Apparatus and method for separating solid particles from liquids

Abstract

Apparatus and method for separating solid particles from well fluids in the bore hole including a separator separation device (34) adjacent the lower end of a tubing string (14) positioned within a perforated casing (10). The separator device (34) includes concentric tubular members (44, 46) defining an annulus (60) therebetween. A spiral guide (62) is positioned in the annulus (60) about the inner tubular member (44) below perforations (54) in the outer tubular member (44) and extends about the inner tubular member (46) for around a complete turn or 360 degrees. A helical motion is imparted to the well fluids received through the perforations (54) and solid particles settle downwardly within the vortex or swirl chamber (79) below the inner tubular member (46). The liquid separated from the solid particles is pump by a downhole pump (18) upwardly through the inner tubular member (46).

What is claimed is: 
     
       1. A downhole tubing string adapted to be positioned within a well bore for removing liquids from the well and comprising: a tubular body extending within the well bore; and   a separation device .[.connected to.]. .Iadd.supported from .Iaddend.said tubular body adjacent the lower end thereof for separating solid particles from liquids so that the separated solid particles are not forced to a surface location;   said separation device including;   an outer tubular member and a concentric inner tubular member defining an annulus between said inner and outer members;   fluid inlet means for said outer tubular member in fluid communication with said annulus;   means blocking fluid flow upwardly from said annulus; and   a spiral guide in said annulus between said tubular members and below said fluid inlet means for directing solid particles received from said fluid inlet means downwardly in a helical motion for settling of said solid particles below said inner tubular member with the separated liquid flowing upwardly from the lower end of said inner tubular member through said inner tubular member to a surface location, the cross sectional area of the helical path along the spiral guide as measured at right angles to the helical flow path decreasing between the upper end and the lower end of said guide thereby to provide a relatively smooth flow at a progressively increasing velocity.   
     
     
       2. A downhole tubing string as set forth in claim 1 wherein said spiral guide extends about said inner tubular member for at least around 360 degrees. 
     
     
       3. A downhole tubing string set forth in claim 1 wherein said spiral guide has an upper helical surface for directing the liquid and entrained solid particles with the upper surface adjacent the upper end of said guide being at an angle greater than around 30 degrees with respect to the transverse axis of the tool, and the upper surface adjacent the lower end or said guide being at an angle less than around 25 degrees with respect to the transverse axis of the tool thereby to provide a relatively smooth helical motion. 
     
     
       4. A downhole tubing string as set forth in claim 3 wherein the inner surface of the lower end portion of said inner tubular member defines an inner surface tapered at an angle of between around 5 degrees and 20 degrees with respect to the longitudinal axis of the tool thereby to provide a relatively smooth flow entrance to the inner tubular member for the separated liquid. 
     
     
       5. A downhole tubing string as set forth in claim 1 wherein said inner tubular member has a lower end portion below the lower end of said spiral guide of a length at least equal to around the outer diameter of said inner tubular member for continuing the downward swirling action of the liquid and entrained solid particles. 
     
     
       6. A downhole tubing string as set forth in claim 1 wherein said outer tubular member has an upper annular shoulder thereon, and said inner tubular member has an upper annular flange supported on said shoulder. 
     
     
       7. A downhole tubing string as set forth in claim 1 wherein said inner tubular member has a central bore therethrough defining a passage for the upward flow of liquids and a separate gas passage therein for the upward flow of gas, said gas passage being in fluid communication adjacent its lower end with said annulus for the entry of gas from the annulus. 
     
     
       8. A downhole tubing string as set forth in claim 7 wherein a gas outlet in fluid communication with said gas passage in said inner tubular member extends through said outer tubular member and upwardly therefrom in the annulus between said casing and said tubing string. 
     
     
       9. A downhole tubing string as set forth in claim 1 wherein a perforated casing is provided in said well bore; a pump is positioned in said tubing string above said separation device; and   a packer is positioned in the annulus between the casing and the tubing string above said separation device.   
     
     
       10. A downhole tubing string as set forth in claim 1 wherein a perforated casing is provided in said well bore;   a pump is positioned in said tubing string; and   a packer is positioned in the annulus between the casing and the tubing string below said separation device.   
     
     
       11. In a downhole tool string positioned within a well bore and having a tubular body for removing fluids from the well; a separation device .[.connected to.]. .Iadd.supported from .Iaddend.said tubular body adjacent the lower end thereof for separating solid particles from liquids so that the separated solid particles are not removed from the well; said separation device comprising: an outer tubular member and a concentric inner tubular member defining an annulus between said inner and outer members;   a fluid inlet passage in said outer tubular member extending to said annulus;   means blocking fluid flow upwardly from said annulus; and   guide means in said annulus between said tubular members and below said fluid inlet passage for directing solid particles received from said fluid inlet passage downwardly in a helical motion for settling of said solid particles below said inner tubular member with the separated liquid flowing upwardly from the lower end of said inner tubular member through said inner tubular member to a surface location, the cross sectional area of the helical path along the .[.spiral.]. .Iadd.guide .Iaddend.means as measured at right angles to the helical flow path decreasing between the upper end and the lower end of said guide means.   
     
     
       12. In a downhole tool string as set forth in claim 11; said guide means including a single spiral guide having an upper helical surface for directing the liquid and entrained solid particles downwardly in a helical motion.   
     
     
       13. In a downhole tool string as set forth in claim 12; said inner tubular member having a lower end portion below the lower end of said spiral guide of a length at least equal to around the outer diameter of said inner tubular member for continuing the downward swirling action of the liquid and entrained solid particles.   
     
     
       14. In a tool string having a tubular body for removing fluids from a fluid reservoir; a separation device connected to said tubular body adjacent the lower end thereof for separating solid particles from liquids so that the separated solid particles are not removed from the fluid reservoir; said separation device comprising: an outer tubular member and a concentric inner tubular member defining an annulus between said inner and outer members;   a fluid inlet passage in said outer tubular member extending to said annulus and restricting large solid particles from entering said annulus through said fluid inlet passage;   means blocking fluid flow upwardly from said annulus; and   spiral guide means in said annulus between said tubular members and below said fluid inlet passage for directing solid particles received from said fluid inlet passage downwardly in a helical motion for settling of said solid particles below said inner tubular member with the separated liquid flowing upwardly from the lower end of said inner tubular member through said inner tubular member to a separate location; said spiral guide means extending about said inner tubular member for at least around 360 degrees, the cross sectional area of the helical path along the spiral means as measured at right angles to the helical flow path decreasing between the upper end and lower end of said guide means.   
     
     
       15. In a tool string as set forth in claim 14 wherein said spiral guide means has an upper helical surface for directing the liquid and entrained solid particles with the upper surface adjacent the upper end of said guide means being at an angle greater than around 30 degrees with respect to the transverse axis of the tool string; and the upper surface adjacent the lower end of said guide means being at an angle less than around 25 degrees with respect to the transverse axis of the tool thereby to provide a relatively smooth helical motion. 
     
     
       16. In a downhole tubing string having a tubular body adapted to be positioned within a well bore for removing liquids from the well and comprising: a separation device connected to said tubular body adjacent the lower end thereof for separating solid particles from liquids in well fluids so that the separated solid particles are not forced to a surface location; said separation device having an outer tubular member and a concentric inner tubular member defining an annulus therebetween, a fluid inlet passage in said outer tubular member extending to said annulus, and spiral guide means in said annulus below said fluid inlet passage for directing well fluids received from said fluid inlet passage downwardly in a helical motion for separation of the solid particles from the liquids;   a reciprocating rod-type pump in the tubular body above the separation device; and   gas accumulator means in an intermediate section of the tubular body between the reciprocating pump and the separation device relative to the flow path of said well fluids for the collection of gas therein and being in fluid communication with said separation device, said gas accumulator means permitting expansion of gas in said intermediate section on the upward stroke of the reciprocating pump and compressing gas on the downward stroke of the reciprocating pump, the compressed gas on the upward stroke of said pump permitting well fluids through said separation device thereby to provide a generally continuous flow of well fluids through said separation device during the upward and downward strokes of said reciprocating.   
     
     
       17. A method for separating solid particles from liquids in well fluids of a bore hole for the pumping of the separated liquids from the bore hole; said method comprising the following steps: providing a separation device adjacent the lower end of a downhole pipe string with the separation device having concentric inner and outer tubular members for defining an annulus therebetween;   providing a fluid inlet in said outer tubular member in fluid communication with said annulus to permit the flow of well fluids with entrained solid particles through said fluid inlet into said annulus;   providing guide means in said annulus below said fluid inlet extending about said inner tubular member in a downward spiral path;   directing said well fluids from said fluid inlet along said guide means in a spiral path about said inner tubular member to impart a helical motion to said well fluids for movement to a separation chamber below said inner tubular member;   collecting solid particles separated from said well fluids adjacent the bottom of said separation chamber;   pumping the liquid in said well fluids separated from said solid particles upwardly through said inner tubular member;   providing a separate gas passage for said inner tubular member in fluid communication with said annulus and extending upwardly to a surface location;   removing gas from said well fluids at a position adjacent the lower end or said inner tubular member for flow into said gas passage for removal from said bore hole; and   providing check valve means in said separate gas passage to block a reverse flow of gas from said inner tubular member for maintaining an amount of gas below said check valve means.