A Study Of High-resolution Reservoir Predication Application In Z Area

Lithologic reservoir has become the focus of oil and gas exploration in China.There is some data show that the lithologic oil and gas resources in Dzungaria basin are huge, so it is an important area of onshore oil and gas exploration. Z area is located in the central part of Dzungaria basin, the structure of the region is relatively simple and shows a good view of exploration. The main reservoir in the area Z layer belongs to braided river delta plain-front deposits with the characteristics of thin thickness, buried deep, strong heterogeneity and difficult to make reservoir prediction.Besides, there are seismic data shows that the upper part of target has a set of mudstone cap rock which is stable, and it can cause a strong reflection in the seismic record which shield the lower reservoir reflection so that the reflection of the reservoir is weaken and become difficult to identify. It is difficult to achieve satisfactory results and meet the needs of fine description of reservoir by conventional reservoir prediction techniques. Therefore, it is important to explore a targeted technical means to carry out high resolution reservoir prediction in Z area and to provide guidance for the next step of exploration and deployment.Aiming at the issue in Z area, taking geology, sedimentary, well logging and seismic information as a guide, some effective information about seismic data has been excavated deeply. First of all based on the existing measurement and geological data, geophysical response characteristics of the reservoir in the Z area has been studied through forward, and as a basis for carry on improving the resolution of seismic data after stack. This thesis introduces the commonly used multi-wavelet decomposition and reconstruction technique, and upon this theory the improved multi wavelet decomposition and reconstruction to eliminate the strong reflection technique is presented and the model test proves the feasibility of this technique. The practical application in the actual seismic data shows that this method can remove the strong reflection in seismic data, eliminate the influence of shielding weak signal’s effect,and highlight the energy of the weak reflection of thin reservoir. Then some common frequency expanding technologies which can improve vertical resolution of seismicdata are contrasted and the suitable one is selected, and the effective frequency band is widened in the seismic data after removing the strong reflection. The processing results proved that the resolution of seismic data of Z area can be effectively improved by combine this two method, and also highlight the weak reflection signal of thin reservoir. Constraint sparse spike inversion and seismic attribute technique is being used to identify and predict the reservoir on the basis of improving the resolution of seismic data. Through seismic attributes analysis and inversion analysis the main reservoir characteristics in J1s21 in the Z area is verified, and the fine description and prediction of the 2 layers main reservoir are carried out. Finally, we predict that the northern part of the Z area is the favorable reservoir distribution region.In this thesis, a set of targeted reservoir prediction technology is proposed by a case study of lithologic reservoir exploration of tight thin reservoir in Z area, and this technology can provide some ideas for the prediction of reservoirs with similar characteristics.