Abstract
As the demand for gas increases worldwide, tight and deep unconventional gas sands are becoming the target for development. Continuous progress in hydraulic fracturing technology has resulted in multistage transverse fracturing of horizontal well in tight gas sands. However, for such reservoirs the conventional approach of simply fracturing the formation to stimulate the horizontal well is inadequate. This is because most currently available commercial software lack proper optimization tools in them and they do not take into consideration several key parameters and realistic constraints. Even the systematic design methods for fracture treatment parameters with constraints are not well presented in the literature. Although larger the number of transverse fractures higher the productivity, there are optimal number of fractures and optimum treatment parameters when real field constraints and economic aspects are considered. A new integrated but constrained model to optimize multistage transverse fractures has been developed to maximize gas production and net present value with minimum treatment cost. Model couples both the industry experience and unified fracturing design parameters based on hydraulic fracture mechanics. Unified fracturing design defines the optimal compromise between the fracture width and fracture length for a given mass of proppant. Model integrates unified fracture geometry, reservoir in-situ parameters, treatment parameters controllable at every stage, realistic design constraints, and production and economic modules. The integrated model has been successfully applied to a hypothetical deeper and tight gas sands to demonstrate its merits. A simple and accurate analytical approach has been used for evaluating and optimizing the productivity. This model could also be used to study the potential of the deep UAE offshore tight gas sands, which is yet to be developed.
