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Research And Application On Detection Technology Of Hydrocarbon Layer For High Temperature And High Pressure Reservoir In Dongfang Area,Yinggehai Basin

Posted on:2017-05-14Degree:MasterType:Thesis
Country:ChinaCandidate:W W LiuFull Text:PDF
GTID:2180330482491912Subject:Earth Exploration and Information Technology
Abstract/Summary:PDF Full Text Request
In recent years, two large commercial gas reservoirs, DF13-1 and DF13-2, have been found in the high temperature and high pressure formation of Yinggehai basin. Once the HTHP reservoir contains gas, the velocity of seismic wave in it will reduce faster than that in mudstone caprock, and seismic bright spot will also show in the top surface of the reservoir. Under the influence of HTHP, seismic reflection information will be greatly different from the characteristics of conventional gas reservoir. The same geological conditions may correspond to different seismic reflection and vice versa. And the actual drilling results in DF13 field show that not only gas layer but also dry layer and water layer perform as bright spot.In order to further analyze the relationship between reservoir characteristics and seismic reflection, this paper establishes the relationship between rock physic al parameters of the HTHP reservoir and the intensity of seismic reflection based on well logs, rock physical analysis and core experimental data. And this provides a preliminary theoretical framework for reservoir prediction and fluid identification. In the process of logging rock physics analysis, this paper uses the total porosity derived from neutron log and density log to build a bridge between reservoir physical property and seismic wave impedance. Using the "excavation effect" characteristics of the neutron porosity, the gas bearing properties can identify by the difference of gas corrected density and measured density, and the distribution of gas reservoir will determine by the positive difference inversion.It is well known that pre-stack density inversion requires for high quality of seismic data. Because of complicated geological conditions like deep buried depth and low speed mud rock, offset gathers from the HTHP reservoir have such problems as low SNR, uneven seismic event, wavelet distortion and trace gathers distortion. This paper optimizes the pre-stack seismic gathers in DF area through improving SNR and resolution, suppressing random noise and coherent noise, removing multiple wave and residual dynamic correction time differences. With thus optimized gathers, the inversion result becomes more accurate and the density difference which can effectively identify and predict the distribution of gas reservoir and eliminate false bright spot has a better display in seismic section. This method plays a key role in determining the reserves in DF13 area especially in non-well area and also makes a big step forward in the HTHP reservoir hydrocarbon detection.
Keywords/Search Tags:HTHP reservoirs, Rock physics, Pre-stack inversion, Difference density, Hydrocarbon detection, Yinggehai Basin
PDF Full Text Request
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