High Pressure Wireline Top-Entry Packoff Apparatus and Method

Abstract

A high-pressure packoff apparatus and method are disclosed. The packoff allows wireline entering a top drive drilling head through a top entry access system to be isolated in such a fashion to minimize the leakage and escape of drillstring fluids to the atmosphere. Optionally, an extension housing containing a flow tube assembly can be employed to accomplish the task. The flow tube assembly effectuates a pressure drop along the wireline conduit run therethrough, thus minimizing the likelihood of fluid escaping.

1 . A top drive entry access system including a hydraulic packoff to allow a conduit into a bore of a drillstring, the hydraulic packoff comprising:
 a main body, said main body having a lower connection, a seal bore, an upper connection configured to receive a roller assembly to guide the conduit from the top drive entry access system into a gland assembly, wherein said roller assembly includes a bushing to compress said gland assembly, and a mounting surface;   said lower connection configured to attach to an inlet of the drillstring;   said seal bore configured to receive said gland assembly;   said gland assembly configured to allow the conduit to communicate with the bore of the drillstring without releasing drilling fluids therefrom; and   said mounting surface configured to receive and secure the top drive entry access system thereupon, wherein said mounting surface includes a journal bearing surface configured to allow the rotational movement of the top drive entry access system with respect to said main body.   
   
   
       2 - 9 . (canceled) 
   
   
       10 . The top drive entry access system of  claim 1  wherein said inlet is positioned on a manifold above a top drive drilling head. 
   
   
       11 . The top drive entry access system of  claim 1  wherein an extension housing and a flow tube assembly are positioned between said inlet and said main body. 
   
   
       12 . The top drive entry access system of  claim 11  wherein said extension housing is integral to said main body. 
   
   
       13 . The top drive entry access system of  claim 11  wherein pressures of said drilling fluids are reduced as said fluids extend up said flow tube assembly along the conduit. 
   
   
       14 . The top drive entry access system of  claim 1  further comprising a
 flow tube assembly including a through bore and a plurality of expansion cavities arrayed along a length of said through bore;   said through bore configured to receive the conduit therethrough;   said through bore in fluid communication with said expansion cavities; and   said expansion cavities configured to create a pressure reduction profile about the conduit as it extends along said length of said through bore.   
   
   
       15 . The top drive entry access system of  claim 14  wherein said flow tube assembly includes a fluid port configured to remove fluids and pressure from said through bore. 
   
   
       16 . A hydraulic packoff for a top drive entry drilling assembly, the hydraulic packoff comprising:
 a main body, said main body having a lower connection, a seal bore, and a roller assembly;   said seal bore configured to receive a seal gland assembly configured to allow a conduit to communicate with a bore of a drillstring without releasing drilling fluids therefrom; and   said roller assembly positioned above and configured to guide said conduit into said seal gland assembly, wherein said roller assembly includes a bushing to compress said seal gland assembly.   
   
   
       17 - 20 . (canceled) 
   
   
       21 . The hydraulic packoff of  claim 16  further comprising a mounting surface to attach a top drive entry access system. 
   
   
       22 . The hydraulic packoff of  claim 21  wherein said mounting surface includes a journal bearing configured to allow the rotational movement of said top drive entry access system with respect to said main body. 
   
   
       23 . The hydraulic packoff of  claim 21  wherein said mounting surface includes a thrust bearing configured to resist thrust and bending forces exerted by said top drive entry access system on said main body. 
   
   
       24 . The hydraulic packoff of  claim 16  wherein said lower connection connects to an entry inlet of the top drive drilling assembly. 
   
   
       25 . The hydraulic packoff of  claim 16  further comprising an extension housing extending from said lower connection, said extension housing providing a seal bore to receive a flow tube assembly. 
   
   
       26 . The hydraulic packoff of  claim 16  further comprising:
 a flow tube assembly, said flow tube assembly comprising a through bore and a plurality of expansion cavities arrayed along a length of said through bore;   said through bore configured to receive the conduit therethrough;   said through bore in fluid communication with said expansion cavities; and   said expansion cavities configured to create a pressure reduction profile about the conduit as it extends along said length of said through bore.   
   
   
       27 . The hydraulic packoff of  claim 26  wherein said flow tube assembly includes a fluid port configured to remove fluids and pressure from said through bore. 
   
   
       28 - 32 . (canceled) 
   
   
       33 . A hydraulic packoff for a top entry drilling assembly, the hydraulic packoff comprising:
 a main body, said main body having a lower connection, a seal bore, and a retaining device;   a seal gland configured to be received in said seal bore, said seal gland configured to allow a conduit to communicate with a bore of a drillstring without releasing drilling fluids therefrom;   a flow tube assembly, said flow tube assembly comprising a through bore and a plurality of expansion cavities arrayed along a length of said through bore;   said through bore configured to receive the conduit therethrough;   said through bore in fluid communication with said expansion cavities;   said expansion cavities configured to create a pressure reduction profile about the conduit as it extends along said length of said through bore; and   said retaining device positioned above and configured to compress said gland assembly.   
   
   
       34 . The hydraulic packoff of  claim 33  wherein said retaining device is a roller head. 
   
   
       35 . The hydraulic packoff of  claim 34  wherein said retaining device is a retaining nut. 
   
   
       36 . A method for entering a conduit into a pressurized bore of a drillstring driven by a top drive assembly, the method comprising:
 connecting a hydraulic packoff and an extension housing to an inlet of the drillstring, the inlet located above a drive motor of the top drive assembly;   installing a flow tube assembly inside a bore of the extension housing;   connecting a top entry access system above the hydraulic packoff; and   routing the conduit from a supply, through the top entry access system, into the hydraulic packoff, through the flow tube assembly, through the drillstring inlet and into the drillstring.   
   
   
       37 - 38 . (canceled) 
   
   
       39 . The method of  claim 36  further comprising removing pressurized fluid from a fluid port in communication with a through bore of said hydraulic packoff assembly on the top drive assembly to reduce the pressure in the through bore and in the hydraulic packoff. 
   
   
       40 - 42 . (canceled)