System and methodology for pressure compensation

Abstract

A technique facilitates pressure compensation with respect to a tool while also limiting detrimental influx of contaminants. A pressure compensation mechanism comprises a fluid trap chamber which is in fluid communication with a clean fluid chamber via a connector passage. The fluid trap chamber also is in communication with an external pressure region via an inlet passage. The connector passage is located such that a potentially contaminating fluid, e.g. water, entering via the inlet passage is isolated from the clean fluid chamber. The connector passage remains isolated regardless of whether the pressure compensation mechanism is in a vertical operational position or a deviated operational position.

1 . A system for pressure compensation, comprising:
 a well string having a well tool with a tool mechanism which operates in oil contained within an oil chamber, the well tool further comprising:
 a pressure compensation mechanism having a fluid trap chamber in fluid communication with the oil chamber via a connector passage, the fluid trap chamber also being in communication with an external pressure region via an inlet passage, 
 the connector passage being located such that fluids which enter the fluid trap chamber via the inlet passage and are heavier than the oil collect at regions of the fluid trap chamber separated from the connector passage regardless of whether the well tool is in a vertical operational position or a deviated operational position. 
   
     
     
         2 . The system as recited in  claim 1 , wherein the pressure compensation mechanism further comprises a particle filter positioned to block flow of particulates through the inlet passage. 
     
     
         3 . The system as recited in  claim 1 , wherein the fluid trap chamber is in the shape of a cylinder. 
     
     
         4 . The system as recited in  claim 3 , wherein the connector passage is in fluid communication with the fluid trap chamber at a central axis of the cylinder. 
     
     
         5 . The system as recited in  claim 4 , wherein the central axis is vertical when the well tool is in the vertical operational position. 
     
     
         6 . The system as recited in  claim 4 , wherein the central axis is horizontal when the well tool is in the deviated operational position and the deviated operational position is horizontal. 
     
     
         7 . The system as recited in  claim 1 , wherein the inlet passage places the fluid trap chamber in communication with external pressure within a wellbore along an exterior of the well tool. 
     
     
         8 . The system as recited in  claim 1 , wherein the fluid trap chamber comprises a central region separated from an outer annular region. 
     
     
         9 . The system as recited in  claim 8 , wherein the pressure compensation mechanism further comprises a baffle in the fluid trap chamber. 
     
     
         10 . A method for pressure compensation, comprising:
 positioning a tool mechanism of a tool in an oil chamber for operation in oil contained in the oil chamber;   coupling the oil chamber with a fluid trap chamber via a connector passage;   locating the connector passage such that water entering the fluid trap chamber does not reach the connector passage regardless of whether the tool is in a vertical operational position or a deviated operational position; and   coupling the fluid trap chamber with an external region at an external pressure via an inlet passage to enable pressure compensation of the oil chamber via a pathway from the external region to the oil chamber along the inlet passage, the fluid trap chamber, and the connector passage.   
     
     
         11 . The method as recited in  claim 10 , further comprising preventing flow of particulates through the inlet passage via a particulate filter. 
     
     
         12 . The method as recited in  claim 10 , further comprising forming the fluid trap chamber as a cylinder. 
     
     
         13 . The method as recited in  claim 12 , further comprising joining the connector passage with the cylinder at a central axis of the cylinder. 
     
     
         14 . The method as recited in  claim 10 , further comprising forming the fluid trap chamber with a central region separated from an annular region. 
     
     
         15 . The method as recited in  claim 14 , wherein forming comprises forming the central region with a conical shape. 
     
     
         16 . The method as recited in  claim 10 , further comprising connecting the tool into a well string. 
     
     
         17 . The method as recited in  claim 16 , wherein coupling comprises compensating for a pressure differential between the oil chamber and a wellbore region external to the tool. 
     
     
         18 . A system, comprising:
 a pressure compensation mechanism having a fluid trap chamber, the fluid trap chamber being in fluid communication with a clean fluid chamber via a connector passage and with an external pressure region via an inlet passage, the connector passage being located such that water entering via the inlet passage is isolated from the clean fluid chamber when the pressure compensation mechanism is in a vertical operational position and when the pressure compensation mechanism is in a horizontal operational position; and   a tool mechanism of a well tool, the tool mechanism being positioned for operation in the clean fluid chamber.   
     
     
         19 . (canceled) 
     
     
         20 . The system as recited in  claim 19 , wherein the connector passage, the fluid trap chamber, and the inlet passage form a pressure pathway between the clean fluid chamber and an external wellbore region.