Pressure regulator for fluid hammer reduction

Abstract

A method of reducing hydraulic shock in a BOP system including a pressure regulator having an input port and an output port, and a regulator piston that moves between an open and a closed position based on a change in hydraulic pressure applied to the regulator piston via a pilot port. The method includes initiating a function, and monitoring the state of the function as it is carried out to predict when the function nears the end of its cycle. The method also includes, when the function reaches a predetermined state, adjusting the hydraulic pressure on the regulator piston via the pilot port to gradually move the regulator piston between the open to the closed position to reduce fluid flow through the fluid path in a controlled manner to reduce hydraulic shock.

What is claimed is: 
     
         1 . A method of reducing hydraulic shock in a BOP system, The BOP system including a pressure regulator having an input port and an output port, and a regulator piston that moves between an open and a closed position based on a change in hydraulic pressure applied to the regulator piston via a pilot port, the open position creating a fluid path between the input port and the output port so that fluid can flow therebetween, and the closed position severing the fluid path, the method comprising:
 (a) initiating a function;   (b) monitoring the state of the function as it is carried out to predict when the function nears the end of its cycle;   (c) transmitting information about the state of the function to a controller that controls the amount of hydraulic pressure applied to the regulator piston via the pilot port;   (d) determining when the function reaches a predetermined state prior to the end of its cycle; and   (e) when the function reaches the predetermined state, adjusting the hydraulic pressure on the regulator piston via the pilot port to begin moving the regulator piston toward the closed position.   
     
     
         2 . The method of  claim 1 , wherein the regulator piston moves toward the closed position by reducing the amount of hydraulic pressure applied to the regulator piston via the pilot port. 
     
     
         3 . The method of  claim 1 , wherein step (e) further comprises controlling the amount of hydraulic pressure applied through the pilot port using a valve. 
     
     
         4 . The method of  claim 1 , wherein the function is a function selected from the group consisting of a valve and a blowout preventer ram. 
     
     
         5 . The method of  claim 1 , further comprising the step of determining the pressure in a regulator housing adjacent the inlet port via a pressure read-back port. 
     
     
         6 . The method of  claim 1 , wherein the controller processes the information about the state of the function, and employs an algorithm to determine when to begin adjusting the hydraulic pressure on the regulator piston. 
     
     
         7 . The method of  claim 1 , wherein the pressure in the outlet port is substantially equal to the pressure in the pilot port. 
     
     
         8 . A method of opening and closing a fluid flow path through a pressure regulator, the method comprising:
 (a) providing an input port, and output port, and a pilot port at discrete locations on a housing of the pressure regulator;   (b) providing a regulator piston within the housing, the regulator piston movable within the housing along a longitudinal axis of the regulator piston, and having a hollow portion that allows fluid flow through the regulator piston, the regulator piston in an open position when the hollow portion at least partially aligns with the input and output ports so that fluid flows between the input and output ports, and in a closed position when the hollow portion is not aligned with the input and output ports;   (c) controlling movement of the regulator piston between open and closed positions by adjustment of hydraulic pressure on the regulator piston, such hydraulic pressure provided via the pilot port.   
     
     
         9 . The method of  claim 8 , further comprising the steps of:
 (d) initiating a function;   (e) monitoring the state of the function as it is carried out to predict when the function nears the end of its cycle;   (f) when the function reaches the predetermined state, adjusting the hydraulic pressure on the regulator piston via the pilot port to begin moving the regulator piston toward the closed position.   
     
     
         10 . The method of  claim 9 , further comprising the steps of:
 (g) transmitting information about the state of the function to a controller that controls the amount of hydraulic pressure applied to the regulator piston via the pilot port;   (h) determining when the function reaches a predetermined state prior to the end of its cycle.   
     
     
         11 . The method of  claim 9 , wherein step (f) further comprises controlling the amount of hydraulic pressure applied through the pilot port using a valve. 
     
     
         12 . The method of  claim 9 , wherein the function is a function selected from the group consisting of a valve and a blowout preventer ram. 
     
     
         13 . The method of  claim 9 , further comprising the step of determining the pressure in the housing adjacent the inlet port via a pressure read-back port. 
     
     
         14 . The method of  claim 10 , wherein the controller processes the information about the state of the function, and employs an algorithm to determine when to begin adjusting the hydraulic pressure on the regulator piston. 
     
     
         15 . The method of  claim 8 , wherein the pressure in the outlet port is substantially equal to the pressure in the pilot port. 
     
     
         16 . A hydraulic shock reducing pressure regulator for controlling a function on a BOP stack, comprising:
 a housing having an input port, an output port, and a pilot port;   a regulator piston having a hollow portion and surrounded by the housing, the regulator piston movable within the housing between an open position and a closed position, the regulator piston in the open position when the hollow portion connects the input port with the output port to allow pressure communication between the input port and the output port, and in the closed position when the hollow portion is misaligned from either the input port or the output port or both so that there is no pressure communication between the input port and the output port;   a portion of the regulator piston in pressure communication with the pilot port so that controlled changes in pressure in the pilot port move the regulator piston between the open position and the closed position and vice versa.   
     
     
         17 . The pressure regulator of  claim 16 , further comprising a controller that receives data about the state of the function controlled by the pressure regulator, and that gradually adjusts the position of the regulator piston between the open and the closed position as the function nears completion to reduce hydraulic shock. 
     
     
         18 . The pressure regulator of  claim 16 , wherein the function is a function selected from the group consisting of a valve and a blowout preventer ram. 
     
     
         19 . The pressure regulator of  claim 16 , wherein the pressure in the outlet port is substantially equal to the pressure in the pilot port. 
     
     
         20 . The pressure regulator of  claim 17 , further comprising a pressure read-back port that measures pressure in the housing adjacent the inlet port and sends data about such pressure to the controller.