Experimental Study, Characterization and Application of Starch-Graft-Acrylamide Gel for Plugging

  • Zhen LI The Branch of Key Laboratory of CNPC for Oil and Gas Production, College of Petroleum Engineering, Yangtze University, Wuhan, China, 430100
  • Li CHENG The Branch of Key Laboratory of CNPC for Oil and Gas Production, College of Petroleum Engineering, Yangtze University, Wuhan, China, 430100; Lost Circulation Control Division, Oil and Gas Drilling Technology National Engineering Laboratory, Wuhan, China, 430100.
  • Ruiquan LIAO
  • Manlai ZHANG
  • Kangwei ZHANG
  • Long YUAN
  • Gang LIU
Keywords: modified starch gel, plug, snubbing service, microstructure

Abstract

During underbalance drilling, completion and workover wells, plugging channeling, blocking preformation and plugging formation water are inevitable problems. Gel is one of the most effective and convenient method to solve the problem. In this study, modified starch gel is synthesized, investigated experimentally and improved for efficient oil and gas field applications. The gel slurry is composed of starch (3.6 wt.%), initiator (0.02 wt.%), acrylamide (14.4 wt.%), cross-linking agent (4.7 wt.%), all of the components are mixed together with water at pH 1011 which viscosity is as low as 3582 mPa.s and desired to form gel. Here the effects of the components, reaction temperature and pH on gelation time and gel viscosity are systematically investigated, and the results showed that the gelation can be controlled in a wide range 30120 min efficiently by pH and initiator. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) are employed to study the molecular structure and microstructure of the gel, respectively. A compact three-dimensional network structure was formed in the gel, which contribute to a good adhesion. The gel has been successfully used in shale gas field which provides a reference for sealing other similar high formation pressure under unbalanced workover treatment.

DOI: http://dx.doi.org/10.5755/j01.ms.24.4.18565

Published
2018-09-04
Section
POLYMERS AND COMPOSITES