Lateral pressure coefficient is an important parameter in geological engineering, and it influences significantly the damage zone around boreholes. In accordance with the fundamental principles of the Particle Flow Code (PFC), various models were established to investigate the crack propagation patterns and energy evolution rules of coal in …

Jiacheng Wang. 515 Accesses. 4 Citations. Explore all metrics. Article Highlights. The three-dimensional patterns of hydraulic fractures are presented with in situ underground …

Fig. 1 is the principle diagram of TDC in-situ CBM recovery by HWCCSR. The technical keys include: "U"-shaped horizontal-vertical butt well group is deployed in the appropriate position and stratum, horizontal well mainly applied to TDC reservoirs stimulation with cavern completion, and vertical well used for the output of fluid …

Naturally coal beds are composed of matrix and cleat components with relatively independent physical properties (see Fig. 1).Given a single horizontal well production in a coal bed, the CBM (coal bed methane) in the network of cleats would flow into the wellbore under the pressure drop between wellbore and cleat pressures (Fig. 2, …

The aerated UBD pattern of CBM horizontal well is shown in Fig. 24, after the gas is injected into the cave through the tubing in vertical well, it is mixed with the drilling fluid to form a gas–liquid two-phase flow, which is then circulated in annulus and finally returned to surface from the horizontal well, thereby reducing the pressure of ...

Through the technology of direct fracturing coal (Fig. 1 b), that is, multi-stage HFs of horizontal well in coal bed, San Juan basin in the United States and Bowen …

Simulation Study of the Roof Fracture Pattern of a Horizontal Sublevel Caving in a Steeply Inclined Thick Coal Seam Xin Kang,1 Sheng-li Yang,2 Ping Zhan,3 and Liang-hui Li2 1CollegeofCivilEngineering,TongjiUniversity,Shanghai200092,China ... e coal seam inclination angle to be simulated is 55 ...

Among all horizontal borehole patterns simulated, pattern B (tri-lateral pattern), with the longest total borehole length, provided the maximum reduction of gas-in-place within the longwall panel. Its total methane productions were 1.7 × 10 6 m 3 and 4.0 × 10 6 m 3 of methane after 3 and 12 months of methane drainage, respectively.

Given the particular physical property of coal and gas–water migration characteristics in this area, we optimized the well pattern: (i) the U-shaped along-dip horizontal well group in coal seams ...

Understanding flow patterns and their variability is important for optimal design and trouble free dense phase pneumatic conveying of pulverized coal in a horizontal tube. Employing the electrical capacitance tomography (ECT), six flow patterns were identified and utilized for quantitative analysis based on the value and distribution of …

If coal bed thicknesses are the same and L = r, then a horizontal wellbore will be in contact with 64% more rock volume.If L = 2r, then it will be in contact with 128% more volume. π is a mathematical constant and refers to the ratio of a circle's circumference to its diameter, equal to 3.14159.. Multi-branched horizontal coal bed wells (MBHW) …

Given the particular physical property of coal and gas–water migration characteristics in this area, we optimized the well pattern: (i) the U …

These data show that using horizontal borehole pattern B in the Pittsburgh coalbed reduces the average face emission rates by as much as 10.3 m 3 /min (364 cfm) …

The Longde Coal Mine of Huadian Corporation mainly mines a 2 −2 coal seam, which is a near-horizontal coal seam with an average thickness of 3.5 m, an average depth of 200 m, and an inclination of 1~2°. The coal seam has a simple structure and contains parting bands in local areas. It is a stable recoverable coal seam.

Coal seam gas (CSG), also known as coalbed methane (CBM), is an important source of gas supply to the liquefied natural gas (LNG) exporting facilities in eastern Australia and to the Australian …

For dealing with the deformation of coal pillars, the horizontal strain (({varepsilon }_{x ... Study on the air leakage pattern of coal body in roadway. J Xi'an Jiaotong Univ 03:239–243. Google Scholar Zongxiang Li, Sun Guangyi Sun, Jibo Wang (2001) Numerical simulation of air leakage and oxygen consumption process in coal …

Horizontal wells, such as multi-lateral and multi-branched horizontal wells (MBHWs) have been effectively used in the development of coalbed methane (CBM) …

tribution pattern and continued to expand forward in the horizontal direction, which formed a"wave"-type periodic motion. Then, a new"three-in-one" gas control mode was proposed with the evolution anddistribution law of mining fractures. Zhou et al. [45, 46] obtained the deformation law of the coal seam by combining physical simulation and

Fan cut Drilling pattern. Burn cut. Coromant cut. Ring cut Drilling pattern. 1. Pyramid cut or Cone cut. इस पोस्ट में देखेंगे drilling pattern in underground coal mines और all 7 types of blasting design patterns जैसे wedge cut drilling pattern, pyramid cut drilling pattern, burn cut drilling pattern ...

Concepts 2.1C and 2.1D demonstrate how the outcrop pattern changes in maps for two oppositely dipping beds. Three maps will be discussed in this chapter: Map 2.1 (horizontal beds), Map 2.2 (inclined beds), and Map 2.3 (three point construction of strike lines). Download : Download full-size image Concept 2.1C. (A) Exposure of an inclined …

Sociology questions and answers. geometry (using structure contours and structure section) 4. The attached figure shows the outcrop pattern of a fault plane (F) displacing a coal seam. Slickenlines on the fault indicate pure dip slip motion. - A) Construct a cross-section along line X-Y without vertical exaggeration (to do this successfully ...

The subsidence pattern of the coal seam within a range of approximately 146 m above the remaining coal pillar is convex and in a non-sufficient subsidence state, which is close to the ...

RU2293833C1 - Method for making horizontal draining system ... FIELD: technology for extraction of mineral resources from underground formations, in particular, method and system for providing access to underground formations from earth surface, and method for producing gas from coal bed, which substantially reduce or abolish disadvantages and …

The floor elevation of the coal seam varied between 931.6 and 944.0 m. It extends in the 65° direction, dips at 255°, and has an inclination of 1–3°, classifying it as a nearly horizontal coal seam. The main roof predominantly consists of sandy mudstone and medium-grained sandstone, with thicknesses ranging from 9.15 to 24.85 m.

Pneumatic conveying experiments of pulverized coal were carried out in three experimental systems which were vertical conveying of 20 mm pipe diameter, horizontal conveying of 20 mm and 50 mm pipe diameter. The ECT was employed to research flow patterns in vertical and horizontal pipes and the empirical formulas were …

For example, for a coal mine at 300 ft (90 m) of cover and a modulus of 3 x 106 psi (4.3 GPa), the total predicted horizontal stress is 1693 psi (11.9 MPa). The excess stress accounts for 1,432 psi (9.9 MPa), and the depth effect contributes just 261 psi (1.8 MPa) to …

According to the theory of the trapezoidal broken model established by Xu et al. [15] and the V-shaped conceptual model of fracture evolution patterns in the overlying strata during horizontal ...

The dynamic evolution of mining-induced fractures in overlying strata caused by mining has non-ignorable effects on engineering safety and water loss from an overlying aquifer. To clarify the evolutionary patterns of fractures due to the first and periodic weighting induced by coal mining, W-shaped fracture arch models are developed to …

For vertical well, the regular well pattern is usually adopted in conventional reservoir with relatively homogeneous formation, and the basic well pattern unit is a rectangle (square) or equilateral triangle. ... and fracturing operations on an assembly line. In addition, the coal/water/oil resources overlay requires a larger number of extended ...

Surface drilled horizontal coalbed methane (CBM) wells have become the predominant method for degasification in advance of mining, and gas recovery in areas …