鄂尔多斯盆地高闭合应力致密砂岩储层现今地应力场分布特征及扰动规律OA

Tight sandstone reservoirs with high-closure stress are significantly impacted by complex lithological structures and faults,and the challenges associated with unclear stress distribution patterns and poor post-fracturing performance severely hinder breakthroughs in oil and gas production from these formations.To clarify the in situ stress field disturbance characteristics in tight sandstone reservoirs and address the issue of low oil and gas production after fracturing in high-closure stress reservoirs,this study focuses on the He 1 member of the Niuwu block in the Fuxian area.By applying technologies such as core testing,logging calculation,finite element simulations,and fracturing simulations,a three-dimensional detailed heterogeneous structural model was constructed to determine the distribution characteristics and influencing factors of the current stress field.Based on the results from a single-well productivity analysis,this study also proposes favorable well locations for deployment.The results show that the maximum horizontal principal stress in the Niuwu block is primarily oriented NE-NNE,with stress values displaying a trend of higher stress in the east and lower in the west.The stress state belongs to type Ia(σv>σH>σh>0).Lithology predominantly controls the overall stress field distribution in the tight sandstone reservoir and is the main cause of the uneven stress distribution in non-faulted areas.In contrast,the fault morphology,combination patterns,and orientations significantly affect the stress distribution and direction in local areas.It is recommended that well locations be prioritized within the range of 0.25～0.80 km from the north-east to east-west faults,with horizontal trajectory deviations ranging between 125°～150° SE.These research results provide effective support for the subsequent optimization of development units in these high-closure stress dense sandstone reservoirs,with the aim of steadily increasing the economic output of single wells therein.