Some hydrocarbon reservoirs are trapped beneath salt bodies, where seismic imaging is greatly challenged due to poor illumination. Multiple reflections have different propagation wave paths from primary and thus can be used complement the illuminations not acquired. Consequently, migration of multiples sometimes provide better subsalt images compared conventional which uses only. In this paper, we propose modify reverse time so that as constructive reflection energy for imaging. This new...

The eastern margin of the Tibetan Plateau is an area with youngest uplift, strongest deformation, and frequent occurrence large earthquakes. Seismic velocity can constrain lithosphere's rheological strength crustal flow distribution, allowing deformation to be explored for crust upper mantle. However, seismic related rock composition reflects rock's elastic behavior. As a direct anelastic observation deep temperature strength, attenuation decrease multiplicity geodynamic interpretation. We...

Prestack reverse time migration (RTM) is usually regarded as an accurate imaging tool and has been widely used in exploration. Conventional RTM only uses primaries treats free-surface related multiples noise; however, can sometimes provide extra illumination of the subsurface, this information could be procedures. There are many methods using multiples, but most approaches need to predict which consuming prone error. We discovered a new approach that simultaneously. Compared with use...

Free-surface-related multiples are usually regarded as noise in conventional seismic processing. However, they can provide extra illumination of the subsurface and thus have been used migration procedures, e.g., one- two-way wave-equation migrations. The disadvantage is artifacts generated by crosscorrelation different events, primaries second-order free-surface-related multiples, so effective elimination crucial for multiples. angle domain common image gather (ADCIG) a suitable testing...

Identifying and locating microseismic events are critical problems in hydraulic fracturing monitoring for unconventional resources exploration. In contrast to active seismic data, data usually recorded with unknown source excitation time location. this study, we introduce deconvolution migration by combining interferometry interferometric cross-correlation (CCM). This method avoids the need enhances both spatial resolution robustness eliminating square term of wavelets from CCM. The proposed...

In the implementation of migration multiples, reverse time (RTM) is superior to other algorithms because it can handle steeply dipping structures and offer high-resolution images complex subsurface. However, RTM results using two-way wave equation contain high-amplitude, low-frequency noise false generated by improper paths in velocity model with sharp interfaces or strong gradients. To improve imaging quality we separate upgoing downgoing waves propagation source receiver wavefields. A...

A 3‐D tomographic inversion approach based on a surface‐consistent model for static corrections is presented in this paper. Direct, reflected, and refracted waves are used simultaneously to update the near‐surface model. We analyze characteristics of first‐break traveltime complicated low‐velocity layers. To improve accuracy velocity model, various times from direct, considered inversion. fractal algorithm which overcomes error caused by wavelet shape differences applied pick first breaks....

Least-squares migration (LSM) is a linearized inversion technique for subsurface reflectivity estimation. Compared to conventional algorithms, it can improve spatial resolution significantly with few iterative calculations. There are three key steps in LSM, (1) calculate data residuals between observed and demigrated using the inverted model; (2) migrate form gradient (3) update model optimization methods. In order obtain an accurate high-resolution result, good estimation of inverse Hessian...

Locating microseismic sources is critical to monitoring the hydraulic fractures that occur during fluid extraction/injection in unconventional oil/gas exploration, geothermal operations, and CO 2 sequestration. Waveform-based seismic location methods can reliably automatically image weak source locations without phase picking. Among them, crosscorrelation migration (CCM) method avoid excitation time scanning by generating virtual gathers. We have adopted a CCM based on hybrid imaging...

The separation of upgoing and downgoing wavefields is an important technique in the processing vertical seismic profiling data ocean bottom cable data. It also used reverse time migration (RTM) based on two-way wave equation to suppress low-frequency, high-amplitude noises false images. Therefore, we model directly wavefield propagation. There are several methods obtain separated wavefields. using Fourier transform require storage wavefields, which not practical due extremely high disk-space...

To eliminate crosstalk within the imaging results of elastic reverse time migration (ERTM), we can separate coupled P- and S-waves from forward source wavefield backpropagated receiver wavefield. The S-wave decoupling method retains original phase, amplitude, physical meaning in separated wavefields. Thus, it is a vital separation ERTM. However, because these decomposed wavefields are vectors, could consider how to retrieve scalar images that reveal real reflectivity subsurface. For this...

The advantages of simultaneous sources acquisition are weakened by blended noise. Many conventional filtering methods ineffective due to the existence coherent noise in common shot gather (CSG). However, interference appears be incoherent a midpoint (CMP) domain. In light this characteristic, we propose high-resolution radon transform based deblending approach. There four steps for implementation: (1) original data from CSG domain CMP domain; (2) apply obtain spectrum; (3) filter spectrum...

Microseismic data usually have a low signal-to-noise ratio, necessitating the application of an effective denoising method. Most conventional methods treat each component multicomponent separately, e.g., with sparse representation. However, microseismic are often acquired 3C receiver, especially in borehole monitoring cases. Independent ignores relative amplitudes and vector relationships between different components. We developed new simultaneous method for based on joint The three...

Abstract The shortest ray path method based on graphic structure overcomes the drawbacks and limitations of traditional ray‐tracing methods, but computation time accuracy results need to be improved. This paper introduces Bresenham line algorithm into traveltime calculating nodes improve results. To speed up computation, it uses QuickSort Insertion Sort instead usually used HeapSort algorithm. We take advantage node configuration presented in this introduce velocity interface, accordingly...

ABSTRACT The conventional reverse time migration of ground‐penetrating radar data is implemented with the two‐way wave equation. cross‐correlation result contains low‐frequency noise and false images caused by improper paths. To eliminate improve quality image, we propose to separate left‐up‐going, left‐down‐going, right‐up‐going right‐down‐going wavefield components in forward‐ backward‐propagated wavefields based on Hilbert transform. By applying full decomposition transform, obtain...

We have determined the three-dimensional P-wave velocity structure beneath north-south tectonic belt between Tibet and Eastern China by simulta- neously inverting local, regional, teleseismic data. Our data set is composed of 45,028 arrival times from 602 local regional earthquakes 985 travel 102 events. With LSQR (sparse linear equations least squares) algorithm, perturbations were estimated simul- taneous inversion hypocenters medium parameters surface to a depth 200 km. tested stability...

Surface-related multiple elimination (SRME) typically consists of two steps: The first step is prediction and the second subtraction. In subtraction, it important to effectively attenuate events preserve primary events. When multiples cross with or overlap on primaries, least-square subtraction usually cannot subtract may also damage primaries. always accurately often damages To remedy this problem, we propose statistically estimate inverse source wavelet, correct for errors in then use...

During the hydraulic fracturing procedure in shale-gas exploitation, poroelastic properties of shale formation can be altered significantly. However, it is difficult to evaluate these variations using microseismic field data. In this study, we conduct a hydro-fracturing experiment Longmaxi shale, which major for production China, simulate water injection and rock procedure. The variation velocity attenuation primary/secondary (P/S) ultrasonic waves was investigated throughout entire...