Pinpoint multistage fracturing of tight gas sands- An integrated model with constraints

As the demand for gas increases worldwide, tight, deep and multilayered unconventional gas sands are becoming the target for development. For such reservoir the conventional approach of simple fracturing the formation to hydraulically stimulate the well is inadequate. Continuous progress in hydraulic fracturing technology results in pinpoint fracturing, which allows multiple precisely targeted sands to be stimulated. Recently, this technique has been used in the developmet of tight gas sands. However, the systematic design methods for fracture treatment parameters with constraints are not well presented in the literature. Even the most currently available commercial software lack proper optimization tools in them and they do not take into consideration several key parameters and realistic constraints in them. An integrated but constrained model to design pinpoint multistage fracturing treatment has been developed to maximize gas production from layered tight sands. Model couples both the industry experience and design parameters based on hydraulic fracture mechanics. This integrates reservoir in-situ parameters, fracture geometry, fracture treatment design, realistic design constraints, and production and economic models. The integrated model has been successfully applied to a hypothetical deeper and layered tight gas sands to demonstrate its merits. A parametric study is also conducted to compare between the conventional single-stage and pinpoint multi-stage hydraulic fracturing with their basic design concepts and post-fracture benefits. It is evident that the productivity increase is about 20-fold higher in pinpoint multistage fracturing compared to 6-fold for blanket fracturing. Insightful parametric sensitivity analyses are also presented. This model could also be used to study the potential of the deep UAE tight gas sands.