Apparatus and method for separating solid particles from liquids

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 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 means as measured at right angles to the helical flow path decreasing between the upper end and the lower end of said guide means.

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.

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 pump.

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 of 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.