There is an increasing focus on the effective methods to develop low-permeability reservoirs, especially for ultra-low permeability reservoirs. It is hard to achieve the expected stimulation effect only on the traditional single fracturing, because of the poor supply ability from the matrix to fracture in low-permeability reservoirs. Volume stimulating to reservoir, achieving short distance from matrix to fracture because of producing fracture network. So the volume fracturing technology proposed for increasing oil or gas production, this technology is suitable for low porosity and low permeability reservoir. The conventional simulation method can't describe the complex fracture network accurately,but this paper established hydraulic fracturing complex fracture model based on the finite element numerical simulation method , making the simulated complex fracture more close to the real description,it can accurately describe the flow state in the reservoir and cracks.It has an important reference value to the low permeability reservoirs.
On the basis of the study of sediment types and dynamic partition zones of heavy minerals assemblage, silt transport tendency in Beidai River coastal sediment are discussed. According to the outcome of analysis of 47 samples of the heavy minerals in Beidai River coastal sediment, it is shown that: (1) there are three heavy minerals epidote, amphibole and iron that were rich in mineral content; (2) light and heavy mineral separation was better, the distribution of which showed a clear saddle shape, and two kinds of high minerals and low showed a pattern of alternate distribution; (3) the general trend of silt transport in Nandai River estuary mouth to the ocean is from southwest to northeast, but on the root of the land to the sea in Beidai River District, the direction of silt transport is from the root to the two wings extending.his template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.
In order to analyze the influence on the motion state of on-off pressure mechanism with flexible link of offset press, pneumatic on-off pressure was as the research object, the three-dimensional model of on-off pressure mechanism was established by using ADAMS, the kinematics simulations of the on-off pressure process was carried out, the curve of the angular velocity, angle acceleration and displacement between rollers of eccentric bushing in both rigid and the rigid-flexible coupled system was got, the significant basis of optimal design for on-off pressure mechanism was provided.
In order to analyze the influence on the printing graphics from the deformation of the printing cylinders and blankets, in this paper, offset printing unit was as the research object, the three-dimensional assembly model of printing cylinders was established by using SolidWorks , the model was imported into finite element software ANSYS, by using ANSYS nonlinear contact calculated functionality, the face-to-face contact of impression surface between plate cylinder and blanket cylinder, blanket cylinder and impression cylinder were established, the stress and strain distribution of blanket were obtained, and the elongation value of circumferential and radial direction of blanket were got, the dot enlargement value was received by simulation analysis.
In this paper, the single and double eccentric combination of pressure regulation device in the offset press was as the object. A closed loop control system of printing pressure and a following pressure regulation device were designed. The rotation angle of eccentric bearing in plate cylinder and the length change of regulating screw were worked out by means of the vector relationship of pressure regulation. The influence on printing quality from the pressure regulation device was analyzed, and it provided a certain basis for the regulation and control of printing pressure.
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