Font Size: a A A

Western Sichuan Depression Research On Sedimentary Facies Of The 4th Section Of Xujiahe Formation In The Xinchang Gas Field, Western Sichuan Basin

Posted on:2012-11-03Degree:MasterType:Thesis
Country:ChinaCandidate:G LiFull Text:PDF
Abstract/Summary:PDF Full Text Request
Western Sichuan Depression Research on sedimentary facies of the 4th section of Xujiahe Formation in the Xinchang gas field, western Sichuan Basin This paper use the the 4th section of Xujiahe Formation in the Xinchang gas field, western Sichuan Basinas the target in this study. The ways are using sedimentology, petroleum geology and geophysics theory, combined with regional geological data, cores, thin section description, and logging data and seismic data of the study area. The sedimentary facies of the target area were studied in detail, and get following aspects of the results and understandings:1.The main rocks (by the rock base name)types of the 4th section of Xujiahe Formation of the study area contain lithic sandstone, lithic quartz sandstone and feldspathic, lithic sandstone,and quartz sandstone, which takes only a small part. The main feature of sandstone framework grain composition of the 4th section of Xujiahe Formation in the Xinchang gas field sandstone is rich in Lithic and poor in feldspar.The grain size of sandstone are mainly medium,fine,medium-fine and fine-medium,and coarse,medium-coarse take small part. The particles separation were good-medium,and their roundness were medium-poor,as sub-angular and sub-rounded.The main cementation types were pore type,pressure resultant and pore -pressure resultant.The main sand particles contact ways were line-bump ,followed by the line contact ways.Little point-line and bump-suture line contact ways were founded.2.Through the research of sedimentary facies of 4th section of Xujiahe Formation in the Xinchang gas field, using geological data, cores, thin section, logging data and seismic data, founde that the low section of Xujiahe formation developed fan delta plan,the middle and up section developed delta.The fan delta front can divided into fan delta plan,fan delta front and Pro-fan-delta,and the delta can divided into delta plan,delta front and prodelta.The delta front subfacies (fan delta front subfacies)is composed of distributary channel,interdistributary area and underwater natural levee,mouth bar and distal bar and so on.3.Through the researsh of the debris features variation regular pattern on pland and section of the 4th xujiahe formation of 33 wells, found that: the area contain two main material source during the deposite time--the western and north-east. The low and middle section of the 4th section of Xujiahe formation is mainly made of calcium-lithic sandstone sedimented and the up section mainly contained metamorphic-lithic sandstone, except of the CX568 wells, that means the material source of east and west are different,and material source of the low section and middle section are also different.4.Using the sublayers of the 4th section of Xujiahe formation as drawing units,the plane sedimentary facies pattern of the 4th section of Xujiahe formation was established systematically.the evolution features of the sedimentary facies distribution of the 4th section of Xujiahe formation was the result of combined action of material sources supply and lake level changes ,which were induced by the tectonic of middle section of Longmen. The main material sources suppley was from the northern,and the material sources of western and northern were possessed of evolution cycle features. The tectonic in periods in which T3X4-10T3X4-8 deposited was very strong and the main sediments was fan delta. The tectoic in periods T3X4-7T3X4-2 deposited was mitigative and the the main sediments was river delta,with the character that the front delta underwater distributary chanel and distributary bay mainly deposited, the mouth bar and distal bar were poor.
Keywords/Search Tags:New Gas Field, deposition models, the 4th of Xujiahe formation, palaeogeographic evolution, sedimentary facies
PDF Full Text Request
Related items