Openhole (OH) multistage (MS) technologies can maximize reservoir contact and productivity by optimizing the distribution of acid across the formation matrix. Successful completion of these reservoirs can be challenging. This paper discusses the recommended practice for optimizing OH fracture stages and cluster placement distribution within heterogeneous unconventional oil carbonate reservoirs based on formation, completion properties, and reservoir fluid distribution.
Completion technology is based on distributing intelligent packers along the lateral section to develop the MS fracturing stages. Intelligent packer displacement influences fracture effectiveness and conductivity. Typical packer placement can undermine formation potential and productivity results. Packers and their ports are placed based on the formation's petrophysical and mechanical properties to increase the cumulative production in a shorter timeframe and help improve recovery. The workflow followed was based on analysis of the reservoir properties (porosity and permeability). These were later integrated with the measured rock mechanical properties. The developed integrated model was used to divide the rock into segments that share similar properties.
The use of an advanced azimuthal sonic with a high signal-to-noise ratio and wider frequency response helped improve the accuracy in assessing formation mechanical properties. Additionally, conventional logs, when combined with formation mobility measurements, help calibrate the permeability model and classify the formation into distinctive clusters. These clusters are then grouped according to their mechanical and brittleness properties to form a separate unit with a selected fracture port to help ensure the necessary fracture length. The developed method provides an opportunity to determine the necessary fracture stages and reduce the risks of over or underplacement. It also improves stage integrity, helps ensure better distribution of the acid across the formation matrix, and provides effective propagation of the fracture network.
The applied procedure follows an innovative workflow to optimize the fracture stage and cluster placement distribution across the reservoir using a new combination of advanced and conventional data acquisition and interpretation. The discussed case study demonstrates the benefits of engineered fracturing stage placement compared to a geometric displacement.