Abstract
Due to the advances of horizontal drilling and multistage hydraulic fracturing technologies, the utilization of tight oil resources has become a world focus in global petroleum industry. The performance forecast is significant to determine optimal well spacing and optimum drainage areas within and beyond the stimulated reservoir volumes (SRV). Multiple hydraulic fracture treatments in the reservoirs with natural fractures create complex fracture networks. Complex behavior of fluid flow in extremely tight porous media and presence of hydraulically fractured long horizontal wells in tight oil reservoirs imposes different set of challenges for performance prediction.
This paper presents a comprehensive hybrid grid model and performance analysis workflow to study the impact of reservoir and hydraulic fracturing parameters on production performance of tight oil reservoir. In the coarse model, large-scale fractures are treated explicit like conventional discrete fracture models, while relatively small-scale fractures are upscaled into dual porosity grids by global upscaling procedures. We performed history matching with field production data in the ChangQing oilfield. Based on the history matching results, fracture half-length and fracture conductivity were quantified and the present model is validated against production data.
The effect of fracture density, complexity of the fracture network, and permeability of the rock matrix on well productivity and tight oil recovery is studied in this paper. Subsequently, we performed optimization of multiple horizontal wells placement in a spacing unit with purpose of maximizing the reserve utilization. Finally, the optimal facture length of wells was determined. The proposed method provides a useful tool for diagnosing natural fractures, quantifying stimulated-reservoir volume, and assessing reliability of future performance predictions.
