CN204402458U - The equipment of pollution falls in low pressure and low permeability saturating reservoir coal bed gas well nitrogen foam pressure break - Google Patents

Abstract

The utility model relates to the equipment that pollution falls in a kind of low pressure and low permeability saturating reservoir coal bed gas well nitrogen foam pressure break, it is characterized in that, comprise tank truck, sand tank car, fracturing blender truck, fracturing car, high pressure pipe joint, liquid nitrogen tank car, liquid nitrogen pump vehicle and measuring truck, described tank truck is connected with fracturing blender truck respectively by pipeline with sand tank car, described fracturing blender truck is connected with fracturing car by pipeline, described liquid nitrogen tank car is connected with liquid nitrogen pump vehicle, described fracturing car is connected with high pressure pipe joint respectively by pipeline with described liquid nitrogen pump vehicle, described high pressure pipe joint is extended to shaft bottom along the borehole wall by well head.

Description

Equipment for reducing pollution by nitrogen foam fracturing in low-pressure and low-permeability reservoir coalbed methane wells

technical field

The utility model relates to the technical field of coalbed gas exploration and development, in particular to a technology for reducing pollution by nitrogen foam fracturing of coalbed gas wells in low-pressure and low-permeability reservoirs.

Background technique

Coalbed methane, as an important unconventional natural gas resource, is increasingly valued by countries all over the world. Most of the coalbed methane is stored in the inner surface of coal matrix pores in the state of adsorption, and only a small amount exists in cleats and other fractures in a free state. The output of coalbed methane must go through the process of desorption, diffusion and seepage.

Coal reservoir pressure refers to the pressure of the fluid in the fractures of the reservoir. Generally, the reservoir with a pressure gradient of less than 0.6MPa/hm is called a low-pressure reservoir. The pressure of my country's coal reservoirs is generally low pressure; my country's coalbed methane reserves are 36.8 trillion m3 , low-permeability coalbed methane resources are about 26.5 trillion m3, accounting for 72% of the country's total resources, mainly low-permeability and ultra-low permeability.

In order to increase the production capacity of CBM, artificial stimulation measures are generally taken to improve the physical properties of the reservoir. Hydraulic fracturing technology is widely used in the development of coalbed methane at home and abroad as the main production stimulation measure. However, due to the serious leakage of fracturing fluid, low flowback rate, difficulty in proppant carrying, and short and single fracturing fractures in the active water fracturing process , No reservoir energy enhancement effect and other issues make the stimulation effect unsatisfactory, which also puts forward new and higher requirements for the coal bed gas fracturing process.

Utility model content

In view of the above-mentioned problems, the utility model provides a pollution-reducing equipment for nitrogen foam fracturing of coalbed gas wells in low-pressure and low-permeability reservoirs.

The utility model provides a device for reducing pollution by nitrogen foam fracturing of coalbed gas wells in low-pressure and low-permeability reservoirs, including liquid tank trucks, sand tank trucks, sand mixer trucks, instrument trucks, hydraulic fracturing trucks, high-pressure manifolds, and liquid nitrogen tanks Truck, liquid nitrogen pump truck and instrument truck, liquid tank truck and sand tank truck are connected to sand mixing truck through pipelines, sand mixing truck is connected to hydraulic fracturing truck through pipelines, liquid nitrogen tank truck is connected to liquid nitrogen pump truck, The hydraulic fracturing truck and the liquid nitrogen pump truck are respectively connected to the high-pressure manifold through pipelines, and the high-pressure manifold extends to the bottom of the well through the wellhead along the well wall.

Further, the sand mixing vehicle and the hydraulic fracturing vehicle are respectively connected to the instrument vehicle through signal lines, and the working conditions of the sand mixing vehicle and the hydraulic fracturing vehicle are monitored through the instrument vehicle.

Further, there are more than 3 liquid tank trucks and hydraulic fracturing trucks, and more than 2 liquid nitrogen tank trucks.

Its beneficial effect is:

1. Small pollution. Nitrogen foam fracturing injects much less liquid into the formation than conventional fracturing, and relatively less damage and pollution to the formation than some conventional glue-type fracturing fluids.

2 Filtration reduction, the inherent characteristics of the foam itself, especially in the fracturing process of low-pressure and low-permeability reservoirs, the effect of reducing fluid loss is relatively obvious.

3 Strong sand-carrying ability. When fracturing low-pressure and low-permeability reservoirs, the foam-sand-carrying ratio can be increased to more than 50%, which is much stronger than conventional fracturing fluid. Spread sand evenly in the cracks.

4 Strong seam-making ability, the characteristics of the foam itself, with the assistance of nitrogen, the foam seam will be wider and higher.

5. Easy to flow back. Due to the effect of nitrogen, the effect will be better than that of conventional fracturing in the later stage of spraying and flowback. The amount of flowback is large, which shortens the drainage cycle of fracturing fluid and reduces the damage to the reservoir.

Therefore, the pollution reduction technology of nitrogen foam fracturing is more effective for the reservoir stimulation of CBM wells in low-pressure and low-permeability reservoirs.

Description of drawings

Fig. 1 is a schematic diagram of the equipment structure of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

As shown in Figure 1, a kind of equipment to realize the pollution reduction method of nitrogen foam fracturing of coalbed methane wells in low-pressure and low-permeability reservoirs, including liquid tank trucks, sand tank trucks, sand mixer trucks, instrument trucks, hydraulic fracturing trucks, high-pressure manifolds, liquid The nitrogen tank truck, the liquid nitrogen pump truck and the instrument truck, the liquid tank truck and the sand tank truck are respectively connected to the sand mixer truck through pipelines, the sand mixer truck is connected to the hydraulic fracturing truck through pipelines, and the liquid nitrogen tank truck and the liquid nitrogen pump truck are connected to each other. Connection, the hydraulic fracturing truck and the liquid nitrogen pump truck are respectively connected to the high-pressure manifold through pipelines, and the high-pressure manifold extends to the bottom of the well through the wellhead along the well wall. The sand mixing vehicle and the hydraulic fracturing vehicle are respectively connected to the instrument vehicle through signal lines, and the working conditions of the sand mixing vehicle and the hydraulic fracturing vehicle are monitored through the instrument vehicle. The preferred number of liquid tank trucks and hydraulic fracturing trucks is 3, and the preferred number of liquid nitrogen tank trucks is 2.

At the same time, the utility model provides a method for reducing pollution by nitrogen foam fracturing of coalbed gas wells in low-pressure and low-permeability reservoirs, including the following steps:

(1) Install large fracturing fluid tanks according to the design requirements, prepare water, and mix fluid; the water used for fluid mixing must be clean, with a pH value of 7-7.5, to ensure clean water quality, mechanical impurities less than 1‰, and solid particle size ≤ 50 μm. The finished fracturing fluid should be fully stirred and mixed evenly. When mixing glue, the cycle time of each large tank should not be less than 30 minutes;

(2) Install the 350-type fracturing wellhead, tighten the four corners with wire ropes and fix them with ground anchors;

(3) The fracturing equipment is in place, connected to the high and low pressure pipelines, the high pressure pipeline is connected to double pipelines, the ground high pressure manifold and wellhead pressure test is 35MPa, and the pressure is stabilized for 10 minutes without leakage, it is qualified;

(4) Carry out fracturing construction on the coal seam according to the designed pump injection procedure, the glue discharge rate is 1.4m3/min, the nitrogen discharge rate is 350m3/min, the nitrogen discharge temperature is not lower than 20 degrees Celsius, and the pressure limit is 35MPa during the fracturing process;

(5) Measure the pressure drop for 30 minutes after fracturing;

(6) After measuring the pressure drop, install blowout equipment, perform rapid pressure-controlled blowdown, and closely observe the flowback liquid. If there is sand or coal powder returning, reduce the blowout speed. If there is no sand or coal powder Return, you can increase the spray volume.

Claims (3)

1. the equipment of pollution falls in a low pressure and low permeability saturating reservoir coal bed gas well nitrogen foam pressure break, it is characterized in that, comprise tank truck, sand tank car, fracturing blender truck, fracturing car, high pressure pipe joint, liquid nitrogen tank car, liquid nitrogen pump vehicle and measuring truck, described tank truck is connected with fracturing blender truck respectively by pipeline with sand tank car, described fracturing blender truck is connected with fracturing car by pipeline, described liquid nitrogen tank car is connected with liquid nitrogen pump vehicle, described fracturing car is connected with high pressure pipe joint respectively by pipeline with described liquid nitrogen pump vehicle, described high pressure pipe joint is extended to shaft bottom along the borehole wall by well head.

2. the equipment of pollution falls in a kind of low pressure and low permeability according to claim 1 saturating reservoir coal bed gas well nitrogen foam pressure break, it is characterized in that, described fracturing blender truck is connected with measuring truck respectively by holding wire with described fracturing car, is monitored the working condition of fracturing blender truck and fracturing car by measuring truck.

3. the equipment of pollution falls in a kind of low pressure and low permeability according to claim 1 saturating reservoir coal bed gas well nitrogen foam pressure break, and it is characterized in that, described tank truck and fracturing car are more than 3, and described liquid nitrogen tank car is more than 2.