Publications by authors named "Yuanda Su"

Many oil and gas fields, especially non-conventional shale and compacted sand reservoirs, have formation anisotropy. The acoustic anisotropy measurement of cores in these reservoirs can guide drilling, well logging, and exploitation. However, almost all core holders are designed for cylinder cores, which are not suitable for all-directional measurements.

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Well logging is performed in oil and gas exploration wells to obtain the physical characteristics of underground formations. Thereafter, these wells are cased. Through-casing logging is important in mature fields and for wells that are cased without logging due to borehole stability issues.

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To obtain qualified logging while drilling (LWD) data, a new acoustic LWD tool was designed. Its overall design is introduced here, including the physical construction, electronic structure, and operation flowchart. Thereafter, core technologies adopted in this tool are presented, such as dominant exciting wave bands of dipole source, a sine wave pulse excitation circuit, broadband impedance matching, and an intellectualized active reception transducer.

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An anisotropic physical model is constructed to evaluate the anisotropy measurement. The model consists of a series of equally spaced thin limestone slab sheets cemented with concrete, resulting in a transversely isotropic medium. For the anisotropy measurement evaluation, the borehole model is tested by a standard multipole acoustic tool.

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The development of acoustic source technology has been an important task for acoustic logging while drilling (LWD) and various source designs have been implemented. Using a multipole wave expansion theory, this study demonstrates that a LWD acoustic source can be represented as a combination of monopole, dipole, and quadrupole constituents and characterized by the contribution of each constituent. The theoretical analysis is experimentally demonstrated with a cylindrical pipe simulating the LWD collar.

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A hybrid method based on the finite-difference method and equivalence principle to simulate elastic wave scattering of three-dimensional objects is proposed. In this method, the near fields are first calculated in a rectangular volume containing the object by the finite-difference method. Then the displacements and tractions on a virtual surface are transformed to the far field by the application of the equivalence principle in elastodynamics.

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The seismoelectric interface electromagnetic characteristics have been studied for the finite offset Vertical Seismoelectric Profiling (VSEP) configuration. The approach consists of theoretical modeling and laboratory verification. The results show that the wave variation characteristics along the finite offset measurement line are markedly different from those along the zero-offset line.

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The interaction of a fluid-filled borehole with incident elastic waves is an important topic for downhole acoustic measurements. By analyzing the wave phenomena of this problem, one can simulate the detection of a borehole target using a source-receiver system in a remote borehole. The analysis result shows that the wave signals from the target borehole are of sufficient amplitude even though the borehole size is small compared to wavelength.

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The stopband of pipe extensional waves is an interesting natural phenomenon. This study demonstrates an important extension of this phenomenon. That is, the stopband can be effectively broadened by transmitting the waves across the joint of pipes of different thickness.

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The aim of this article is to report the application of expanding retroauricular skin fascia flap, and autogenous costal cartilage for congenital microtia reconstruction. Microtia reconstruction was generally completed in 3 surgical stages. In the first surgical stage, a 50 or 80 mL kidney-shaped tissue expander was inserted subcutaneously in the retroauricular mastoid region.

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