Integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress

Patent metadata

Field	Value
Publication number	US-9921202-B2
Application number	US-201515110039-A
Country	US
Kind code	B2
Filing date	Apr 20, 2015
Priority date	Mar 9, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

An integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress, including: a true triaxial stress loading experimental frame, a loading system and a monitoring system. The true triaxial stress loading experimental frame and the loading system are connected by oil pipes; the monitoring system is connected to the true triaxial stress loading experimental frame and the loading system by signal lines; the true triaxial stress loading experimental frame comprises a main experimental bench and six flat jacks; a loading cavity for test block is equipped in the main experimental bench; the six flat jacks are set in the loading cavity; and a space of regular hexahedron is formed by the six flat jacks.

First claim

The invention claimed is:

1. An integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress, comprising:
a true triaxial stress loading experimental frame, a loading system and a monitoring system, wherein:
the true triaxial stress loading experimental frame and the loading system are connected by oil pipes;
the monitoring system is connected to the true triaxial stress loading experimental frame and the loading system by signal lines;
the true triaxial stress loading experimental frame comprises a main experimental bench and six flat jacks;
a loading cavity for a test block is equipped in the main experimental bench;
the six flat jacks are set in the loading cavity; and
a space of a regular hexahedron is formed by the six flat jacks.

2. The integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress according to claim 1 , wherein:
the main experimental bench comprises a baseplate, an upper cover plate, displacement restricting steel columns, a caging device, an annulus steel ring and arc-shaped subplates;
the upper cover plate and the baseplate are positioned at the two ends of the annulus steel ring;
the upper cover plate and the baseplate are fitted together by the displacement restricting steel columns;
the number of the arc-shaped subplates is four, the arc-shaped subplates are arranged uniformly in the annulus steel ring; and
the four arc-shaped subplates contact with the four side surfaces of the regular hexahedron.

3. The integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress according to claim 2 , wherein:
the loading system comprises a six-channel hydraulic-pressure stabilizer controlled loading system and a four-channel electro-hydraulic servo controlled loading system;
the six-channel hydraulic-pressure stabilizer controlled loading system and the four-channel electro-hydraulic servo controlled loading system are connected with the true triaxial stress loading experimental frame by oil pipes;
the four-channel electro-hydraulic servo controlled loading system is connected to the true triaxial stress loading experimental frame by a four-channel oil-water transition supercharger; and
the six-channel hydraulic-pressure stabilizer controlled loading system is connected to the true triaxial stress loading experimental frame by a flow divider.

4. The integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress according to claim 3 , wherein:
the flow divider comprises three oil pipes on the inlet side and six oil pipes on the outlet side;
each oil inlet pipe is connected with two oil outlet pipes;
the flow divider is positioned in a flow divider case;
three oil inlet holes exist on one side of the flow divider case, and six oil outlet holes exist on the other side of the flow divider case;
the flow divider comprises an upper cover; and
the flow divider comprises an oil draining valve at the bottom.

5. The integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress according to claim 3 , wherein:
the monitoring system comprises a data processor, pressure sensors and a deformation monitoring system;
the pressure sensors and deformation monitoring system are connected with the data processor by signal lines;
three pressure sensors are installed on the flow divider;
the deformation monitoring system comprises 24 displacement sensors;
the displacement sensors are mounted in the arc-shaped subplates of the flat jacks;
the lines of the displacement sensors are placed in grooves on the side surface of the arc-shaped subplates and gathered to the upper surface of the arc-shaped subplates; and
the displacement sensors are connected with data lines by quick connectors, the female connectors of which are installed on the upper surface of the arc-shaped subplates.

6. The integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress according to claim 1 , further comprising a hydrofracturing system under true triaxial stress, wherein:
the hydrofracturing system under true triaxial stress comprises a similar simulation material casting system with naked borehole, a rock borehole sealing system, a bending hole packer and an independent multi-hole fracturing system;
the similar simulation material casting system, the rock borehole sealing system, the bending hole packer and the independent multi-hole fracturing system are set in parallel;
the similar simulation material casting system includes a round bar and a string wrapped on one end of the bar;

the rock borehole sealing system comprises O-rings and sealant;
the bending hole packer includes a vertical section without fracturing holes and an inclined section with fracturing holes, to simulate hydraulic fracturing under heterotropic stress field; and
the independent multi-borehole fracturing system includes a set of molds with a cover plate of multi-borehole and a caging device, by which hydrofracturing controlled by as many as five independent boreholes can be conducted.

7. The integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress according to claim 1 , further comprising a seepage and gas displacement system under true triaxial stress, wherein:
the seepage and gas displacement system under true triaxial stress includes an upper seepage plate and a bottom seepage plate;
seepage orifices are arrayed on the upper and bottom seepage plates;
the upper seepage plate comprises a water inlet and a fracturing orifice;
the lower seepage comprises a water outlet; and
the interstice between the seepage and gas displacement system under true triaxial stress and the test block is cast by sealant.

8. The integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress according to claim 1 , further comprising a water jet slotting system, wherein the water jet slotting system is connected with the true triaxial stress loading experimental frame to conduct water jet slotting experiments.

9. The integrated experimental system of hydrofracturing, water jet slotting, seepage and gas displacement under true triaxial stress according to claim 8 , wherein:
the water jet slotting system comprises an electromechanical control cabinet, a high pressure pump control cabinet and a water jet slotting device;
the water jet slotting system comprises a rotary motor, a traction motor, a baseplate, two guide rails, a drill pipe, two axial bearings, a propulsion thread rod, a high pressure rotating joint, two sliding blocks and a support frame;
the guide rails are fixed on the support frame;
the baseplate is connected with the guide rails by two sliding blocks;
the drill pipe is fixed on the baseplate by the axial bearings;
two belt pulleys are fitted on the end of the rotating motor and the drill pipe;
the drill pipe is driven to rotate clockwise or anticlockwise by the rotating motor through belt pulleys;
the traction motor is fixed on the guide rails;
the propulsion thread rod is fixed on the guide rails by two axial bearings;
threads exist on the surface of the propulsion thread rod; and
a belt pulley is fitted on one end of the propulsion thread rod and is connected with the belt pulley on the motor by a belt.

Assignees

• Univ China Mining

Inventors

• Huang Bingxiang

Classifications

• G01L15/00

  Devices or apparatus for measuring two or more fluid pressure values simultaneously · CPC title

• G01N33/24 Primary

  Earth materials (G01N33/42 takes precedence) · CPC title

• G01B21/32

  for measuring the deformation in a solid · CPC title