Diagnostic Pumping Tests To Optimize Fracturing Designs in the Harsh Environment of Western Siberia

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractHydraulic proppant fracturing continues to rapidly evolve in western Siberia/Russia and is seen as the most important and effective means to improve oil production from existing, as well as, newly drilled wells.Fracture treatments in Russia were traditionally small, conservative treatments with small-sized proppants and inefficient fracturing fluids. They were designed with a onesize-fits-all approach to bypass near-wellbore damage rather than provide sustained and optimum productivity. Results were acceptable for the economic models existing at that time. However, the competitive environment, production targets, and financial goals of oil-producing companies today require a change in approach.Optimization of hydraulic-fracturing treatments soon became a necessity and resulted in a design methodology aimed at improving the production performance rather than simple modification of pumping schedules. Designing for performance required a change in tactics and an optimization mentality to achieve step-change results. 1,2 Production analysis suggested radical changes in fluids, breakers, job sizes, types, and tonnage of proppant, etc. In this paper, we discuss and compare the evolution of the stimulation practices and implementation of technology that matched performance to fracture design. We describe some of the steps and practical standards implemented to improve the performance of hydraulically induced fractures.In particular, we discuss the critical importance of the minifrac diagnostics used intensively and extensively as a powerful diagnostic procedure. The diagnostic procedure became the most useful and practical tool for fracture placement and successful execution of larger fracture treatment designs with larger proppant sizes, perforating strategy, redesign of fracturing treatments on location, and continuous improvement of treatment designs and placement. The paper will examine the different pumping diagnostics performed in western Siberia and some of the reoccurring results observed. It also evaluates the consistency and specific problems encountered working around the traditional completion and operational practices in West Siberia, and best practices for performing a minifrac during extreme cold.