Fuyu Reservoir Characteristics And Prediction Of Crack Xingshugang Areas

Low permeability reservoir is an important oil and gas reservoir type of continental sedimentary basin, and its reserves is accounted for more than1/3of the total reserves of oil and gas resources China’s current proven mining, of which more than70%is the low permeability sandstone reservoir. Fuyu reservoir in Xingshugang are well developed, cracks is the main channel of the oil and gas seepage,which is also an important reservoir space, the reservoir cracks development directly affect the exploration and development of oil and gas. The paper combines the theory of structural geology, reservoir geology and sedimentary petrology, to study the fracture characteristics of Daqing Changyuan Xingshugang area reservoir, combines with the finite element method to predict the development of fractures, and ultimately determine the effectiveness of Xingshugang area Fuyu reservoir fracture. The paper agained the following achieved and understanding:(1) The observed results of core cracks is the most basic data and most reliable evidence for cracks prediction, reservoir crack in Fuyu of Xingshugang are most is upright seam,which inclination is Greater than or equal75°, the proportion is more than75%.another, high angle cracks,which inclination of45°-75°is about15%, low angle joints and horizontal seam is very rare. Mesoscale cracks accounted for more than60%of the total number of cracks, the large-scale cracks accounts for about20%, the crack width is mainly concentrated in the range of0.1-lmm, accounting for more than55%of the total number of cracks, crack density is mainly distributed in the0.01-0.03crack/meter, accounting for about60%of the total number, half-filled and unfilled cracks accounted for about70%of the total number, full-filling is about20%.(2) Use of qualitative methods and finite element numerical simulation method to predict development degree of cracks in the study area. From the the qualitative forecast results of the geological method, the cracks developed area located in70wells and nearby faults Interchange,Xing76wells, Xing7-4-geng22wells, Xing Fu71-3wells,Xing8-2-524well regions, Xing6-2-geng123wells, Xing Fu71-1wells, Xing67wells; tectonic stress field simulation results show that the cracks developed area is located in Xing Fu71-5wells, Xing Fu71-Xie11wells, Xing9-2-518wells, Xing Fu71-3well area, Xing4-3geng bing-13wells, Xing Fu71-1well area, as well as Xing69wells range.(3) Combination of the above results, study for the Xingshugang Fuyu cracks,cracks in areas which is not filled and half filled is accounted for about50%of the total number of cracks, contribute to the effectiveness; maximum principal stress direction in study area mainlyeast to North East, the cracks in the study area is near North East,it can be seen, angle between the near the North East cracks and maximum principal stress direction is same, which is conducive to keep the cracks open. Meanwhile. Angle between North West and the maximum principal stress direction also is very small, effectiveness is perfect. With the current parallel to the direction of stress cracks NE seepage best, but as development proceeds, the formation pressure drop, different groups based fracture permeability changes should be used as the basis for the late pattern adjustment.