Separating and imaging diffractions in dip domain on the basis of slope analysis

Fracture-cave reservoirs in carbonate rocks are characterized by a large difference in fracture and cavity size,and a sharp variation in lithology and velocity,thereby resulting in complex diffraction responses.Some small-scale fractures and caves cause weak diffraction energy and would be obscured by the continuous reflection layer in the imaging section,thereby making them difficult to identify.This paper develops a diffraction wave imaging method in the dip domain,which can improve the resolution of small-scale diffractors in the imaging section.Common imaging gathers(CIGs)in the dip domain are extracted by Gaussian beam migration.In accordance with the geometric differences of the diffraction being quasilinear and the reflection being quasiparabolic in the dip-domain CIGs,we use slope analysis technique to filter waves and use Hanning window function to improve the diffraction wave separation level.The diffraction dip-domain CIGs are stacked horizontally to obtain diffraction imaging results.Wavefield separation analysis and numerical modeling results show that the slope analysis method,together with Hanning window filtering,can better suppress noise to obtain the diffraction dip-domain CIGs,thereby improving the clarity of the diffractors in the diffraction imaging section.

The gravity and isostatic Moho in North China Craton and their implications to seismicity

The Bouguer gravity is the combination of field sources in different depths. Based on the multi-scale analysis of the Bouguer gravity,we can get the gravity anomaly caused by the Moho undulation. This study presents the various orders of approximation of gravity anomaly in North China Craton（NCC）,the possible source depths with radial logarithmic power spectrum,and the relationship between the deep structure and gravity anomaly. Furthermore,we discuss the isostatic compensation about the Moho depth from gravity and deep seismic sounding profiles（DSS）. The results show that：（1） the fourth approximation could have resulted from the Moho undulation,（2） in contrast to the isostatic Moho,the inverted gravity Moho and the DSS Moho show that most of NCC has been isostatically compensated,and（3） the isostatic compensation rate has some close relation to the seismicity.

The Significance of Wettability in Tight Oil Exploration and Development

With the increasing of energy demand and conventional oil and gas resources depletion, unconventional oil and gas resources are getting more and more attention, and have become a major contributor to the global oil and gas production growth over the past five years （Zou et al., 2012; Jia et al., 2014）.

Study of Organic Heterogeneity Evaluation Methods

The organic heterogeneity evaluation technology has been very important in the unconventional oil and gas exploration. In the different basin , the accurate description of the shale＇s organic carbon content in the vertical and horizontal distribution characteristics, having a very important influence on the evaluation of the hydrocarbon source rock, the calculation of the hydrocarbon generation and expulsion efficiency, even the prediction of hydrocarbon distribution and so on.

The Research Progress on the Occurrence Mechanism of Detained Hydrocarbon

Unconventional oil and gas resources are closely to the retaining ability of hydrocarbon of source rock. The detained hydrocarbon can be divided to two parties： organic retaining ability including the swelling and adsorption function of kerogen and retaining ability of organic pore, and inorganic retaining ability including adsorption of detrital minerals and retaining ability of inorganic pore.

The Influence of Pore Throat Radius on its Internal Oil and Water Wettability

With the rising of energy demand and the dwindling of conventional oil and gas resources, the unconventional oil and gas resources are getting more and more attention, and has become the main contribution of global oil and gas production growth over the past five years.