The Study Of Distribution Rule Of Reservoir Fractures On The Supper Shaximiao Formation In The Wubaochang Gas Field

Wubaochang gas field belongs to Northeast Sichuan basin which is located at the southwest side of Daba arc tectonic belt and the north of East Sichuan detachment fold belts in northern margin of Yangtze Block. This region was effected strongly by cracking and merger of plates during the history, the collision and splicing of different micro-plates in different periods, and intraplate thrust orogeny for one after another, whose superposition and compound formed a very complex structural pattern. Sedimentary cover on the Wubaochang basement is completely developed, the formation from Upper Triassic Series of Mesozoic group to Cretaceous are all clastic sedimentary. With the constant improvement of oil and gas exploration degree, compacted and low permeable fractured reservoir of the supper Shaximiao formation in the Wubaochang gas field has become an important exploration areas.Therefore, the rule of distribution of reservoir fractures is imperative, as one of the important research topics on oil exploration in the region.Based on Fully grasping and digesting a large number of studies that have been done, combined with the purpose of this study, guided from structural geology, sedimentary petrology, logging, seismic and other related theories, we use the method that points combined with surfaces, micro combined with the macro, and completed the following aspects: 1. Sequential analysis of the structural characteristics and style in the study area, and its control of fractures on the supper Shaximiao formation. 2. Crack detection from the special processing data of logging data, logging response characteristics and three-dimensional seismic. 3. Comprehensive analysis of the fractures plane distribution characteristics on the upper Shaximiao formation by structure geology, fracture prediction, drilling, logging and production performance data. The technical idea is: we study the control of structures to fractures by analysis of the tectonic setting, northeast regional structure and Wubaochang structure; we statistical and theoretical analysis the factures attitude through field observations, logging data analysis, drilling cores observation, and microscopic observation; fractures evaluation through a variety of logging methods; fracture detection through special processing of seismic data and interpretation of seismic data; comprehensive analysis of fractures distribution characteristics.Though the study of distribution rule of reservoir fractures on the supper Shaximiao formation in the Wubaochang gas field, we achieved with the awareness of the following main results:(1) The supper Shaximiao formation in the Wubaochang gas field can be divided into four sub-Shaximiao section by sedimentary cycles from bottom to top, the section Sha21 at the bottom that often be called Shaxiangzhai sandstone, is the main gas sand in the supper Shaximiao formation.(2) Sha21, Sha22, Sha23 are typical sandstone reservoirs with low porosity and low permeability, there aren't industrial gas output if only depend on pore of block-based hard rock.(3) Complex stress field controls the fracture system of Wubaochang gas field. Most of the faults in the field are small, extending a short distance without causing obvious detrimental effects on the trap, and have an active role in the improvement of reservoir conditions.(4) Crack distribution and logging response characteristics of the the supper Shaximiao formation in the Wubaochang gas field are that depth laterolog turn up to the positive or negative difference in the fractured section(5) The distribution of fractures on the supper Shaximiao formation could be summarized for 4 ~ 5 North West - South East irregular fracture zone from north to south.