【摘 要】
：
Three large-scale episodes of volcanic activity occurred during the Tertiary in the Xihu Depression,located in the East China Sea.Intermediate-felsic magmas intruded along faults and the associated hydrothermal fluids resulted in the hydrothermal alterati
【机 构】
：
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Techno
论文部分内容阅读
Three large-scale episodes of volcanic activity occurred during the Tertiary in the Xihu Depression,located in the East China Sea.Intermediate-felsic magmas intruded along faults and the associated hydrothermal fluids resulted in the hydrothermal alteration of the clastic country rock.To better describe reservoir characteristics,reservoir samples were subjected to the following investigations:thin section examination,scanning electron microscope-energy dispersive spectrometer analysis (SEM-EDS),fluid inclusion homogenization temperature tests,vitrinite reflectance measurements,and X-ray diffraction.The results of this study provide evidence of the following hydrothermal alteration phenomena:brittle fracturing,clastic particle alteration,precipitation of unique hydrothermal minerals (celestite,zircon,apatite,barite,and cerous phosphate).The presence of abnormally high temperatures is indicated by fluid inclusion analysis,the precipitation of high-temperature authigenic minerals such as quartz,i11ite alteration,and anomalous vitrinite reflectance.Two aspects related to hydrothermal effects on reservoir properties have been investigated in this study:(1) Deep magmatic hydrothermal fluids carry large amounts of dissolved carbon dioxide and sulfur dioxide gas.These fluids percolate into the country rocks along fault zones,resulting in dissolution within the sandstone reservoirs and the development of significant secondary porosity.(2) Magma intrusions increase the temperature of the surrounding rocks and accelerate the thermal evolution of hydrocarbon source rocks.This results in the release of large amounts of organic acids and carbon dioxide,leading the dissolution of the aluminosilicate minerals and volcanic fragments in the reservoirs,and the generation of significant secondary porosity.
其他文献
The brittleness prediction of shale formations is of interest to researchers nowadays.Conventional methods of brittleness prediction are usually based on isotropic models while shale is anisotropic.In order to obtain a better prediction of shale brittlene
Envelope inversion (EI) is an efficient tool to mitigate the nonlinearity of conventional full waveform inversion (FWI) by utilizing the ultralow-frequency component in the seismic data.However,the performance of envelope inversion depends on the frequenc
The reconstruction of thermal history is an important component of basin evolution and hydrocarbon exploration.Based on vitrinite reflectance data,we integrate the paleo-temperature gradient and paleo-heat flow methods to reconstruct the thermal history o
Quantitative inversion of fracture weakness plays an important role in fracture prediction.Considering reservoirs with a set of vertical fractures as horizontal transversely isotropic media,the logarithmic normalized azimuthal elastic impedance (EI) is re
The overseas oil and gas investment evaluation is one of the core tasks in overseas investment of oil and gas companies,among which risk evaluation and benefit evaluation are the most important.This paper sets forth transmission paths of risk factors to t
An experimental apparatus including a dipleg and a trickle valve was established to simulate the operation of a suspended dipleg-trickle valve system of cyclone used in fluid catalytic cracking (FCC) unit.The flow regimes in the dipleg and the discharge m
Assessment of reservoir and fracture parameters is necessary to optimize oil production,especially in heterogeneous reservoirs.Core and image logs are regarded as two of the best methods for this aim.However,due to core limitations,using image log is cons
Yield stress,as the key parameter to characterize the network strength of waxy oil,is important to the petroleum pipeline safety.Reducing the yield stress of waxy oil is of great significance for flow assurance.In this study,the effect of alternating magn
Although coal swelling/shrinking during coal seam gas extraction has been studied for decades,its impacts on the evolution of permeability are still not well understood.This has long been recognized,but no satisfactory solutions have been found.In previou
Compared with hyperbolic velocity estimation methods,nonhyperbolic methods (such as shifted hyperbola) are better choices for large offsets or vertical transverse isotropy (VTI) media.Since local seismic event slope contains subsurface information,they ca