| During later Paleogene and early Neogene, Jiyang Depression undergone from rifting activity to depression activity. During early Guantao Formation, fault active, highland eroded, slope overlapped and sags filled, and then when later Guantao Formation begin sedimented, paleotopography became plainness, new stratum overlaid all old stratum, intensity of fault activity gradually got in weaken, and developed the sedimentary system of alluvial-fluvial-freshwater shallow lake. All those factors made rock source-reservoir-cap excellently assembled in Guantao Formation. This paper studied fault activity characteristics and intensity of fault activity, numerically simulated palaeotectonic stress field, studied how and what extensive faulting activity controlled stratigraphic sequence and sedimentary system, studied the pool-forming element of Guantao Formation, and the established reservoir forming model of Guantao Formation. Finally, this paper mainly focused on how faulting activity and paloetectonic stress field controlled Guantao Formation pools or reservoirs forming. Some advices for future exploration of Guantao Formation in Jiyang Depression were also proposed in this paper. The primary innovations showing as follows:1 Based on the interpretation of thirteen seismic section, ninety-three active faults in early Guantao Formation, and seventy-five active faults in later Guantao Formation were revealed, both fault growth index and palaeo-fault throw methods were used to analysis faults activities, and the evidences showing fault active features: in Jiyang Depression , intensity of fault activity of early Guantao Formation is greater than that of later Guantao Formation ,and that of boundary is greater than interior. As a whole, in the early Guantao Formation , intensity of fault activity is: Chezhen sags > Huimin sags > Dongying sags >Zhanhua sags. From the early Guantao Formation to the later Guantao Formation, faultactive move form south to north in Dongying sags and Zhanhua sags, but from north to south and west to east in Huimin sags.2 Applying combined methods of the regional tectonic setting analysis and structural patterns, palaeotectonic stress field directions of early Guantao Formation later Guantao Formation and Minghuazhen Formation in Jiyang Depression were confirmede. Applying the estimate of similar geologic condition between nowadays and geologic history, and combining measuring result from acoustic emission, estimated the range of size of paletectonic stress field in early Guantao Formation, later Guantao Formation and Minghuazhen Formation. By the above restriction, through the method of finite element numerical simulation, respectively model palaeotectonic stress field of early Guantao Formation, later Guantao Formation and Minghuazhen Formation. In early Guantao Formation, minimal principle stresses all were tensile stress (0.1 ~3.7MPa), and the maximal principle stress all is compressional stress, in general, horizontal shear stress show the character of sinistral displacement. The maximal principle stress in Huimin sags is SN-NNW direction, others are NEE or NE direction. In later Guantao Formation, compression is primary, the maximal principle stresses no more than 0.1 MPa, and in central of Jiyang Depression horizontal shear stresses are dextral displacement, but sinistral displacement showed in west and east. In Minghuazhen Formation, the region of tensile stress shrinked to north-east place Zhanhua sags and region of Chengbei of Jiyang Depression, dextral displacement in central of the Depression, and sinistral displacement in boundary sides both west and east, and direction of principle stress approaching nowadays , that is maximal principle stress near EW.3 Based on the differences of reservoirs forming conditon and oil-gas transforming system, Guantao Formation of Jiyang Depression oil-gas reservoir forming models can be constructed as three types and four kinds: the model of uplift zone, the model of faulted zone and the model of slop zone, and the model of uplift zone also be subdivided into double-faulted and single-faulted uplift zone pool forming model, that is three types and four kinds.4 The oil and gas pools of Guantao formation are all external-source pools. The faults are main channels of vertical migration of oil and gas. Main framework of fault of the basin controls the vertical and plane distribution of oil and gas. Drape anticline, fault nose, fault-block tectonics and lithologic pinch-out traps are main trap types of Guantao formation. At the same time, fault activity also controls the oil and gas property in the pools. Some areas where the activities of main fractures are weak, the number of shallow faults is few, andsediments of paleogene are extremely thick, so hydrocarbon migration and accumulation is difficult, viscous-crude pool were mainly pools.5 Palaeotectonic stress field not only controls fault activity, but also controls the formation, distribution and development of oil and gas pools. The magnitude and direction of stress control the dominant orientation of hydrocarbon migration and accumulation. In tensile stress trend region, mature crude oil give priority to vertical migration. In compressive tectonic region, just when average total stresses exceed some value, does stress field play a key role to hydrocarbon migration and accumulation. Oil and gas migrate from the low value region of the maximal principle stress to the minimal principle stress region to form petroleum pool.6 The pool-forming patterns and the control functions of fault activity and stress field to pool-forming is integrated. It is predicted that the beach area of Jiyang sag is the main area of next petroleum exploration. Increasing the exploration strength of Linfanjia uplift of Guantao formation is suggested. The growing activity of main fracture of central uplift belt of Dongying and Huimin sags belong to pool-forming pattern of fracture belt. Oil and gas transportation give prior to stair-stepping transportation. The viscous-crude pool of Guantao formation is fragmentary distribution. Dongying sag slope is advantageous oil and gas region where Gaoqing area is representational of Guantao formation.
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