Technical Assessments of Horizontal Drilling with Multistage Fracturing to Increase Production from Hassi Tarfa Field, Algeria

Abstract

Unconventional resources have become the core business of many petroleum companies to meet the increasing demand for energy. Several technologies and methods have been developed and deployed to unlock the potential of tight and ultra-tight formations. Hassi Tarfa (HTF) oil field is a thin and tight sandstone reservoir in Algeria, with an average permeability of less than 0.5 mD. However, all drilled wells in this field are vertical. Hydraulic Fracturing (HF) is the prime stimulation technique that is applied to increase oil recovery in unconventional reservoirs. Although the well production tremendously increases after fracking operation, it does not sustain for longer period of time, which keeps the estimated ultimate recovery (EUR) to be relatively low. In this study, a reservoir model was built and history matched, in order to consider three scenarios to optimize the horizontal lateral length in the HTF field. Then, multistage HF design was simulated using advanced 3D finite element software and exported to the model to estimate the potential increase of EUR. Sensitivities on number of HF stages, fluid volumes, and proppant were conducted to identify the optimal number of HF stages. The results of this study showed that, employing multistage hydraulic fracturing along horizontal drilling can significantly improve the oil recovery in HTF formation. Fracture length and the number of stages showed to be important design parameters. This study also identified the optimal range of operational parameters such as pumping schedule, proppant mass and perforation interval which are crucial to the cost reduction and operation efficiency.