Application of Integrated Geology and Geomechanics to Stimulation Optimization Workflow to Maximize Well Potential in a Tight Oil Reservoir, Ordos Basin, Northern Central China

摘要

The development of interbedded and highly heterogeneous Chang7 tight oil sandstone reservoir in Ordos basin in northern central China encountered major challenges. Initial development by massive hydraulic fracturing of horizontal wells yielded unfavorable results with many low productivity and uneconomic wells. This placed a big question mark on viability of development of the gigantic tight oil reservoir in Ordos basin with reserves up to multiple billion barrels. Detailed analysis of existing wells revealed that lack of geological and geomechanical understanding of the highly heterogeneous reservoir hindered effective stimulation optimization. In searching for the recipe to boost the production performance of the reservoir, a new integrated stimulation optimization workflow was applied to a pad in the field. The workflow started from construction of 3D geological model based on offset vertical wells and image data and log data from horizontal wells. Then, 3D geomechanical model was built to determine 3D distribution of mechanical properties and in-situ stresses. Based on the 3D geological and geomechanical models, an optimized stimulation strategy was developed that had the best fit to the geological characteristics of Chang7 tight oil reservoir.