Channel Fracturing Extension to Low-Temperature Formations. Field Case Studies in Russia.

Abstract

Channel fracturing technology has been a key enabler to unlocking hydrocarbon production from low-permeability formations in Russia for 10 years, by minimizing treatment costs and improving operational efficiency. However, an intrinsic limitation existed for candidate selection because the technique requires post-job dissolution of the fiber that is a principal component of the success of achieving efficient channel fracturing behavior. This set a lower temperature limitation of 60°C, such that formations with temperatures below this value were not recognized as potential candidates. This project was aimed at eliminating the temperature limitation and thereby enhancing the potential candidate pool for application. The channel fracturing technique creates infinite-conductivity channels within a fracture, using a proppant-pulsing technique delivered by the surface equipment. Proppant structures are consolidated and transported along the fracture by means of fibrous material, which then degrades in the channels and proppant pillars within days after the treatment, conventionally because of the high formation temperature. Expanding hydraulic fracturing into new low-temperature oil provinces such as Eastern Siberia and the Turonian formation in the Yamal region called for adjustment in the channel fracturing technique. Specifically, surface equipment was used in a modified mode to alter the pumping schedule of the fiber additive to add fiber in pulses that are synchronized with proppant pulses. The new channel fracturing methodology was designed and tested under laboratory conditions initially and then subsequently applied in several low-temperature (20 to 30°C) oil and gas fields/wells in Russia. The first campaign yielded positive results. New software and equipment adjustments allowed for precise and accurate synchronization that resulted in fiber-free channels. The first productivity results also illustrated the potential of the technology to match or exceed the planned hydrocarbon production. The main advantages of the channel fracturing technique remained unchanged—improved barrels/dollar ratio by up to 10% compared with conventional methods and fracturing cycle operational efficiency reduction of up to 25% as compared with standard techniques. Thus, the temperature limitation was removed, leaving one major criterion for channel fracturing applicability: rock competency to hold channels open and stable throughout the life of the fracture. The study breaks new ground in the stimulation of low-temperature formations by extending the channel fracturing technique, well-recognized in the traditional basins of Russia. The project includes laboratory testing and real field examples from two regions of Russia—the first campaigns.