Seismic Reservoir Prediction And Forecast (Exploration And Prediction) In Yuan-ba Region

Sichuan basin is rich of natural gas, and it is also the the first basin which were found and to use natural gas in the world. The previous exploration shows that:Yuan-ba area has good exploration and development prospect, which is the SINOPEC’s key area of gas base construction in northeastern Sichuan, and is also the important resources guarantee to realize China petrochemical development strategy. With the exploration and development, we recognize that, reservoir is the key factor that restricts natural gas to accumulate. Reservoir in Yuan-ba area is heterogeneous, so prediction is difficult.So we use a variety of pre-stack seismic reservoir prediction methods based on AVO technology in this area, then compare and analysis the sensitivity of every abnormal attribute. Based on test block reservoir, predict the reservoir longitudinal and lateral exhibition and gas-bearing properties, analysis the geological properties of abnormal body, and make the comprehensive assessment of prediction method of reservoir. We expect to deeply understand distribution of natural gas reservoir in this area, and form hydrocarbon detection technology in this area and in the surrounding area to help northeastern sichuan area of natural gas exploration.Therefore, confirm the paper title is " seismic reservoir prediction and forecast in Yuan-ba region ". Based on the comprehe-nsive analysis of logging and geological data, through the forward modeling, studying the Xu-jiahe Formation reservoir’s AVO response of seismic data, and use the rock property determination results to take hydrocarbon detection inverseon.This is the main means to predict goal showings before drilling. In practical applications of pre-stack seismic inversion technology, AVO inversion has become one of the most effective ways looking for lithologic reservoir and get good application effect.Through establishing the relationship of reservoir fluid properties and AVO, AVO technology tests reservoir fluid property by using AVO property parameters.According to the basic data of AVO forward modeling and analysis, The basic principle of AVO technology as the theoretical basi-s.Based on the basic principles of AVO technology,r-eflection point pre-stack common gathers and velocity model gained from elaborate pre-stack data processing as a prerequisite, AVO inversion is based on gaining the changes of pre-stack seismic reflection amplitude with offset to reflect the underground lithology and fluid parameters. In particular, we have explanation about the basic principle, method and realization process in detail, and the actual data of multiple attribute parameters of the AVO inversion. This paper research content mainly includes the following several parts:The first part of the study briefly introduced the geological features in Xu-jiahe Formation reservoir area, the detailed analysis of Xu-jiahe Formation can prepare for the further reservoir prediction. Introduced the AVO technology development status, reviewed AVO technology theory and application effect these years, summarized the main problems existing in AVO Technology and introduced the research thought and technical route Briefly, described this article the main innovation.The second section of the paper briefly introduces AVO prediction method and application of gas reservoir, AVO analysis method and process.The third part of the paper studied the AVO forward modeling Xu-jiahe Formation based on the actual seismic data and well information, the establishment of three wells forward model, in which Xu-jiahe Formation shows the III AVO exception response. AVO model for fluid substitution analysis shows that it is promising to find out the III exception response with gas-bearing sandstone reservoir in this region.The fourth part of the paper is AVO attribute section of the typical wells. In the place of Yuan-ba2well, Yuan-ba27well and Yuan-ba204Well, on the poisson ratio section and fluid factors section, there are a large number of abnormal sections (yellow), and anomaly is obvious, continuity is also good. Poisson’s ratio and fluid factor are both negative anomaly, composite in P wave valley, this feature indicates that sandstone has good characteristics of gas bearing.The fifth part of the paper is research and application of the pre-stack seismic inversion technology in sandstone of Xu-jiahe Formation purpose horizon interpretation and prediction of characteristics of gas bearing, the key point is the reservoir plane distribution prediction of the upper part and the lower part of Xu-jiahe Formation. Through the plane distribution map of average negative anomaly and accumulative negative anomaly of the five kinds of attributes-poisson’s ratio, fluid factor, relative density transverse wave reflection coefficients and DHI, we can see that the concentration range of all kinds of attribute of negative anomaly is consistent and implicative.Guiding with AVO exception respond characteristics of gas-bearing reservoir of AVO forward model, through the CMP gathers after prestack time migration and treatment of AVO goal, a series of data body can be gained with AVO inversion.In this paper, the last part a complete prediction of gas distribution map is the established, for characteristics of low porosity and low permeability in Xu-jiahe Formation three wells, the use of pre-stack seismic reservoir prediction method integrated reservoir is to Identify and predict, and a gas-bearing comprehensive evaluation map is worked out, which will provide a reliable theoretical basis for the future oil and gas exploration and development in this region.Through the analysis of this paper shows that, AVO technology successfully detects the sandstone gas bearing in Xu-jiahe Formation Superficial layers sand-stone. We can find that the AVO attribute-based exception identification and method gained from AVO forward modeling and AVO inversion are relatively right, the all steps show a certain degree of verification, and it has a positive significance for AVO study in complex region. In conclusion, this paper summarized that there are a certain amount of oil and gas resources in the northeast Sichuan which have certain exploitation value.