Structural Characteristics And Its Control To Sedimentation Of Qingshankou Formation In Qijiabei Area, Songliao Basin

The Qingshankou formation has major potential of bearing hydrocarbon resources in Qijiabei area, Songliao basin, but its fine geologic research is still comparatively weak. At the base of predecessors'study, guided by structural geology, sequence stratigraphy and sedimentology, comprehensive utilization of seismic, core, and log, well logging, analyse and laboratory test, the structure, sequence and depositional system's feature of Qijiabei area were researched systematically, and the structure to deposit's control action was also analysed. That's important for this area's reservoir prediction and favor hydrocarbon enriching areas'optimize.Begin with the 3D seismic data structure explanation, the growth fault's geometric and activity feature which developed in Qingshankou formation were quantity studied, and the genetic mechanism of the fault was also analysed. Through composing balanced section, the history of structural evolution was resumed. In Qijiabei area, Qingshankou formation, a large number of small scale growth fault developed, their fault sections were steep, present as apron type, their assemble style mainly was graben. Fault is not distribute evenly in plane and section, and their activities are much different. In east the fault developed large number, with intense activity. In west the fault developed few numbers, with weak activity. In Qing1 section and Qing2 section, the fault has large number, with intense activity, and In Qing3 section, the fault has fewer numbers, the activity also became weak. During extend acting process in the direction of NEE-SWW in the early stage of Qingshankou formation, the former fault in the direction of NNE developed transtensional movement. That leads its overlying formation occurred extension fracture, then fault formed.Multipurpose utilization of core, log and seismic, the high definition sequence of Qingshankou formation in Qijiabei area was divided. Qingshankou formation was divided to 1 long- term cycle, 6 middle period cycles and 18 short-term cycles. Using the method of associated of well and seismic, use the middle period cycle as correlation of strata unit, the sequence correlation of strata was done. The sequence strata framework of Qingshankou formation in Qijiabei area was build.Through the observe of core and thin slice, fractional analysis, the study area's sedimentary facies'type was defined. Qingshankou formation in Qijiabei area, develops delta facies, lake facies and slump Hackberry facies, subfacies mainly was delta front subfacies, whose microfacies are underwater by channel, mouth bar and sand sheet. Each subfacies'depositional model was build up associated with the feature of log response. Through integrate decide of heavy mineral data analysis, sandstone percentage composition analysis and seismic reflection configuration analysis, the study area was controlled by north resource, and its native rock's type mainly was acidic magmatic rock. Based on above study, this paper proceeded cut plane facies comparison and plane facies analysis, also revealed this area's depositional system's distribute law in time and space. The analysis showed that the action of growth fault has apparently control action to the formation thickness, the sedimentary facies type and its 0distribute direction and the development of seismites and volcanic rock.