Zhangxing Chen

Fractured Reservoir Modeling: Effects of Hydraulic Fracture Geometries in Tight Oil Reservoirs

Tight oil production is emerging as an important new source of energy supply and has reversed a decline in U.S. crude oil production and Western Canadian light oil production. At present, combination of the multistage hydraulic fracturing and horizontal wells has become a widely used technology in stimulating tight oil reservoirs. However, the ideal planar fractures used in the reservoir simulation are excessively simplified. Effects of some key fracture properties, such as facture geometry distributions and permeability change, are usually not taken into consideration during the simulation. Over simplified fractures in the reservoir model may fail to represent the complex fractures in reality, leading to significant errors in forecasting the reservoir performance. In this paper, we examined the different fracture geometry distributions and further discussed the effects of geometry distribution on well productions. All fracture geometry scenarios are confined by the microseismic mapping data. To make the result more reliable and relevant, a geo-model was first constructed for a tight oil block in Willesden Green oil field, AB, Canada. The simulation model was then generated based on the geo-model and history-matched. A horizontal well was drilled in the simulation model and different fracture geometry scenarios were analyzed. Results indicate that the simulation results of simple planar fractures overestimate the oil rate and lead to relatively higher oil recoveries. In addition, the effect of hydraulic fracture geometries under the higher fracture conductivity is more significant compared to those under lower fracture conductivity.

An integrated geology and reservoir engineering approach for modelling of a giant fractured basement reservoir

A great portion of the worlds oil reserves is contained in naturally fractured reservoirs (NFRs). As the conventional oil and gas reservoirs have become significantly depleted whereas energy demand sharply increases, the NFRs play an important role in oil exploration and make a large contribution toward oil and gas production worldwide. This paper aims to introduce a historical case study of a successful development plan for a giant fractured granite basement reservoir with a unique geological characterisation. A better geological understanding about the complexity of such a naturally fractured basement reservoir is provided within a simulation strategy in order to optimise successfully its oil exploitation. With our rich experiences in exploration and production of hydrocarbons in fractured basement granite rock for more than 20 years, it is a valuable case study for both current and future development planning of basement reservoirs elsewhere in the world. [Received February 5, 2013; Accepted November 25, 2013].