Project Full Name：Research and Application of Shale Gas Horizontal Well" Casing In Casing " Refracturing Technology 

Company：Sinopec Chongqing Fuling Shale Gas Exploration and Development Co., LTD / Sinopec Jianghan Oil Field Co., LTD / Sinopec Jianghan Petroleum Engineering Co., LTD. Downhole Testing Company

Awarded：Stimulation & EOR Technology

Standeard:  International Advanced Level

Projec Number：ECF-2022-SEP-1008

Principal Accomplishers： Liu Yaowen, Yuan Fayong, Li Yuanzhao, Mingyue, Zhang Chi, Dou Ruijie ,Shen Jincai, Wang Dajiang ,Liu Lizhi

Step diagram

JY4HF production curve

Key Innovation Points：

1. Establish the well selection method of shale gas refracturing;

   
   

2. Form a refracturing technology suitable for shale gas horizontal well " casing in casing " refracturing technology;

   
   

3. Innovative research and development of supporting tools and material systems suitable forshale gas horizontal well" casing in casing " refracturing technology.

Main Application and Technical Principal： 

As an unconventional energy source, shale gas has the characteristics of low porosity and low permeability, which requires large-scale hydraulic fracturing to form an artificial fracture network to provide seepage channels for production. However, after fracturing, there are generally problems of rapid production decline rate and short stable production period. Refracturing technology is an important technical measure for increasing and stabilizing production in the middle and late stages of shale gas field development. "Casing in casing " refracturing technology is aimed at the phenomenon of insufficient production of reserves around the wellbore of a shale gas well. By running a small-sized casing into the original wellbore for cementing, mechanically sealing the perforation holes of the initial fracturing, a new channel is formed in the wellbore, within the wellbore to form new channels, and initial reform steps again the same segmental perforation fracturing. This technology can completely seal the original perforation, precisely control the fracturing position and the direction of the fracturing fluid, reduce the leak off rate, and improve the single-well recovery rate by improving the pertinence of refracturing.