Reservoir Prediction Of The Second Member Of Sangonghe Formation In Mahu 4 And 18 Well Blocks In The Junggar Basin

Exploration practice has proved that Mahu Sag in the northwest margin of the Junggar Basin is rich in oil and gas resources,and has the characteristics of multi-layer system three-dimensional reservoir formation.The discovery of Jurassic Sangonghe Formation oil reservoirs in Mahu X and Y well areas in recent years marks a significant breakthrough in shallow exploration in the basin.In order to deepen the understanding of the characteristics of shallow reservoirs and the distribution of sand bodies,and implement the goal of increasing reserves and production,this paper adopts the method of combining well and seismic data,using well area geology,logging,and seismic data to carry out comprehensive reservoir research and sand body prediction,providing technical support for shallow oil and gas exploration and development.The following understanding was achieved:（1）Structural interpretation is conducted using seismic data from the Mahu X and Y well areas,synthetic seismic records are produced,and detailed horizon interpretation is carried out.Starting from the fault section,with the aid of coherence cube technology and time slice,determine the development of J₁s₂⁴ fault elements and top structural features in the study area.（2）Based on the principles of sequence stratigraphy and modern sedimentology,sequence identification and division of the Sangonghe Formation were carried out,and a single well sequence division model was established.Using logging curves and core data,J1s24 was divided into two sub layers,J₁s₂^4-1and J₁s₂^4-2,from bottom to top.Stratigraphic division and correlation of 90 wells in the study area were completed.（3）Conduct research on sensitive parameters of reservoir characteristics,and research shows that wave impedance curves,natural gamma curves,and natural potential curves can be used to identify reservoirs.The lower limit of wave impedance is 8000（g/cm³·μs/ft）,the overall performance of the reservoir section is high;The upper limit of reservoir natural gamma is 48 API;The lower limit of natural potential amplitude difference is 10 mv.（4）Selecting wave impedance curves for waveform indication inversion;Through waveform indication simulation of natural gamma and natural potential curves,a seismic inversion body reflecting the distribution of sand bodies was obtained.Its profile and plane characteristics were verified by development and production,and the prediction accuracy of oil-bearing sand bodies reached 77%,indicating that the seismic reservoir inversion results were reliable.