The Sandbody Evolution of ShallowWater Braided River Deltas in the Eighth Member of Shihezi Formation in Block Su120 , Sulige Gas Field

Key words: 
• Sulige Gas Field /
• Blok Su120 /
• the eighth member of Shihexizi Formation(He8) /
• shallowwater braided river delta /
• sedimentary evolution

Abstract: Based on core observation, analysis of electrofacies, sedimentary facies section and sand body distribution, the eighth member of Shihezi Formation of Block Su120 in Sulige gas field pertains to shallow braided river delta subfacies. However, the development degrees of different distributary channel sand bodies are different.He81upper section develops low degree,which shows the meandering riverlike shape and pertains to the style of poorly braided distributary channel;He81lower section,He82lower section and He82upper section develop high degree,which shows the banded shape and pertains to the style of greatly braided distributary channel. By comparing these two styles, the sedimentary models of braided river deltas with different braidshaped level are established. Meanwhile, by superimposing the center line of distributary channel sand bodies of the eighth member of Shihezi Formation in this area, the inheritance and migration rules of the development of distributary channel sand bodies are obtained. The inheritance presents that the amount and location of distributary channels of different sections almost remain the same. The migration presents that distributary channels always migrate towards either side, including 3 kinds of lateral migration, namely, eastward, westward, back and forth.