Novel coil-tubing ram blowout preventer

Abstract

A coil-tubing ram blowout preventer is disclosed that includes a ram block and ram-block cavity each having a D-shaped cross section. The flat portion of the ram block's “D” corresponds to the flat portion of the cavity's “D” to prevent rotation of the ram block within the ram-block cavity. The ram block may be configured with selectively replaceable seals, slips, or shear blades to allow easy configuration of the ram block for various sizes of tubing. The shear blades may include a sealing component on one surface of the blade such that paired shear-ram-blocks may create two distinct sealing points when each sealing component engages the other blade when the shear rams are closed.

The invention claimed is: 
     
         1 . A coil-tubing blowout preventer comprising:
 (a) a body having a first ram-block cavity defined by a cylindrical surface having a cross section that is substantially circular but for a single flat portion having a length less than one-half of the perimeter of the cross section; and   (b) a first ram block having a cross section that is substantially circular but for a single flat portion having a length less than one-half of the perimeter of the cross section;   (c) wherein the flat portion of the ram-block cavity corresponds to the flat portion of the ram block.   
     
     
         2 . The coil-tubing blowout preventer of  claim 1  further comprising a second ram block wherein:
 (a) the first ram block includes a first shear blade having a first surface and a first elastomeric material bonded to the first shear blade; 
 (b) the second ram block includes a second shear blade having a second surface and a second elastomeric material bonded to the second shear blade; 
 (c) the first elastomeric material is configured to engage the second surface when the first and second ram blocks are in the closed position and thereby form a first seal between the first shear blade and the second shear blade; and 
 (d) the second elastomeric material is configured to sealingly engage the first surface when the first and second ram blocks are in the closed position and thereby form a second seal between the first shear blade and the second shear blade. 
 
     
     
         3 . The coil-tubing blowout preventer of  claim 1  wherein the first ram block includes a body and an elastomeric component that is configured to engage the outside surface of tubing to thereby form a seal between the body and the tubing and wherein the elastomeric component may be selectively removed from or inserted into the body. 
     
     
         4 . The coil-tubing blowout preventer of  claim 1  wherein the first ram block includes a body and a toothed or scored component that is configured to engage the outside surface of tubing to thereby hold the tubing in place relative to the body and wherein the toothed or scored component may be selectively removed from or inserted into the body. 
     
     
         5 . The coil-tubing blowout preventer of  claim 1  wherein the first ram block includes a body and shear blade that is configured to shear through tubing and wherein the shear blade may be selectively removed from or inserted into the body.