Optimization of Horizontal Well Fracturing Design Using Mechanical Specific Energy (MSE)

Abstract

AbstractMultiple-stage and multiple-clusters of horizontal well fracturing requires not only an optimized operation design, but also an efficient fracture stage/cluster design. Traditional geometrical stage design has disadvantages of little to none concern for reservoir heterogeneity along the lateral. In contrast, a new application concept of Mechanical Specific Energy (MSE), has been deployed by many operators in the North American shale basins and used to improve engineered completion designs. This paper presented a way to integrate MSE with rock mechanic parameters, and other log-based parameters to improve fracture designs.MSE originally states the amount of energy and work done to cut a volume of rock. It is the response of drill bit when interacting with rock, hence has direct correlation to the hardness/strength of rock. In reality however, due to the energy loss factors, the input energy does not transfer to the effective energy to break the rock. This study uses rock mechanic parameter such as Unconfined Compressive Strength (UCS), Brittleness Index (BI), and other log-based parameters such as GR ray (GR), to build a correlation with MSE.The implementation of this technique was conducted through a case study for a very low perm sandstone reservoir at northern coast of Bohai Bay in China. A data analysis of fracturing design and production from a shale play in the USA also presented. With multivariable analysis techniques, a rock-MSE-microfacies concept was developed to overcome any possible MSE from abnormal data during drilling so that with corrected MSE-C to present the Rock-MSE-microfacies. With and without the extended MSE methodology applied, the clusters placement would be very different, and more uniform fractures and better the cluster efficiency has been achieved with MSE strategy.As the result of this project, an optimized process incorporating multiple tools for a final multi-stage and multi-cluster fracturing design was developed. The design with optimized stage and cluster was compared with other scenarios, from fracture geometry to the10 years production rate and cumulative production of the horizontal well. This study demonstrated that drilling data can be effectively used for fracturing design to produce superior results in production. In addition, the study assisted to locate engineering sweet spot for fracturing and guide the determination of perforation locations for improving fracturing design of horizontal wells.KeywordsMSERock-MSE-microfacies (MSE-C)Perforation spotSophisticated frac design