Experience and Optimization of Essential Multistage Fracturing Technology with Coiled Tubing at the Well for the Vinogradova Oilfield

Abstract

In the article presented 2 years of experience gained during multi-stage hydraulic fracturing (MSF) on 17 wells, by means of coiled tubing (CT) without lifting it to the surface, performed in years 2017 – 2018 on Vinogradova oilfield, KhMAO, Russia. In 2017 it was successfully implemented innovative technology, where fracturing operations are combined with coiled tubing (CT) operations and are run together with CT inside the well. Current method is based on operating reusable fracturing ports, where opening and closing is carried out using coiled tubing with subsequent performace of MSF along the CT/Tubing annulus. During these jobs, considerable experience was gained, the technologies were optimized and raised issues solved, including excessive abrasive wear of the coiled tubing pipe, leaks, etc. Vinogradova oilfield is a unique oil-saturated low-permeable reservoir with a small effective thickness, characterized by considerable stratification and gas-saturated porous layers. MSF technology demonstrated high efficiency and proved its reliability. Starting from February 2017 till June 2018 it was 17 wells accomplished, where 246 fracturings were carried out. All the wells were successfully commissioned. The implementation of innovative approaches to multi-stage hydraulic fracturing while coiled tubing remains in the well, resulted in 2-fold work time reduction, while the amount of frac ports doubled per well. The time frame of CT work between fracturing stages was minimized from 4 to 1.5 hours. During the job on one of the wells, it was encountered a leak in the completion (liner) in the shoe area, in order to continue MSF job, the isolation packer was run and temporary installed, which allowed to accomplish the operation. The performance of MSF technology without lifting coiled tubing to the surface proved its efficiency and economic feasibility, becoming more and more popular among operating companies, it has great potential for future implementation both in Russia and in the rest of the world. The area of distribution and application of MSF using CT is growing every year, the most relevant technology found in oil fringe with a gas cap or bottom water. The accumulated experience in this project creates the basis for the wide introduction and application of technology on other projects