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TEMPORARY CHRISTMAS TREE SOLUTION

IP.com Disclosure Number: IPCOM000249205D
Publication Date: 2017-Feb-09
Document File: 5 page(s) / 29K

Publishing Venue

The IP.com Prior Art Database

Related People

Freeman, Tommie Austin: INVENTOR [+3]

Abstract

Oil and gas wells are typically produced through surface Christmas trees, which are designed to control production from the well and are rated to contain the shut-in pressure at the wellhead. During the life of a well, it may become desirable to perform workover operations, which may cause the shut-in pressure at the wellhead to rise up beyond the rated pressure of the existing Christmas tree for days, weeks or months. Eventually the pressure will decline back below the rated pressure of the Christmas tree again once production has resumed. Changing the existing Christmas tree for a higher-rated working pressure Christmas tree is not an ideal solution, as it involves great amounts of expense, time and labor to kill a well in production, and change the existing Christmas tree for another one.

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TEMPORARY CHRISTMAS TREE SOLUTION

Oil and gas wells are typically produced through surface Christmas trees, which are designed to control production from the well and are rated to contain the shut-in pressure at the wellhead.  During the life of a well, it may become desirable to perform workover operations, which may cause the shut-in pressure at the wellhead to rise up beyond the rated pressure of the existing Christmas tree for days, weeks or months.  Eventually the pressure will decline back below the rated pressure of the Christmas tree again once production has resumed.  Changing the existing Christmas tree for a higher-rated working pressure Christmas tree is not an ideal solution, as it involves great amounts of expense, time and labor to kill a well in production, and change the existing Christmas tree for another one. 

Therefore, there is a need in the oil and gas industry for means to mitigate the temporary pressure rise at the wellhead at times such as after a workover, which does not require the removal of existing wellhead and Christmas tree.  “Workover” can be any of a variety of operations performed on a hydrocarbon wellbore after an initial completion of the hydrocarbon wellbore, such as removal and replacement of production tubing, removal and replacement of the downhole components of an artificial lift system, removal and replacement of one or more downhole packers, or performing operations with respect to the completion (perforations, sand/gravel pack). 

We disclose in this publication the utilization of a temporary Christmas tree solution, which provides a means for communicating with the production tubing directly without the need of removing the existing wellhead or Christmas tree from the well, nor the need of killing the well or swabbing out the higher-rated tree afterwards.  Instead of changing to a higher-rated tree, the utilization of the temporary Christmas tree solution allows shut-in pressure to decline naturally back below the rated pressure of the existing Christmas tree and wellhead, starting from which point the existing lower-rated Christmas tree could be used for the reminder of the well life. 

More specifically, the temporary Christmas tree solution isolates the existing Christmas tree at the wellhead  (referred to below as “permanent Christmas tree”), for example, at a flow-back period, when the well pressure is higher than the rated pressure of the permanent Christmas tree, by allowing hydrocarbon to be produced through the temporary Christmas tree and its associated valves, etc., and well pressure to naturally decline until the pressure in the wellbore is within the rated pressure of the permanent Christmas tree. 

One type of device which can be used for the temporary Christmas tree solution is wellhead isolation tools.  For simplicity and illustrative purposes, the principles of the present invention are described below by referring mainly to exemplary embodiments as shown in FIGURE...