Sedimentary Facies Of Changxing Formation In Upper Permian， North Area Of The Southeastern Sichuan Basin

The development of the northern region of the southeast Sichuan PermianChangxing Formation in a marine carbonate sediments, the area producing gasreservoir, through the many years the research work of many experts and scholars inthe area of sequence and sedimentary facies characteristics have an initialunderstanding. In this paper, previous research results, drilling and logging datacollected (including the six new wells) and three-dimensional seismic data in the areaa more refined sequence and sedimentary facies portrayed.Through the study of sequence stratigraphy, the Changxing Formation can bedivided into two three-layer sequence, and six four sequence, two three-layersequence are mainly preserved transgressive systems tract and highstand systemstracts and transgressive systems domain of deposition thickness was significantly lessthan the thickness of the deposition of the highstand systems tract; vertical on thedevelopment of several sets of reef, shoal dolomite reservoir, the reservoir is mainlydeveloped in the two HST, and its distribution is mainly affected by sedimentarymicrofacies and diagenesis control Types of sedimentary facies of the work area canbe divided into the carbonate platform facies and slope relative to the platform faciesof carbonate rocks can be divided into the development of an open platform andplatform margin two sub-phase, open platform bioclastic through the study of thesedimentology development of biological Beach and platform margin reef (Beach),bioclastic beach, tidal flat equality is favorable reservoir facies. The standpoint of asingle well sequence and sedimentary facies and sequence stratigraphic framework,and deposition compared to the sequence stratigraphic framework, analysis of thecharacteristics of the Changxing Formation in profile horizontal and vertical pairs theformation of the geological processes have a more profound understanding of theChangxing Formation of sedimentary facies pattern established on this basis. To carryout seismic facies of regional seismic facies sedimentary facies plane distributionprovides an important guiding role; local seismic anomalies before the plot,hummocky and wavy, beaded brow like a strong amplitude, stratigraphic onlap pinchout five prediction of reservoir distribution. The use of single well integratedlike sedimentary facies deposited map and sequence stratigraphic frameworkcompared to the plan to the three system tracts as a unit, the preparation of asedimentary facies plan to carry out the reef flat planar distribution characterizationand sedimentary facies research.Reservoir prediction of sedimentary facies for beneficial micro-seismic facies isabnormal body of favorable reservoir, combined with the ancient geomorphologicalfeatures, impedance inversion, seismic amplitude, oil and gas detection results of thedivision cycle divided in the Changxing Formation five favorable exploration area,divided into six favorable exploration area in the Changxing Formation cycles.