Abstract:

The Xinglongtai votex structure,in between the marjor Tai'an-Dawa fault and Shuangtaizi fualt,is situated slightly east of the central part of the western depression in the Liaohe basin.The pillar of strengh of this votex structure is represented by the ancient Xinglongtai buried hill and its rock slices between two rotation surfaces comprise two parts.The first one is composed of the southern and northern extremes of the Xinglongtai anticlinal strcture,accordingly being subdivided into southern and northern sets of tenso-shearing rock slices of brush structures;the second one is composed of Shuangtaizi anticlinal structure,Lengdong stepfaulting zone and approximately parallel to them arcuate fractural zone,which can be subdivided into eastern and western sets of compressoshearing rock slices of brush structures.The outer side of the rotation surface is shifted anticlockwise,while the inner side relatively clockwise.The coupling forces ensuing from the relative displacement of the Tai'an-Dawa fault and Shuangtaizi fault under the influence of the N-S sinistral shearing caused the rock mass in between them to rotate around the Xinglongtai buried hill.At the same time,Chenjia,Panshan and Qinshui synelines also shifted anticlockwise.The accumulation of the oil and gas and their changes in plan are under control of the rotationary shear stress.1) the Xinglongtai oil field,lying in the central part of the votex structure,is tectonioally the best position for oil enrichment,and the far away from it,the poorer the enrichment would be;2) while in rotation surfaces,the dissolved gas increases,the oil-gas and oil-water interfaces lowering,the quality of oil and gas bettering,and the content of methane increasing in an antielockwise order;3) the nature of the crude oil contained in the pillar of strengh is on the contrary worse than that in the surrounding rock slices between rotation surfaces;and 4) the rotation shear stress has controlled both the generation and accumulation of the oil and gas.