 . 
     In block  1505 , it may be determined whether there are any unanchored motorless seismic tools left in the well. The determination may be made in any suitable manner, such as, for example, through data received at the computer  1101  from the motorless seismic tools  501 . If all of the motorless seismic tools  501  within the well  401  have anchored, for example, as in  FIG. 13 , flow may proceed to block  1506 . Otherwise, flow proceeds back to block  1504 , where the new lowest unanchored motorless seismic tool  501  may anchor. 
     In block  1506 , the letting out of the logging cable may be stopped. Once all of the motorless seismic tools  501  have anchored, for example, as depicted in  FIG. 13 , the logging cable  1104  may no longer be let out, as the motorless seismic units  501  are anchored and letting out the logging cable  1104  will no longer lower them. 
       FIG. 16  depicts an exemplary procedure for unanchoring motorless seismic tools. In block  1601 , the motorless seismic tools may be pulled up to unanchor the highest anchored motorless seismic tool. For example, the logging cable  1104  may be used to pull up on the anchored motorless seismic tools  501 . The force of the logging cable  1104  pulling upwards may pull up the logging cable  105  connected to the highest unanchored motorless seismic tool  501 . This may cause the upper cable head  103  of the highest unanchored motorless seismic tool  501  to move upwards, the anchoring spring  601  to extend, and the control arm  502  to move the anchoring arm  106  to a closed position, unanchoring the motorless seismic tool  501 . 
     In block  1602 , it may be determined whether there are any anchored motorless seismic tools left in the well. The determination may be made in any suitable manner, such as, for example, through data received at the computer  1101  from the motorless seismic tools  501 . If all of the motorless seismic tools  501  within the well  401  have unanchored, for example, as in  FIG. 11 , flow may proceed to block  1603 . Otherwise, flow proceeds back to block  1601 , where the new highest anchored motorless seismic tool  501  may unanchor. 
     In block  1603 , an end unit may be unanchored. For example, after all of the motorless seismic tools  501  have been unanchored, the end unit  1110  may be unanchored. The end unit  1110  may receive a command from the computer  1101  to unanchor. The end unit  1110  may use the motor  301 , or other suitable mechanism, to cause the anchoring arm  106  to close, unanchoring the end unit  1110 . The end unit  1110  and the motorless seismic tools  501  may then be retrieved from or moved into a different position within the well  401 . 
     The motorless seismic tools  501  may be unanchored from the well  401  in any other suitable manner. For example, a tractor at the deepest end of the well may be used to pull down on the lowest motorless seismic tool  501  within the well  401 , causing the motorless seismic tool  501  to unanchor from the well  401 , and resulting in the unanchoring of the rest of the motorless seismic tools  501 . 
     The disclosed exemplary embodiments provide an apparatus and method for a motorless seismic tool. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details. 
     Although the features and elements of the present exemplary embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein. 
     This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims.