| The beach area of Liaohe Oilfield is located in the northern part of Liaohe-Liaodong bay basin. It is the continental fault depression which is formed under an extensional, strike-slip background during the Mesozoic-Cenozoic period, and it is the transition zone between the Liaohe depression and Liaodong bay. The study of sedimentary facies and sedimentary characteristics of the First and Second Member of Dongying Formation in the estern beach aera of Liaohe Oilfield is confined by the limitition of natural conditions, geologic conditions and degree of exploration. To figure out the confusion of the sedimentary facies and its distribution of the study aera, it is essential to establish the suitable sequence stratigraphic framework according to the special local geologic conditons. Then the sedimentary characteristics, sedimentary facies and sedimentary model of the study area can be concluded under the framework of sequence stratigrahy which can offer a new idea for the further exploration and research.Core facie, log facies and seismic facies of study aera are established by the analysis of the seismic data, the interpretion of log , the observation of core and the study of related former reserch. Then the sedimentary facies and its characteristics can be identified by the comprehensive study of core facies, log facies and seismic facies. The research shows that there are three major sedimentary faices in the First and Second Member of the Dongying Formation in the study area: braid delta, delta, and beach-bar. The beach-bar is first found in the study aera and points out a new diretion for sedimentary research and future exploration.The map of sedimentary facies distribution of different period of the Dongying Formation can be pictured, by the comprehesive study of single well analysis(ponit)-well tie section analysis(line)-sedimentary distribution range (plane)-local geologic conditons(backgroud). Small scale destructive delta, braid delta and large scale beach-bar are developed in the Second Member of Dongying Formation, with the explandition of the lake range, falling water level and the decreasing of sediments supply. As affected by the continuance of the falling water level and the structral movement, large scale of delta is developed in the Lower First Member of Dongying Formation and large scale of braid delta is developed in the Upper First Member of Dongying Formation.By the study of palaeogeomorphology, we can ponit out that there is a good relationship between sedimentary facies and palaeogeomorphology, and palaeogeomorphology control the distribution of the sedimentary facies and the sandbody. |
