Spiral Sand-Removal Gas Anchor Structure

The spiral sand-removal gas anchor is assembled from an upper joint, coupling, outer tube, central tube, spiral blades, and a lower joint.

Spiral Gas Anchor Structural Diagram

1. Upper Joint 2. Coupling 3. Outer Tube 4. Central Tube 5. Helical Blade 6. Lower Joint

1. Operating Principle

When the spiral sand-control gas anchor is operating, it is connected to the lower section of the pumping unit's tubing string, enabling the separation of water, gas, and sand into three distinct phases. The separated liquid phase is then conveyed to the upper pumping unit, while the accompanying gas is vented into the annulus between the tubing and casing. Meanwhile, the solid-phase sand particles settle down into the tailpipe and the artificial bottom of the well. The three-phase separation process, the extraction process, as well as the sand-removal and gas-discharge processes are described below:

2.1 Three-phase separation process of water, gas, and sand: As the plunger of the pumping unit begins to move upward from the bottom dead center, a region of relatively low pressure forms in the annular space between the central tube, the umbrella-shaped helical guide vanes, and the inner wall of the outer tube, causing fluid from the wellbore to begin flowing...

The fluid enters the annular space of the gas-sand anchor through the inlet screen holes, where it undergoes filtration. During the upward stroke of the pumping unit, the suction action induces a spiral, downward-flowing motion of the fluid within the helical annular space. As this occurs, the gas, liquid, and solid phases—due to their differing densities—are separated to varying degrees via centrifugal forces. With the continuous downward spiral movement, the solid phase gradually deposits along the inner wall of the outer tube, while the gas phase progressively accumulates against the outer wall of the central tube. Meanwhile, the liquid phase gathers in an annular space extending from the inner wall of the outer tube all the way to a specific distance from the outer wall of the central tube. At this point, the three-phase separation is complete.

2.2 Oil Pumping Process

After being separated and filtered through the spiral, the relatively pure fluid exits from the trailing edge of the spiral guide vanes, enters the central tube via its lower end, and finally flows into the pumping unit through the central hole of the upper connector.

2.3 Sand-Discharge Process

After spiral separation, the sand particles adhere tightly to the inner wall of the outer tube. As they exit the trailing edge of the spiral guide vanes, they enter the annular cavity between the outer and central tubes due to inertia, and then gradually settle into the surrounding area.

3. Specifications and Parameters

Specification: LQ-89 Spiral Gas Anchor

Parameters: Maximum outer diameter: φ108

Tool total length: 5000 mm

Threaded connections at both ends: 2 7/8” EUE female coupling on the upper end; 2 7/8” EUE male thread on the lower end

Inner diameter: 22–25 mm

4. Instructions for Use

4.1 Under normal circumstances, connect one oil pipe between the pump and the device to serve as a buffer. At the lower end of the gas anchor, attach 1–2 oil pipes, sealing off their lower ends to create pockets, which helps in the deposition of sand and other sediments.

4.2 Before lowering the new device into the well, carefully inspect all connection threads; if any are loose, simply tighten them. Also, ensure that all fluid inlet ports are free of obstructions.

4.3 When connecting the various parts of the separation device itself, or when attaching it to the downhole tubing string, ensure that threads, fluid inlet ports, and other components are not damaged.

4.4 When pulling the pump for作业 and removing the separation device, it must be thoroughly cleaned both inside and out, and inspected according to the requirements for a new separation device before proceeding with further downhole operations.

4.5 During the transportation of the separation device, protective threads must be added at both ends and securely wrapped to prevent dirt and debris from entering.