Environment-friendly downhole stratum fracturing method

Abstract

The invention discloses an environment-friendly downhole stratum fracturing method, and belongs to the technical field of anti-reflection fracturing of horizontal wells, inclined shafts, vertical wells and the like. The method is achieved through an environment-friendly downhole stratum fracturing device. The environment-friendly downhole stratum fracturing device structurally comprises a well mouth plugging device, a downhole dragging device, well inside packers, a high-pressure hose, a well inside armor cable, a high-strength cable, an operating and control mechanism and a sensor assembly. Through the operating and control mechanism of the device, the downhole dragging device drags the two well inside packers to a set layer position, a set downhole stratum fracturing space is formed, the high-pressure hose is controlled to inject separation liquid, liquid powder, primary powder and the like into a to-be-fractured downhole space according to a formula proportion, the well inside cable is further controlled to carry out electronic ignition, high-energy and high-pressure gas stratum fracturing work is carried out, and multi-repeating or non-repeating stratum fracturing work of different stratum spaces and different stratum conditions is achieved. According to the method, the efficient, economical and environment-friendly stratum fracturing method and device are provided for coalbed methane / shale gas extraction, the fracturing effect is good, a large-range crack system is formed, the permeability of a reservoir stratum is improved, the desorption speed of the reservoir stratum is increased, and the aim of increasing production is achieved. The method and device are worthy of adoption and popularization.

Description

technical field [0001] The environmental-friendly downhole fracturing formation method disclosed by the present invention belongs to the field of anti-permeability fracturing technologies such as horizontal wells, inclined wells, and vertical wells. A new method of downhole complex fracturing formations used. Background technique [0002] Coal bed methane and shale gas are all unconventional natural gas. They are clean, high-quality energy and chemical raw materials that have emerged internationally in the past 10 to 20 years. They have great prospects for commercialization. At present, my country's total coalbed methane resources rank third in the world, and shale gas recoverable reserves rank first in the world, both of which are emerging energy industries that my country focuses on. However, affected by tectonic movements, coalbed methane reservoirs in my country usually have the characteristics of low permeability, low pressure, low gas saturation, and strong heterogene...

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Problems solved by technology

However, the above methods mostly refer to many theoretical viewpoints in oil and gas exploitation to guide the exploitation of coalbed methane / shale gas. The actual fracturing effect is greatly affected by geological conditions, and the fracturing facilities and construction process are complicated, and the consumption of fracturing materials is large. , high cost, poor controllability, certain potential safety hazards, and more or less irreversible damage and pollution to the formation

Among them, hydraulic fracturing causes water-sensitive pollution to the reservoir, the extension direction of the fracture is controlled by the ground stress, and it is difficult to form a multi-fracture system, which has the characteristics of high cost and damage to the reservoir; Equipment and vehicles, as well as a large construction site and a large number of water sources, and it is easy to form irreversible water locks in some formations

High-energy gas fracturing and multi-stage pulse fracturing technologies have many problems such as small fracturing scale, short fracture length, and inability to add filling sand.

while C0 2 / N 2 Foam fracturing technology often contains thickeners such as guar gum, which will be adsorbed on the surface of the reservoir to block the seepage channel; when fracturing coal reservoirs, due to their relatively shallow burial depth and low reservoir temperature, they often cannot be completely broken in time. The high-viscosity fracturing fluid has great resistance to carry sand forward in the reservoir, and the incomplete gel-breaking fluid or the residue after the gel-breaking has a high solid phase content, which is not suitable for low-permeability fracturing fluids. Deep coal seams do a lot of damage

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