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Seismic Prediction Of Deep Marine Carbonate Reservoir In Westregion Of Sichuan

Posted on:2013-11-09Degree:MasterType:Thesis
Country:ChinaCandidate:H K DuFull Text:PDF
GTID:2230330377950005Subject:Earth Exploration and Information Technology
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There are quite plenty of potential natural gas resources in western Sichuan. But thisarea is still relatively unexplored due to the characteristic of carbonate reservoir. Thecarbonate reservoir in western Sichuan is buried deeply and controlled by manyfactors. And there are many types of reservoir obvious homogeneous in this area.Those factors have brought immense difficulty in predicting and appraising thereservoir. So far, there has been no effective seismic prediction technique aimed at themarine carbonate reservoir in west region of Sichuan. It has severely hindered itsfurther development.The sedimentation and seismic response of carbonate reservoir in westernSichuan have certain specificity although the reservoir is complicated andhomogeneous. For the characteristics of the carbonate reservoir in western Sichuan,The thesis starts by the characteristics of sedimentation and seismic facies andcompletes the tectonic interpretation and sedimentary facies study by using acombination of petroleum geology, sequence stratigraphy and sedimentology theoryand methodology. Using the method above, the relationship between seismic faciesand sedimentary facies can be established and the favorable sedimentary facies beltfor the development of reservoir can be divided. Then the distribution regularity ofreservoir can be predicted by using the seismic facies characteristics of the carbonatereservoir and the technique of seismic attribute extraction and seismic facies analysis.The seismic data the paper used is provided by Sinopec and includes212D seismiclines covering the entire western Sichuan and3combined3D seismic data.This study shows that the depositional environment in western Sichuan wasmainly rimmed carbonate platform from Permian to Middle Triassic. Its depositionalmodel properly corresponds with the tucker’s, could be divided into severalsedimentary subfacies, including evaporate platform, restricted platform, openplatform, platform margin reefs, platform margin shoals, slope and shelf. It is pointed that platform margin, open platform and restricted platform with shallow water bodyand strong water dynamic are the favorable sedimentary facies belt for thedevelopment of reefs and shoals by analysis of reservoir types and controlled factors.The reefs and shoals only deposited on the ancient geographic highland might betransformed by leaching of meteoric water and dolomitisation due to early exposure.So the ancient geographic highland located at the favorable sedimentary facies belt issuitable to the development of good reservoirs and is the favorable areas to find thelarge-and/or moderate-sized reservoirs. Searching of reef and shoal reservoirs by thetypical seismic feature of reefs and shoals can improve the accuracy and reliability ofreservoir prediction. Meanwhile, it can be compared and validated byfrequency-division and technique of seismic facies analysis. Finally, we can map thespace distribution of the likely reservoir.The results showed that in Changxing formation of Upper Permian open platformand mixed tidal flat-restricted platform were the main sedimentary facies and the reefswere likely developed in Majing-Pixian, Zhongjiang and Mianzhu. In FeixianguanFormation in Lower Trassic, open platform and restricted platform were the mainsedimentary facies and ooid shoals were likely developed in Beichuan-Jiangyou,Mianzhu and Dayi. In Member1and2of the Lower Triassic Jialingjiang Formation,open platform and open-restricted platform were the main sedimentary facies andshoals were likely developed in Hanwang-Anxian-Zhongjiang-Majing and Dayi. InMember3,4and5of the Lower Triassic Jialingjiang Formation,restricted-evaporative platform were the main sedimentary facies and shoals werelikely developed in Deyang-Majing, Mianyang, Mianzhu and Hanwang-Jiangyou. InMember1and2of the Middle Triassic Leikoupo Formation, platform edge andrestricted–evaporative platform were the main sedimentary facies and platformmarginal shoals were likely developed in Mianzhu-Shijin, Hanwang-Jiangyou andDayi. In Member1and2of the Middle Triassic Leikoupo Formation, platform edgeand restricted–evaporative platform were the main sedimentary facies and platformmarginal shoals were likely developed in Hanwang-Jiangyou, Dayi and Majing.In conclusion, use of above methods can predict the distribution of the reservoirsmore accurately and carried on preliminary appraisal of the reservoir distributedcharacteristic in researched area. It can provide evidence for drilling deployments andachieves the goal that guides the oil and gas exploration.
Keywords/Search Tags:reefs and shoals, seismic facies, sedimentary facies, comprehensiveprediction
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