Fine Structural Interpretation And Structural Modeling Research For Complex Fault Reservoir

Pucheng Oilfield of Wen 51 fault block is located in the central uplift belt in northern Pucheng and Wenliu’s structure combining part of Dongpu Depression. The block tectonic movement occurred many times, developed a multi-phase secondary faults, and formed a complex structural pattern. Especially Wen51 south block structure is extremely complex, near the east-west cross-sectional layer more,and the master fault Wen 27, Pu 92 fault cutting is not clear and difficult fault combination,cross layer and the main controlling fault cut out 9 small fault block, in addition each small block have internal secondary minor faults. These secondary small fault occur vague understanding, resulting in poor correspondence between injection and production. Therefore, to carry out the fine structure interpretation and modeling of complex fault blocks, having important significance on a clear understanding of the block and carry out structural characteristics and residual oil reservoir modeling study.Under the high accuracy sequence stratigraphy theoretical guidance, thesis conducted stratigraphic correlation and classification, achieved a closed formation region and implemented a large number of breakpoints. With the synthetic seismogram for the bridge achieved a fine calibration of seismic and geologic horizons region horizon tracking, and on this basis, summarized the main features of the interface seismic reflection horizons. Under the guidance of oil tectonic theory of the formation mechanism of fracture, fracture development law,tectonic style, a combination of the principles of the breakpoint, the breakpoint combination of flat and profile, etc. combining the time slice and the coherence technique for fault interpretation, meanwhile applied RFT, fluid properties, dynamic information and verify the reasonableness of the relationship between water and gas structures, further modification and perfection have been explained structure.Finally the application of stack velocity spectrum data,the establishment of the 51 blocks of 3-D velocity field,strain degree graph main sand group of top structure.On the basis of fine interpretation of the structure of the study area, tectonic fracture features and configuration have been analysed. Summary of Wen 51 fault block tectonic features of Wen 51 fault block is Pu 24 fault segmentation into North and south two fault block, North block as a whole syncline structure morphology. At the same time the north south southwest anticline form has been uplifted; South complicated block structure, secondary small faults was divided into 9 small oil-bearing block. The fault block can be divided into three groups according to the fracture systems:①the NNE trending Weidong (or the East)-Wen 51 fault system;②the North East to the south of Pucheng-Pu fault system; ③sectional system nearly east-west. Combination section fault mainly in the ladder and the "Y" font based.Simultaneously, according to the structural history profile and fault activity time, at all levels of fault reasonable cutting relationship and tectonic evolution history was studied. The 51 block structure determines the evolution can be divided into four stages: ①the initial depression:formed two wa a long initial pattern of Dongpu depression, when Wei Xi, Pucheng West dipping fault generated, then a strong activity, and the East inclined formation of reverse roof breaking order tectonic belt.②the deep-atrophy stage:at this point the Wei Xi Pu fault and South West off the intensity of fault activity gradually weakened until it stops, two stage Weidong fault sand began development and intense activity, cutting the Wei Xi, Pucheng fault, in the downthrown side of ET form the reverse compensation fault, the formation of graben tectonic style; sand two to sand sedimentary period in the study area, structure form the basic shape, only a few fault continued weak growth.③the decline phase:Lake sharp shrink and die, the end of the early third age all development history.④in the period of depression:into the depression deposits entered the stage of the whole study area, fault movement in the basic stop, had formed the tectonic style setting and preservation.Complex fault block reservoir has the characteristics of multi faults, complex contact relation, for complex fault block reservoir, tectonic modeling core is to set up fault model. Tectonic model is true and accurate reflection of fault contact relationship and stratum structure of occurrence for the simulation of remaining oil distribution is very important. The complex relationship between contact fault is always a big problem in complex fault block geological modeling.The application of petrel software,combined with the 51 fault block tectonic characteristics,a detailed study of the complex fault block reservoir in the process and method to establish the structural model,and summarizes the modeling steps should pay attention to detail and in the process of modeling the problems and techniques.At the same time, summarized the processing method of connecting, truncation relationship between the layer block structural modeling process interrupt complex fault, and constructed a model of grid and some solutions to the problems. Proposed according to the pattern of whole fault model and fault cutting relation, by adjusting the fault trend and set the trend line, to improve the grid quality objectives; and check the quality from three aspects:①to check the tectonic model of the faults and strata occurrence is consistent with geological knowledge;②hierarchical data in order to ensure the construction level and Inoue anastomosis; ③in order to check the quality of grid number die whether meet the requirements.The study area has a good effect in the application of the above technique.