Optimization technique of development well pattern of shale oil in Ordos Basin and its application:a case study of Qingcheng oilfield
The shale oil reservoirs in Qingcheng oilfield,located in Ordos Basin,are characterized by multiple periods of vertically stacked oil layers and strong lateral heterogeneity,making it challenging to optimize the development well pattern.Based on consid-ering the geological characteristics of shale oil reservoirs in Qingcheng oilfield,and comprehensively using the methods of oilfield ap-plication,reservoir engineering and numerical simulation,a systematic study was conducted on the orientation,length,well spacing,three-dimensional well pattern development,and reasonable stratification of the horizontal section,so as to maximize the utilization of reserves.The results show that the main orientation of horizontal wells should be perpendicular to the maximum principal stress direction;however,taking into account the distribution direction of sand bodies,the utilization of underground reserves,and the lo-cation of surface well site,the orientation of wells in horizontal section can be appropriately deviated in the target front area and re-stricted surface area.The optimal length of horizontal section is mainly 1 500 m,and the length of the horizontal section affected by the extension of sand body is within the range of 600m to 800m.The optimized controllable reserves per well is(25-30)× 104 t,and generally the well spacing is 500 m;there are various deployment areas in the oil layers of different thickness.The three-dimensional development technique is applied for the oil layers with a vertically stratified thickness greater than 10 m.Based on the above study,a three-dimensional well pattern has been established for the multi-layered shale oil reservoirs.The research results present a single well estimated ultimate recovery(EUR)of(2.6-2.8)× 104 t and an annual oil production of 165 × 104 t in Qingcheng oilfield,achie-ving large-scale efficient development.
Ordos BasinQingcheng oilfieldshale oildevelopment well patternoptimization techniqueapplication
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