Abstract:
A method and apparatus for testing a blowout preventer which includes a plurality of safety devices and an assembly of fluid control valves that are remotely actuatible to an open and closed position for controlling flow of drilling fluids into the well includes a hydraulic power unit control station for remotely and selectively actuating one or more safety devices and fluid control valves to a test orientation. A hydrostatic test system supplies fluid under first and second test pressure and documents any pressure loss due to fluid leaks within the closed system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to provisional application Ser. No. 62/143,995, filed Apr. 7, 2015, the entire contents of which is incorporated herein by reference thereto. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to an automatic testing system for testing the functionality and integrity of various components of a blowout preventer (BOP). A blowout preventer typically includes a number of safety devices for preventing high pressure within a formation from creating a blowout situation. Also a plurality of control valves to direct the flow of pressurized drilling fluid in a safe and controlled manner are associated with the BOP. It is necessary to periodically pressure test these components. 
         [0004]    2. Description of Related Art 
         [0005]    Oil and Gas Exploration risk management includes the ability to control subsurface pressures which may be encountered during drilling operation. The primary mechanism utilized by operators to control downhole pressure is the hydrostatic pressure as a result of the drilling fluid contained within the wellbore. The drilling fluid is engineered and formulated to a density that provides a hydrostatic pressure inside of the wellbore that is greater than the formation pressure being drilled. In the majority of drilling operations, the hydrostatic control of wellbore pressure is adequate. However, from time-to-time the operator may encounter a higher than expected formation pressure where there is not adequate hydrostatic pressure to control the wellbore pressure. During these times the operator relies on a series of mechanical controls to stabilize the wellbore and prevent a “Blow Out”. A blow out is the uncontrolled release of fluid or gas from the wellbore. This event is extremely dangerous and therefore must be avoided if at all possible. The primary mechanical control device utilized by operators to control wellbore pressure is the Blowout Preventer (BOP) assembly. The BOP assembly typically consists of multiple sealing and shearing devices that are hydraulically actuated to provide various means of sealing around the drill string or shearing it off entirely, thereby completely sealing the wellbore. Additionally there is a series of valves attached directly to or remotely located in close proximity to the BOP assembly that make up the pressure control manifold assembly and are inclusive to the BOP assembly. These valves are opened or closed as required to direct pressurized drilling fluid in a safe and controlled manner. Opening or closing these valves to direct the flow of pressurized drilling fluid is commonly referred to within the industry as “aligning the valves”. Valve alignment is principally a manual operation. It is essential that the BOP assembly operate as designed during critical operations. Therefore it is a regulatory requirement to test the functionality and the integrity of the BOP assembly before starting drilling operations and at specific events during the drilling operations. Typically the interval between these tests is approximately 14 days. The BOP Assembly test is a series of pressure tests at a minimum of two pressure levels, low pressure and high pressure. Each test of the series of tests is carried out according to a “Test Plan”. The test plan specifies, among other test requirements, the precise alignment of the valves applicable to the test. A typical test plan can include as many as 30 or more valves which may be required to be aligned differently for each pressure test.  FIG. 1  depicts a typical BOP assembly with the internal multiple sealing and shearing devices such as Annular  34 , Pipe Rams  35 , and Blind Rams  36 , as well as the external valves numbered 1 through 32. The alignment of the valves is a time consuming and problematic manual operation. Proper valve alignment is fully reliant on the diligence of the rig personnel and there is no visual indication that the valves are properly aligned. Conversely the multiple sealing and shearing devices within the BOP are fully automated and remotely operated via an automated hydraulic control system. During a typical BOP assembly pressure test, rig personnel would quickly and accurately align the multiple sealing and shearing devices within the BOP assembly, utilizing the automated controls, as specified by the test plan, but would be required to manually align the BOP Assembly valves outside of the BOP. The pressure test would commence once the multiple sealing and shearing devices and valves of the BOP assembly are deemed and confirmed to be aligned properly as specified by the test plan. During the pressure test, intensifying fluid from a high pressure intensifying pump unit is introduced into the BOP assembly in a volume sufficient to cause the internal pressure within the BOP assembly to rise to the specified level indicated on the test plan. The high pressure intensifying pump is normally a truck or trailer mounted unit which is transported to the rig location when pressure testing is required. These are referred to within the industry as “hydrostatic test units”. The portable hydrostatic test units will remain on location until the test plan is completed, usually about 12 hours. Portable hydrostatic test units are typically a manually operated device where the technician engages or disengages the pump to achieve the test pressure specified by the test plan. Coordination between the drilling rig personnel who are controlling the BOP assembly test and the truck technician is typically handled via a two-way radio. When the rig personnel are reasonably sure the BOP assembly valves are align correctly and they deem it safe to conduct a test, they will radio the truck to commence the test. Subsequent to a successful pressure test the BOP assembly will be aligned for the next test. This procedure would be repeated multiple times until the entire test plan was completed. A schematic of a rig setup typical of current technology as described above is depicted in  FIG. 2 . BOP assembly internal sealing and shearing devices  34 ,  35 ,  36 , of BOP  40  and hydraulic power unit  50  are in control fluid communication via control fluid conduit  45 . Control fluid conduit  45  is made up of multiple discrete fluid control circuits. BOP assembly external valves  41  are in intensifying fluid communication with BOP assembly  40 . Hydraulic power unit  50  includes a local control station  60 . Hydraulic power unit  50  is in signal communication with remote control station  70  via signal cable  80 . BOP assembly external valves  41  are manually operated as required. Additionally during the test period portable hydrostatic test system  90  is temporally placed in intensifying fluid communication with BOP assembly internal sealing and shearing devices  34 - 36  via intensifying fluid conduit  100 . During a typical pressure test of the BOP assembly, BOP assembly internal sealing and shearing devices  34 ,  35 , and  36  are aligned according to the test plan by providing the proper control signals from remote control station  70  via signal cable  80 . BOP assembly external valves  1 - 32  are manually aligned as required by the test plan. The rig personnel confirm that the valves are properly aligned and that it is safe to proceed with the pressure test. The rig personal will signal the technician of portable hydrostatic test system  90  via a two-way radio to commence the pressure test. The technician of portable hydrostatic test system  90  will manually initiate the high pressure intensifying pump of portable hydrostatic test system  90 . High pressure intensifying fluid from portable hydrostatic test system  90  will intensify the internal pressure of BOP assembly internal sealing and shearing devices  42  and BOP assembly external valves  41  according to the specific alignment schedule of the test plan via intensifying fluid conduit  100 . Subsequent to a successful pressure test, intensifying fluid is relived from BOP assembly internal sealing and shearing, devices  35 .  36  and BOP assembly external valves  41  via portable hydrostatic test system  90  and intensifying fluid conduit  100 . At this point BOP assembly internal sealing and shearing devices  34 .  35 .  36  and BOP assembly external valves  1 - 32  will be aligned according to the test plan and the next subsequent test can be initiated. This process is repeated for each test of the test plan. At the completion of the test plan portable hydrostatic test system  90  and intensifying fluid conduit  100  will be disconnect from the BOP assembly in preparation for transportation to the rig sight. In approximately 14 days the entire process will be repeated. 
         [0006]    The entire pressure cycle of these tests are performed without the use of automation. Automating this process would help to insure continuity and safety of the pressure procedure between the hydrostatic unit and the BOP assembly. The manual and separate nature of the test procedure is problematic and dangerous. Additionally the manual process of aligning the valves is very time consuming. It is not uncommon for this part of the test to consume more time than the actual pressure test. It would be much more desirable to have an improved system that fully automates the alignment of the valves. Hydraulically operated valves are commercially available, for example the Valves Works USA FC series valve, and are suitable for use as a component of a fully automated BOP Assembly operating and testing system. These valves respond to intensified hydraulic fluid to open or close as directed by control valves and a hydraulic power source. Alternatively other types of valves could be used which are electrically or air operated. Thus there remains a need for a fully automated system to provided BOP Assembly operating and testing capabilities integral to one system capable of being operated from a single remote control panel, a single local control panel, or as part of an automated drilling control system. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    The present invention is directed to a system and method for pressure testing a BOP assembly that includes a plurality of hydraulically actuated safety devices and a plurality of valves for regulating drilling fluid pressure within the well. 
         [0008]    The invention includes the provision of remotely actuatable valves than can be positioned for testing purposes automatically and remotely by the same hydraulic power source used to actuate the safety devices in the event of an emergency. Alternately the valves may be remotely actuated by an electrical power source selectively connected to electrical actuators such as solenoids provided on the valves. 
         [0009]    The following detailed description and drawings of the preferred embodiment of the Automated BOP Control and Test System is intended as an exemplification of the principals of the invention and not intended to limit the invention to any specific embodiment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic view of a conventional blowout preventer showing various safety control devices and pressure controlling valves. 
           [0011]      FIG. 2  is a schematic showing of a conventional testing arrangement for a blowout preventer. 
           [0012]      FIG. 3  is a schematic showing of an automated control and testing system for a blowout preventer according to an embodiment of the invention 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0013]    As shown in  FIG. 1 , a typical blowout preventer assembly  40  includes a plurality of valves  1 - 32  for controlling the pressurized drilling fluid in a safe and controlled manner. 
         [0014]    BOP assembly  40  also includes a number of sealing and shearing devices  34 ,  35  and  36  that are hydraulically actuated to provide various means of sealing around the drill string or shearing it off completely. 
         [0015]    In this example, the BOP includes an annular sealing device  34 , pipe rams  35  and blind rams  36 . 
         [0016]    A typically testing arrangement is shown in  FIG. 2 . The blowout preventer assembly  40  is connected to a hydraulic power unit  50  utilized to actuate the safety devices  34 ,  35 , and  36  in the event of an emergency. Hydraulic power unit  50  may be controlled by a local control station  60  or a remote control station  70  via a control cable  80  or a wireless control. 
         [0017]    The safety devices and external valves are connected to a portable hydraulic test system  90  which generates testing fluid under various pressures for testing the integrity of the various valves and safety devices as described above. 
         [0018]    As an example, the chart below illustrates a typically sequence of tests involving the various valves and safety devices. The valves are aligned and set by hand. 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
               
               
                 Test 
                   
                 Low Test 
                 High Test 
               
               
                 Number 
                 Test Against 
                 Pressure &amp; Times 
                 Pressure &amp; Times 
               
               
                   
               
             
             
               
                 Test 1 
                 V1, V2, V8 Pipe Rams, 
                 Low: 250 psi, 5 minutes 
                 High: 5000 psi, 10 minute 
               
               
                   
                 V20, V22, V24, V25 
               
               
                 Test 2 
                 V7, V(, Pipe Rams, 
                 Low: 250 psi, 5 minutes 
                 High: 5000 psi, 10 minute 
               
               
                   
                 V19, V21, V23, V25 
               
               
                 Test 3 
                 Topdrive Hydraulic 
                 Low: 250 psi, 5 minutes 
                 High: 5000 psi, 10 minute 
               
               
                   
                 Valve, Pipe Rams, 
               
               
                   
                 V10, V13 
               
               
                 Test 4 
                 Lower Topdrive 
                 Low: 250 psi, 5 minutes 
                 High: 5000 psi, 10 minute 
               
               
                   
                 Manual Valve, Pipe 
               
               
                   
                 Rams, V11, V12 
               
               
                 Test 5 
                 Lower Topdrive 
                 Low: 250 psi, 5 minutes 
                 High: 3500 psi, 10 minute 
               
               
                   
                 Manual Valve, 
               
               
                   
                 ANNULAR 
               
               
                   
                 PREVENTER, V11, V12 
               
               
                 Test 6 
                 V14, Blind Rams, V19, 
                 Low: 250 psi, 5 minutes 
                 High: 5000 psi, 10 minute 
               
               
                   
                 V21, V23 
               
               
                 Test 7 
                 Casing, V14 Blind 
                 Low: 250 psi, 5 minutes 
                 High: 1500 psi, 30 minute 
               
               
                   
                 Rams, V19, V21, V23, 
               
               
                   
                 V15, V18 
               
               
                 Test 8 
                 Cup Type Tester, V14, 
                 Low: 250 psi, 5 minutes 
                 High: 5000 psi, 10 minute 
               
               
                   
                 Pipe Rams, V19, V21, 
               
               
                   
                 V23, V15, V18 
               
               
                 Test 9 
                 Cup Type Tester, V14, 
                 Low: 250 psi, 5 minutes 
                 High: 5000 psi, 10 minute 
               
               
                   
                 Pipe Rams, V19, V21, 
               
               
                   
                 V23, V16, V17 
               
               
                   
               
             
          
         
       
     
         [0019]    Reffering to  FIG. 3  of an embodiment of the invention will be decribed. 
         [0020]    A schematic of a rig setup utilizing the new and unique features of the current invention is depicted in  FIG. 3 . BOP assembly internal sealing and shearing devices  34 - 36 . BOP  40  assembly external automated valves  1 - 32  shown schematically at  41 , and hydraulic power unit  50  are in control fluid communication via control fluid conduit  45 . Control fluid conduit  45  is made up of multiple discrete fluid control circuits. Hydraulic power unit  50  may include local control station  60 . Hydraulic power unit  50  and hydrostatic test system  90  are also in signal communication with remote control station  70  via signal cable  80 . Hydrostatic test system  90  is in intensifying fluid communication with BOP assembly internal sealing and shearing devices  34 - 36  via intensifying fluid conduit  100 . A suitable hydrostatic test system is disclosed in U.S. patent application Ser. No. 14/932,727 filed Nov. 4, 2015, the entire contents of which is incorporated herein by reference thereto. BOP assembly external automated valves  1 - 32  are in intensifying fluid communication with hydrostatic test system  90  via conduit  101 . During a test utilizing the new and unique features of the current invention, BOP assembly internal sealing and shearing devices  34 - 36  and BOP assembly external automated valves  1 - 32  are aligned according to the test plan by providing the proper control signals from remote control station  70  via signal cable  80 . For Example: test  1  of the test plan depicted in the chart requires closing the pipe rams of BOP Assembly as well as BOP assembly external automated valves numbers  1 ,  2 ,  8 ,  20 ,  22 ,  24 , and  25 . A suitable computer program within remote control station  70  would enable the specific solenoid valve of hydraulic power unit  50 , via signal cable  80 , directing hydraulic control fluid, via control fluid conduit  45  to close the Pipe Rams of BOP assembly  40 . Additionally the suitable computer program within remote control station  70  would enable the specific solenoid valves of hydraulic power unit  50 , via signal cable  80 , directing intensified hydraulic control fluid, via control fluid conduits  45  and  46  to close BOP assembly external automated valves numbers  1 ,  2 ,  8 ,  20 ,  22 ,  24 , and  25 . Subsequent to remote control station  70  confirming proper alignment of BOP assembly internal sealing and shearing devices  34 - 36  and BOP assembly external automated valves  1 - 32  via signal cable  80 , remote control station  70  will initiate the hydrostatic pressure test of BOP assembly internal sealing and shearing devices  34 - 36 , and selected BOP assembly external automated valves  1 - 32  via signal cable  80 . High pressure intensifying fluid from hydrostatic test system  90  will intensify the internal pressure of BOP assembly internal sealing and shearing devices  34 - 36  and BOP assembly external valves  1 - 32  according to the specific alignment schedule of the test plan via intensifying conduits  100  and  101 . 
         [0021]    Subsequent to a successful pressure test, intensifying fluid is relived from BOP assembly internal sealing and shearing devices  34 - 36  and BOP assembly external valves  1 - 32  via hydrostatic test system  90  and intensifying fluid conduits  100  and  101 . BOP assembly internal sealing and shearing devices  34 - 36  and BOP assembly external valves  1 - 32  will be aligned for the next test according to the test plan by providing the proper control signals from remote control station  70  via signal cable  80  to hydraulic power unit  50  and hydrostatic test system  90  so the next subsequent test can be initiated. This process is repeated for each test of the test plan. 
         [0022]    Utilizing the new and unique features of the current invention provides for fully automatic, integrated, BOP assembly operation and testing thereby significantly increasing safety, while dramatically reducing cost. The principles, preferred embodiment, and mode of operation of the present invention have been described in the foregoing specification. This invention is not to be construed as limited to the particular forms disclosed, since these are regarded as illustrative rather than restrictive. Moreover, variations and changes may be made by those skilled in the art without departing from the spirit of the invention. For example an electrical control system could be used for electrically controlling valve  1 - 32  to an open or closed position with the use of solenoid controlled valves. 
         [0023]    Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the invention as defined by the appended claims.