METHODS FOR INTRODUCING ISOLATORS INTO OIL AND GAS AND LIQUID PRODUCT PIPELINES

Abstract

A method for separating two or more different gases that are being transported in a pipeline is described. A slug of inert gas, particularly nitrogen is introduced between the two or more different gases to replace the isolators that have been traditionally used. This slug of inert gas will assist in more efficiently transporting the gas while reducing the problems associated with isolators. There is further disclosed a method for separating and transporting at least two liquid products such as two different crudes or diesel and gasoline in a pipeline.

Claims

1. A method for transporting at least two gas products through a pipeline, the improvement comprising introducing a slug of inert gas between the at least two gas products.

2. The method as claimed in claim 1 wherein the at least two gas products are selected from the group consisting of natural gas, air, oxygen, synthesis gas and ethane.

3. The method as claimed in claim 1 wherein the inert gas is selected from the group consisting of nitrogen and argon.

4. The method as claimed in claim 1 wherein the at least two gas products are the same gas.

5. The method as claimed in claim 1 wherein the at least two gas products are different gases.

6. The method as claimed in claim 1 wherein the inert gas slug is introduced during flow of the at least two gas products.

7. The method as claimed in claim 1 wherein the inert gas slug is introduced prior to transporting of the at least two gas products.

8. The method as claimed in claim 1 wherein the inert gas slug is introduced into the pipeline through a compressor or pressurized cylinder with a venturi nozzle.

9. A method for transporting at least two gas products through a pipeline comprising introducing a slug of nitrogen between the at least two gas products.

10. The method as claimed in claim 9 wherein the at least two gas products are selected from the group consisting of natural gas, air, oxygen, synthesis gas and ethane.

11. The method as claimed in claim 9 wherein the at least two gas products are the same gas.

12. The method as claimed in claim 9 wherein the at least two gas products are different gases.

13. The method as claimed in claim 9 wherein the slug of nitrogen is introduced during flow of the at least two gas products.

14. The method as claimed in claim 9 wherein the slug of nitrogen is introduced prior to transporting of the at least two gas products.

15. The method as claimed in claim 9 wherein the slug of nitrogen is introduced into the pipeline through a compressor or pressurized cylinder with a venturi nozzle.

16-23. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 is a schematic of a pipeline showing an isolator separating nitrogen and air in a pipeline.

[0021] FIG. 2 is a schematic showing two different gases passing through a pipeline.

[0022] FIG. 3 is a schematic showing several different gases separated by isolators in a pipeline.

[0023] FIG. 4 is a schematic showing several different gases being separated by nitrogen slugs in a pipeline.

DETAILED DESCRIPTION OF THE INVENTION

[0024] FIG. 1 shows an isolator that is firstly placed at the entrance of a pipeline before pumping the nitrogen. Nitrogen (N2) is fed in the flow direction indicated by the arrow into the pipeline 10. Air is present downstream from the N2 and is separated by an isolator A.

[0025] The nitrogen flow pushes the isolator A forward. Since the terrain through which pipelines are pass can be quite uneven from mountains to deserts to rough grounds and river deltas, the undulations make passing the isolator A through the pipeline 10 much more difficult. In larger diameter pipelines, the costs for isolators can be double that of smaller diameter pipelines. Further isolator seals can fail due to wear as well as getting stuck in the pipeline.

[0026] In the methods of the present invention, the isolator is replaced with inert nitrogen gas. The use of nitrogen gas rather than a physical isolator can result in saving as well as avoid some of the difficulties with undulations in the pipelines while eliminating the risks involved in isolators getting stuck or failing.

[0027] FIG. 2 shows the same pipeline 10 with a flow of gas in the direction of the arrow whereby nitrogen (N2) is used to replace the isolator. In this process the gas mixture length becomes a key parameter in determining the displacement of nitrogen.

[0028] FIG. 3 shows a pipeline 20 which contains a number of different products A, B, C and D flowing in the direction of the arrow. The isolators 1, 2 and 3 are shown separating these different products.

[0029] FIG. 4 shows the improvement to the isolator schematic described in FIG. 3. A pipeline 30 has a series of different products A, B, C and D travelling in the direction of the arrow. In this embodiment a nitrogen slug N2 will be placed between each of the different products A, B, C and D to act as an isolator thereby keeping the products at their proper concentration and specification for subsequent delivery and/or removal from the pipeline 30.

[0030] While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims in this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the invention.