Method for Transporting Multiphase Fluids

Abstract

A method of transporting multiphase fluids during extraction of said fluids from a well. The method includes first providing a well production apparatus. The well production apparatus includes tubing for carrying a flow of well production fluids. A centre line of the tubing follows a substantially helical path, and the amplitude of the helix is less than or equal to one half of the internal diameter of the tubing. Then, the method includes transporting multiphase fluids along the tubing whilst inducing swirl flow thereof.

1 - 57 . (canceled) 
   
   
       58 . A method of transporting multiphase fluids during extraction of said fluids from a well, comprising:
 providing well production apparatus which comprises:   tubing for carrying a flow of well production fluids, wherein the centre line of the tubing follows a substantially helical path, and the amplitude of the helix is less than or equal to one half of the internal diameter of the tubing;   and transporting multiphase fluids along said tubing whilst inducing swirl flow of said fluids.   
   
   
       59 . A method as claimed in  claim 58 , wherein the tubing has a wall, and wherein there are no helical ridges or grooves in the tubing wall, and no guide vanes extending inwardly from the wall. 
   
   
       60 . A method as claimed in  claim 58 , wherein the well production apparatus comprises an outer casing, the tubing fitting inside the outer casing. 
   
   
       61 . A method as claimed in  claim 60 , wherein the
 outer casing has a central axis and an internal diameter, and wherein the tubing has an external diameter and is contained in an imaginary envelope which extends longitudinally and has a central longitudinal axis, the envelope having a width equal to the swept width of the tubing whereby the envelope defines the lateral space occupied by the tubing, and the width of the envelope being greater than the external diameter of the tubing and being smaller than or equal to the internal diameter of the outer casing.   
   
   
       62 . A method as claimed in  claim 58 , wherein the amplitude of the helical centre line of the tubing is less than or equal to 0.25 of the internal diameter of the tubing. 
   
   
       63 . A method as claimed in  claim 58 , wherein the amplitude of the helical centre line of the tubing is less than or equal to 0.15 of the internal diameter of the tubing. 
   
   
       64 . A method as claimed in  claim 58 , wherein the helical centre line of the tubing has a helix angle which is less than or equal to 250. 
   
   
       65 . A method as claimed in  claim 58 , wherein the helical centre line of the tubing has a helix angle which varies along the length of the apparatus. 
   
   
       66 . A method as claimed in  claim 58 , wherein the helical centre line of the tubing has an amplitude which varies along the length of the apparatus. 
   
   
       67 . A method as claimed in  claim 58 , comprising a number of separate lengths of tubing with a helical centre line along the length of the apparatus. 
   
   
       68 . A method as claimed in  claim 58 , wherein the well production apparatus comprises said tubing used as a riser, and multiphase fluids are transported up the riser whilst having swirl flow of said fluids induced in the riser. 
   
   
       69 . A method as claimed in  claim 58 , wherein the well production apparatus comprises said tubing used below a well head, and multiphase fluids are transported along said tubing whilst having swirl flow of said fluids induced in the tubing. 
   
   
       70 . A method as claimed in  claim 58 , wherein the tubing is selected from the group consisting of a flow line, subsea tubing, and surface tubing. 
   
   
       71 . A method as claimed in  claim 58 , wherein the tubing, the centre line of which follows a substantially helical path, is a helical first tubing portion, and wherein the well production apparatus has a second tubing portion downstream of the helical first tubing portion;
 and the method further comprising:   continuing said swirl flow for a distance downstream of said helical first tubing portion in said second tubing portion whilst reducing said swirl flow.   
   
   
       72 . A method as claimed in  claim 71 , comprising:
 providing a plurality of separate helical tubing portions along the length of the apparatus, each helical tubing portion having a centre line which follows a substantially helical path; and   inducing swirl flow of the multiphase fluids in each of said separate helical tubing portions.