Study and application of a new gas pressure inversion model in coal seam while drilling based on directional drilling technology

Directional drilling technology is an important and very promising trenchless pipeline crossing technology. On the basis of the related literature research at home and abroad and our pipeline construction site investigation, focuses on several common soil properties are introduced, and then the formation adaptability of directional drilling is analyzed. The drilling selection methods are made when drilling in the specific geological conditions, and the possible risks of the construction process have been classified in the directional drilling.

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Permeability Enhancement Properties of High-Pressure Abrasive Water Jet Flushing and Its Application in a Soft Coal Seam

Frontiers in Energy Research ◽

10.3389/fenrg.2021.679623 ◽

2021 ◽

Vol 9 ◽

Author(s):

Xinzhe Zhang ◽

Piotr Wiśniewski ◽

Sławomir Dykas ◽

Guojie Zhang

Keyword(s):

High Pressure ◽

Coal Seam ◽

Water Jet ◽

Gas Pressure ◽

Theory And Practice ◽

Abrasive Water Jet ◽

Gas Drainage ◽

Permeability Enhancement ◽

Soft Coal ◽

Soft Coal Seam

High-pressure abrasive water jet flushing (HPAWJF) is an effective method used to improve coal seam permeability. In this study, based on the theories of gas flow and coal deformation, a coupled gas-rock model is established to investigate realistic failure processes by introducing equations for the evolution of mesoscopic element damage along with coal mass deformation. Numerical simulation of the failure and pressure relief processes is carried out under different coal seam permeability and flushing length conditions. Distributions of the seepage and gas pressure fields of the realistic failure process are analyzed. The effects of flushing permeability enhancement in a soft coal seam on the gas drainage from boreholes are revealed by conducting a field experiment. Conclusions can be extracted that the gas pressure of the slotted soft coal seam is reduced and that the gas drainage volume is three times higher than that of a conventional borehole. Field tests demonstrate that the gas drainage effect of the soft coal seam is significantly improved and that tunneling speed is nearly doubled. The results obtained from this study can provide guidance to gas drainage in soft coal seams regarding the theory and practice application of the HPAWJF method.

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Study on the Interaction between Low-Viscosity High-Permeability Pregrouting Sealing Material and Coal and Its Application

Advances in Polymer Technology ◽

10.1155/2020/1217285 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Yujia Chen ◽

Ao Li ◽

Dingding Yang ◽

Tianyu Liu ◽

Xiaowei Li ◽

...

Keyword(s):

Coal Seam ◽

Bending Strength ◽

Formation Rate ◽

Field Application ◽

Gas Pressure ◽

Polymer Materials ◽

Target System ◽

High Permeability ◽

Low Viscosity ◽

New Material

In order to ensure the intactness of pressure-measuring boreholes and the accuracy of gas pressure determination, pregrouting treatment with polymer materials is frequently applied to bedding drilling in coal mines. However, the existing polyurethane materials are of high viscosity, low permeability, and poor safety, bringing great difficulties to their field promotion and application. In view of this problem, after optimization and experiments, polylactide polyol/polyether polyol 4110/isocyanate was determined as the target system. Bio-based benzoxazine (Boz-F), red phosphorus, and melamine with a mass ratio of 2 : 1 : 2 were used as the flame retardant, which then underwent mechanical modification by hollow glass bubbles. Finally, the pregrouting material with low viscosity and high permeability was compounded, and its interaction with coal was experimentally studied. The results show that compared with traditional polyurethane, the new material increases the effective consolidation distance in the coal seam by 40% on average. Its permeation radius is also larger than the calculated radius of the plastic softening zone of a borehole. In addition, the strengths of coal-new material consolidated products with different ratios fully surpass those of coal-polyurethane material consolidated products. The enhancement of compressive strength and bending strength is up to 153% and 161%, respectively. The field application indicates that after pregrouting treatment of boreholes in the coal seam with the new material, the borehole formation rate reaches 100%. Therefore, the new material is safe and practical for gas pressure measurement through bedding drilling on site.

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Investigation of the Flow Properties of CBM Based on Stochastic Fracture Network Modeling

Materials ◽

10.3390/ma12152387 ◽

2019 ◽

Vol 12 (15) ◽

pp. 2387 ◽

Cited By ~ 8

Author(s):

Bo Zhang ◽

Yong Li ◽

Nicholas Fantuzzi ◽

Yuan Zhao ◽

Yan-Bao Liu ◽

...

Keyword(s):

Coal Seam ◽

Gas Flow ◽

Distribution Patterns ◽

Element Model ◽

Fracture Network ◽

Gas Pressure ◽

Computational Domain ◽

Fracture Density ◽

Flow Properties ◽

Fracture Network Modeling

Coal contains a large number of fractures, whose characteristics are difficult to describe in detail, while their spatial distribution patterns may follow some macroscopic statistical laws. In this paper, several fracture geometric parameters (FGPs) were used to describe a fracture, and the coal seam was represented by a two-dimensional stochastic fracture network (SFN) which was generated and processed through a series of methods in MATLAB. Then, the processed SFN image was able to be imported into COMSOL Multiphysics and converted to a computational domain through the image function. In this way, the influences of different FGPs and their distribution patterns on the permeability of the coal seam were studied, and a finite element model to investigate gas flow properties in the coal seam was carried out. The results show that the permeability of the coal seam increased with the rising of fracture density, length, aperture, and with the decrease of the angle between the fracture orientation and the gas pressure gradient. It has also been found that large-sized fractures have a more significant contribution to coal reservoir permeability. Additionally, a numerical simulation of CBM extraction was carried out to show the potential of the proposed approach in the application of tackling practical engineering problems. According to the results, not only the connectivity of fractures but also variations of gas pressure and velocity can be displayed explicitly, which is consistent well with the actual situation.

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Trenchless Pipe-Paving in Complex Hard Stratum by Directional Drilling Technology

Geological Engineering: Proceedings of the 1 ◽

10.1115/1.802922.paper26 ◽

2010 ◽

pp. 1-8

Author(s):

Wen Guojun ◽

Wu Xiaoming ◽

Chen Han

Keyword(s):

Directional Drilling ◽

Drilling Technology

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A method of rapid determination of gas pressure in a coal seam based on the advantages of gas spherical flow field

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2017.05.021 ◽

2017 ◽

Vol 45 ◽

pp. 502-510 ◽

Cited By ~ 20

Author(s):

Chaojie Wang ◽

Shengqiang Yang ◽

Chenglin Jiang ◽

Dingding Yang ◽

Chaojie Zhang ◽

...

Keyword(s):

Flow Field ◽

Coal Seam ◽

Rapid Determination ◽

Gas Pressure

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Evaluation of utilizing horizontal directional drilling technology for ground source heat pumps

Geothermics ◽

10.1016/j.geothermics.2019.101769 ◽

2020 ◽

Vol 85 ◽

pp. 101769 ◽

Cited By ~ 5

Author(s):

Saeid Mohammadzadeh Bina ◽

Hikari Fujii ◽

Shunsuke Tsuya ◽

Hiroyuki Kosukegawa ◽

Shigemi Naganawa ◽

...

Keyword(s):

Heat Pumps ◽

Directional Drilling ◽

Horizontal Directional Drilling ◽

Ground Source Heat Pumps ◽

Ground Source ◽

Drilling Technology

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Directional drilling oil and gas wells

10.12737/textbook_5a1521453b20d7.29773613 ◽

2017 ◽

Author(s):

Вячеслав Нескоромных ◽

Vyacheslav Neskoromnykh

Keyword(s):

Oil And Gas ◽

Directional Drilling ◽

Gas Wells ◽

Field Of Study ◽

Business Training ◽

Oil And Gas Wells ◽

Drilling Technology

The basic issues of the theory and technique of directional drilling technology applied to drilling for oil and gas. Provides information on the causes and patterns of curvature of the wells, tools, and technologies for drilling wells along set trajectories, technologies and technical means of the curvature of the wells, the drilling of multilateral wells. Examples of calculations and the basic terminology. For students enrolled in field of study 21.03.01 "Oil and gas business", training 21.03.01.01 "Drilling oil and gas wells" (fgos VPO – 2015); specialty 21.05.06 "Oil and gas equipment and technologies", specialization "Technology of drilling oil and gas wells" (fgos VPO – 2014).

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