CN205477511U - Prevent releasing hydraulic fracturing hole sealing device - Google Patents

Abstract

The utility model discloses a mining prevent releasing hydraulic fracturing hole sealing device, the hole sealing capsule, check valve, the end cap that set gradually on the fracturing pipe, the fracturing pipe is big from the middle part diameter, and the bulging tripe shape hole sealing capsule center that the both ends diameter is little is passed, and the fracturing pipe is glued intracapsular part at the hole sealing and is provided with the apopore. This hole sealing device can effectively prevent the hydraulic fracturing in -process and release drilling because injection pressure is too big with the hole sealing capsule, causes the drawback of fracturing failure, compare with conventional water conservancy hole sealing capsule, but this hole sealing device and big, the sealed effectual reuse of drilling area of contact, simple structure, safe and reliable.

Description

An anti-extrusion hydraulic fracturing sealing device

technical field

The utility model relates to the technical field of downhole fracturing drilling and sealing, in particular to a method of using a sealing capsule to expand the "bulge" section and insert it into the drilling reaming section to increase the adhesion between the capsule and the drilling and improve the sealing effect. 1. The technical field of preventing capsules from being pushed out of drilling holes.

Background technique

As the main means to solve the coal mine gas problem, pre-mining coal seam gas extraction has always been valued by coal mining technicians. According to statistics, more than 95% of coal seams mined by high-gas mines and outburst mines in my country belong to low-permeability coal seams, which often causes the embarrassment of "gas can't be pumped out" in gas drainage work. Since the Shenyang Research Institute first applied hydraulic fracturing technology in the field of enhanced gas drainage in low-permeability soft coal seams in the 1960s, the technical theory research and equipment research and development of hydraulic fracturing have made great progress.

At present, the sealing technology of hydraulic fracturing drilling mainly includes three methods: cement mortar or chemical slurry sealing and hole sealing with hole sealing device. The problem of the cement mortar sealing method is that cracks will appear after the cement is consolidated, forming air leakage channels and affecting the sealing effect; the sealing strength of the chemical slurry sealing method such as polyurethane is limited, the expansion rate is not easy to control, and the expansion and consolidation of the slurry Afterwards, it is easy to separate from the borehole wall due to shrinkage, resulting in air leakage. These two sealing methods are cumbersome and cannot be reused, and are mainly suitable for permanent sealing sites. Hole sealing can be divided into friction type and hydraulic expansion type according to its sealing principle. Field practice shows that the friction sealer is too bulky and has a small expansion coefficient, so the sealing effect is not ideal. Therefore, the hydraulic fracturing hole sealer in the coal mine generally adopts the reusable hydraulic expansion type hole sealing method. After the general hole sealer is set, the middle part is a cylinder. Due to the limitation of the length, the contact area between the capsule and the borehole is limited. At the time of thrust, the peristalsis of the fracturing string may push the sealing capsule out of the borehole when the fracturing pump supplies fluid, and the high-pressure water in the capsule poses a greater threat to the safety of the surrounding construction personnel. It is very necessary to use a hole sealer to prevent the sealing capsule from being pushed out of the drill hole due to the peristalsis of the pipe string.

Contents of the invention

Aiming at the deficiencies in the prior art, the utility model provides an anti-extrusion hydraulic fracturing sealing device. By changing the existing cylindrical capsule into a bulging shape, the adhesion between the capsule and the drill hole is increased, and the pressure is prevented. The capsule is pushed out of the drill hole during the cracking process.

The technical solution of the present invention is: an anti-extrusion hydraulic fracturing sealing device, comprising a sealing capsule, a one-way valve, and a plug arranged on the fracturing tube in sequence; the fracturing tube passes through the center of the sealing capsule and The part inside the hole capsule is provided with a water outlet hole, the end of the fracturing pipe is provided with a plug, and a one-way valve is provided between the capsule and the plug.

The hole-sealing capsule is bulging and divided into three sections according to the length. The diameter of the middle part is large, and the diameter of both ends is small. The two ends of the capsule are fixed on the fracturing pipe by high-pressure pipe hoops.

The diameter of the middle part where the diameter of the sealing capsule increases is smaller than the diameter of the drilled hole.

The length of the middle portion where the diameter of the sealing capsule increases is shorter than the length of the drilling and reaming section.

The beneficial effect of the utility model is: compared with the traditional hydraulic hole sealer, the sealing capsule adopts a bulging design, and when the sealing capsule expands, the bulging "belly" of the capsule is just embedded in the drilled hole In the cavity of the fracturing, when the fracturing starts, the capsule is subjected to the thrust of the high-pressure water in the fracturing section on the capsule outward along the axial direction of the borehole. The thrust force of the drilling cavity to the capsule into the drilling hole is greatly enhanced, the stability of the capsule is greatly enhanced, and the danger of the capsule being pushed out of the drilling hole is effectively prevented. The device has simple structure, strong operability and is convenient for technology popularization.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the device before fracturing of the utility model.

Fig. 2 is a schematic diagram of the structure of the utility model after fracturing.

detailed description

Below in conjunction with shown in accompanying drawing 1, 2, a kind of anti-extrusion hydraulic fracturing sealing device is described further, in this example, along the coal seam drilling length 80m, aperture 94mm. In order to realize the safe and effective sealing of the hydraulic fracturing drilling, the utility model adopts the following device and sealing method.

As shown in Figure 1, an anti-extrusion hydraulic fracturing sealing device includes a sealing capsule (3), a one-way valve (5), and a plug (6), etc., which are sequentially arranged on the fracturing pipe (1); The split tube (1) passes through the center of the sealing capsule (3) and is provided with a water outlet hole (4) inside the sealing capsule (3), and a plug (6) is provided at the end of the fracturing tube (1), A one-way valve (5) is arranged between the capsule (3) and the plug (6).

In particular, the hole-sealing capsule (3) is bulging and is divided into three sections according to the length. The diameter of the middle part is large and the diameter of both ends is small. (1) up.

In particular, the diameter of the middle part where the diameter of the sealing capsule (3) increases is smaller than the diameter of the drilled hole.

When sealing holes, the hole sealing device is used in conjunction with other equipment, and the hole sealing method includes the following steps:

(1) Pre-construction design: According to the lithology of the coal seam as the surrounding rock of the drilling and the properties of the drilling along the coal seam, the length of the sealing section of the drilling hole is determined to be 1.5m, and the sealing depth is 5m. The sealing capsule is designed according to the length of the sealing section (3) The total length is 1.5m, which is divided into 3 sections on average. The length of a single section is 0.5m, the diameter of the middle part is 80mm, and the diameter of both ends is 60mm.

(2) Reaming: use a special reaming machine to expand a section of drilling cavity with a length of 0.8m and a diameter of 120mm at a distance of 3.7m from the drilling hole;

(3) Lowering the hole sealing device: put the anti-extrusion hydraulic fracturing sealing device into the borehole, and record the distance between the outer side of the "belly" section and the hole opening of the sealing capsule (3), when the distance reaches 3.8m Stopping the lowering of the device;

(4) Connect the fracturing pump to the fracturing pipe (1), and after the pressure test checks that all sections are connected, turn on the fracturing pump, and the fracturing fluid enters the sealing capsule (3) through the water outlet hole on the fracturing pipe for use. The capsule (3) expands, and the middle part of the capsule (3) expands and embeds in the cavity at the reaming part of the drilled hole and is in close contact with it. The two ends of the capsule (3) are in close contact with the unreamed part of the drilled hole to realize the sealing of the drilled hole ;As the injection pressure continues to rise, when the opening pressure of the one-way valve (5) is reached, the fracturing fluid flows from the one-way valve (5) into the fracturing target layer in the borehole;

(5) Turn off the fracturing pump after the fracturing is completed, and pull the fracturing string out of the borehole after the sealing capsule (3) is unsealed.

In particular, the length of the middle portion where the diameter of the sealing capsule (3) increases is shorter than the length of the drilling and reaming section.

Claims (4)

1. An anti-protrusion hydraulic fracturing sealing device, characterized in that: the fracturing tube is successively provided with a sealing capsule, a one-way valve, a plug; the fracturing tube passes through the center of the sealing capsule The inner part is provided with a water outlet hole, the end of the fracturing pipe is provided with a plug, and a one-way valve is provided between the capsule and the plug. 2. An anti-extrusion hydraulic fracturing sealing device according to claim 1, characterized in that: the sealing capsule is bulging, divided into three sections according to the length, the middle part has a large diameter, and the two ends The diameter is small, and both ends of the capsule are fixed on the fracturing pipe through high-pressure pipe hoops. 3. The anti-extrusion hydraulic fracturing sealing device according to claim 2, characterized in that: the diameter of the middle portion of the sealing capsule where the diameter increases is smaller than the diameter of the borehole. 4 . The anti-extrusion hydraulic fracturing sealing device according to claim 3 , characterized in that: the length of the middle part where the diameter of the sealing capsule increases is shorter than the length of the drilling and reaming section. 5 .