Abstract:
The method of non-intrusively collecting down hole information by providing one or more information collection devices in the annular area outside one or more casing strings and inside the drilled hole the one or more casing strings are suspended within, supporting the one or more casing strings in one or more hangers within a wellhead, providing one or more devices which transmit information outside the one or more casing strings and proximate the one or more hangers, providing one or more wirings between the one or more information collection devices and the one or more devices which transmit information, providing a one or more devices which receive information outside the wellhead to receive information transmitted by the one or more devices which transmit information, and making the wellhead of a non-magnetic material to allow the passage of the transmitted information.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to the method of non-intrusive communication of information regarding down hole annulus information to the surface. 
       CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0002]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0003]    Not applicable 
       REFERENCE TO A “MICROFICHE APPENDIX” 
       [0004]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0005]    The quality of operations in the annulus outside a casing string and within the drilled hole has been purely a matter of speculation as the area is hostile and inaccessible. Of particular interest is the quality of the cement job. The importance of the quality of the cement job was emphasized in the 2010 blowout of the Macondo well in deepwater Gulf of Mexico. 
         [0006]    The best solution to date has been to lower instrumentation into the well bore and attempt to determine the quality of the cement and bonding of the cement to the outside diameter of the casing through the wall of the steel tubing. This is not only a critical path time consuming operation, but must be removed before production can be started. Valuable information regarding the change of well conditions during the lifetime of the well is simply not available. 
         [0007]    The developments of improved measurements made directly in the annuli have been hindered as there has been no reasonable way deliver the information to the surface. As the delivery of information implies an electric signal, the signal must be transmitted up the annulus to the casing support equipment at the surface, past the equipment and out to the environment for access by the personnel. The industry simply has not been able to develop ways of getting electric signals through and past the casing support equipment in remote operations such as are in subsea drilling. 
         [0008]    An indication of the desire to achieve this type information communication has been indicated by the resources which have been expended to gain some of this information in subsea completion systems. The work in this area has involved special tubing hangers with special orientation and electrical stabs in an intrusive manner. This is theoretically possible in subsea drilling systems, but would involve major changes to the design of the equipment. The changes are so major that it simply will not be accomplished. 
         [0009]    The long standing need to access information regarding down hole conditions outside the casing string has been demonstrated by efforts to gather this information from within the well bore through casing walls. However, no satisfactory solutions have been developed prior to this invention which literally allows the instrument to be directly in the environment outside the casing string, and then getting the information back to the operator. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The object of this invention is to provide a method of communication of information from a casing annulus to outside of the support housing without penetrating the housing. 
         [0011]    A second object of this invention is to provide a method of reliably communicating the information up and along the casing annulus. 
         [0012]    A third objective of this invention is to maintain the ability to have well control at all times by making the majority of the length along the outside of the casing of a profile which can be sealed upon by a blowout preventer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a view of a deepwater drilling system which might use the features of this invention 
           [0014]      FIG. 2  is a half section of a wellhead system and BOP Stack connector showing the method of this invention. 
           [0015]      FIG. 3  is a cross section of two strings of casing of  FIG. 2  taken along lines “ 3 - 3 ”. 
           [0016]      FIG. 4  is an expanded portion of  FIG. 3 . 
           [0017]      FIG. 5  is a half section of the wellhead similar to  FIG. 2  showing a remotely operated vehicle (ROV) in a position to access the information regarding the down hole conditions. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Referring now to  FIG. 1 , a view of a complete system for drilling subsea wells  20  is shown in order to illustrate the utility of the present invention. The drilling riser  22  is shown with a central pipe  24 , outside fluid lines  26 , and control lines  28 . 
         [0019]    Below the drilling riser  22  is a flex joint  30 , lower marine riser package  32 , lower blowout preventer stack  34  and wellhead system  36  landed on the seafloor  38 . 
         [0020]    The lower Blowout Preventer stack  34  generally comprises a lower hydraulic connector  37  for connecting to the wellhead system  36 , usually 4 or 5 ram style Blowout Preventers, an annular preventer, and an upper mandrel for connection by the connector on the lower marine riser package  32 . 
         [0021]    Below outside fluid line  26  is a choke and kill (C&amp;K) connector  50  and a pipe  52  which is generally illustrative of a choke or kill line. Pipe  52  goes down to valves  54  and  56  which provide flow to or from the central bore of the blowout preventer stack as may be appropriate from time to time. Typically a kill line will enter the bore of the Blowout Preventers below the lowest ram and has the general function of pumping heavy fluid into the well to overburden the pressure in the bore or to “kill” the pressure. The general implication of this is that the heavier mud will not be circulated, but rather forced into the formations. A choke line will typically enter the well bore above the lowest ram and is generally intended to allow circulation to circulate heavier mud into the well to regain pressure control of the well. 
         [0022]    Normal drilling circulation is the mud pumps  60  taking drilling mud  62  from tank  64 . The drilling mud will be pumped up a standpipe  66  and down the upper end  68  of the drill pipe  47 . It will be pumped down the drill pipe  47 , out the drill bit  45 , and return up the annular area  70  between the outside of the drill pipe  47  and the bore of the hole being drilled, up the bore of the casing  42 , through the subsea wellhead system  36 , the lower blowout preventer stack  34 , the lower marine riser package  32 , up the drilling riser  22 , out a bell nipple  72  and back into the mud tank  64 . 
         [0023]    During situations in which an abnormally high pressure from the formation has entered the well bore, the thin walled central pipe  24  is typically not able to withstand the pressures involved. Rather than making the wall thickness of the relatively large bore central pipe  24  thick enough to withstand the pressure, the flow is diverted to a choke line  26 . It is more economic to have a relatively thick wall in a small pipe to withstand the higher pressures than to have the proportionately thick wall in the larger riser central pipe  24 . 
         [0024]    When higher pressures are to be contained, one of the annular or ram Blowout Preventers are closed around the drill pipe and the flow coming up the annular area around the drill pipe is diverted out through choke valve  54  into the pipe  52 . The flow passes up through C&amp;K connector  50 , up fluid line  26  which is attached to the outer diameter of the riser  24 , through choking means illustrated at  74 , and back into the mud tanks  64 . 
         [0025]    On the opposite side of the drilling riser  24  is shown a cable or hose  28  coming across a sheave  80  from a reel  82  on the vessel  84 . The cable  28  is shown characteristically entering the top of the lower marine riser package  32 . These cables typically carry hydraulic, electrical, multiplex electrical, or fiber optic signals. Typically there are at least two of these systems, which are characteristically painted yellow and blue. As the cables or hoses  28  enter the top of the lower marine riser package  32 , they typically enter the top of the control pod to deliver their supply or signals. When hydraulic supply is delivered, a series of accumulators are located on the lower marine riser package  32  or the lower Blowout Preventer stack  34  to store hydraulic fluid under pressure until needed. 
         [0026]    Below the wellhead  36 , a first casing string  100  is jetted into place and second, third, and fourth casing strings  102 ,  104  and  42  are hung as the well is drilled deeper and cemented in place. It can be seen that a hole was drilled for the second, third, and fourth casing strings, that the strings were landed and cemented in place. The cement is shown at  112 ,  114 , and  116  respectively. 
         [0027]    A hole is being drilled through the fourth casing string by drill string  47  which includes drill bit  45 , heavy weight drill collars  118 , and lighter weight drill pipe  120 . 
         [0028]    Guide base  130  surrounds wellhead system  36  and is shown with a set of docking holes  132  around the perimeter. These hoses will be suitable for the orientation and docking of an ROV (remotely operated vehicle) as a part of one option for recovering down hole information. 
         [0029]    Referring now to  FIG. 2 , hydraulic connector  37  is shown connected to wellhead housing  150  of wellhead system  36 . Hydraulic connector  37  is a hydraulic lock and hydraulic unlock connector which is described in detail in U.S. Pat. No. 6,609,734. Wellhead system  36  comprises wellhead housing  150  having casing hangers  152  and  154  suspended within on shoulder  156 . Seal assemblies  158  and  160  are provided for casing hangers  152  and  154  respectively. Lockdown rings  162  and  164  are provided for casing hangers  152  and  154  respectively. Slots  166  and  168  are representative of one of several slots around casing hangers  152  and  154  respectively which allow circulation past the casing hangers during the cementing process. Casing hangers will characteristically have 8-12 slots around their perimeter. 
         [0030]    Casing strings  170  and  172  are suspended from casing hangers  152  and  154  respectively. Transmitters  180  and  182  are inserted in one of the circulation slots of casing hangers  152  and  154  respectively and are connected to wires  184  and  186  respectively. Wires  184  and  186  are connected to appropriate sensing equipment down in the well. The most likely thing to be sensing in this way will be the quality of the cementing job after landing the respective casing string, however, other applications will include pressure, temperature, and chemical sensing. 
         [0031]    Horizontally positioned from transmitters  182  is receiver  190  which is suspended on bracket  192  which is in turn suspended by cylinder  194  which is suspended from hydraulic connector  37 . Cylinder  194  is shown in the retracted position. In this position, a signal can be transmitted from the transmitter  182  to the receiver  190 , if the wellhead housing  150  is manufactured of a non-magnetic material such as 17-4 HH1150 stainless steel. If the wellhead housing  150  is made of alloy steels of conventional construction, the transmission of information will be blocked as would occur in conventional drill collars. 
         [0032]    When the rod  196  of cylinder  194  is extended the receiver  190  and bracket  192  are moved downwardly as are indicated by  190 A and  192 A. and the receiver will receive information from transmitter  180  rather than transmitter  182 . Alternately, this information from more than one transmitter can be collected by providing multiple receivers to match the multiple transmitters. 
         [0033]    Referring now to  FIG. 3 , casing strings  170  and  172  are shown with wires  184  and  186 . It can be noted that these wires are subjected to both substantial mechanical damage and the need to be sealed upon by blowout prevention equipment in unstable situations which may occur as the casing is being lowered into the well. 
         [0034]    Referring now to  FIG. 4 , and enlarged portion of  FIG. 3  is shown. wires  184  is shown as two wires  200  and  202  having insulation covers  204  and  206  around each respectively. Protective strips  208  and  210  are shown on each side of the wires. These strips are of a greater radial thickness than the wires  200  and  202  plus the insulation  204  and  206 . In this case if physical damage were to be threatened to the soft copper wires, the relatively large cross section steel strips would protect the wires. Encapsulation  212  is provided around the wires and protective strips to give them a smooth profile and to taper off to each end. This encapsulation will allow conventional blowout preventers to seal across the wires in case of an unstable pressure situation within the well bore. 
         [0035]    The wires at  186  are within a similar encapsulation  214 , which can actually be identical to encapsulation  212  in spite of a difference in the diameter of the casing strings. 
         [0036]    Referring now to  FIG. 5 , ROV (remotely operated vehicle)  220  is shown with a belly skid  222  having a docking pin  224  at the front which is engaged with docking holes  132  of guide base  130 . Umbilical or tether  226  can carry the signals back to the surface in the case of a tethered vehicle, or would not exist in the case of an autonomous vehicle. The autonomous vehicle would come to the wellhead system, collect the information, record it, and return to the surface for downloading. 
         [0037]    ROV manipulator arm  228  holds a transmitting and receiving device  230  in its gripper  232 . As the internal transmitters  180  and  182  are of an unknown orientation when landed the ROV will need to land at one or more of the docking holes  132  to locate the signals from the transmitter. Groove  240  and  242  or other identifying marks are put into the wellhead housing  150  to identify the vertical elevation of the transmitters  180  and  182  respectively to assist in this process. Once the orientation is identified, it will be recorded simplifying the acquisition of information in subsequent situations. 
         [0038]    The foregoing description has been to communicate information from the bottom of the well to the surface, however, the same technology can be utilized to send information from the surface down to the bottom of the well. Uses of this can be a variety of tasks from sending instructions to the information collection devices to collect or send information to operating down hole valves. It would even be practical to initiate a down hole operations sequence such as perforating a new pay one in a well. 
         [0039]    A further use of this communication could be to communicate power to charge down hole batteries. 
         [0040]    The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.