Gas injection processes

London, Institute of Materials, 2001, Paper 28, pp5,012 DEVELOPMENT OF AN HDPE COMPOUND FOR INSULATION OF COMMUNICATION CABLES BY THE GAS INJECTION PROCESS... 

This paper discusses the latest advances in manufacturing Community Antenna Television (CATV) cables via the gas injection process. Developments in polymer technology are discussed which have led to the production, by gas injection, of highly expanded, ultra low dielectric loss PE cable insulation for CATV and data transmission 3 refs. 

Figure 1.2 shows the basic block diagram for the acid-gas injection process, including a block for the natural gas sweetening unit. For CCS, the sweetening block is replaced by a carbon capture block, but the rest of the process is unchanged. The four main components of the injection scheme are 1. compression, 2. pipeline, 3. injection well, and 4. reservoir. Each of these will be discussed in some detail in this book. 

When combined with acid gas mixtures, ethane and carbon dioxide exhibit azeotropy, as do propane and hydrogen sulfide. Although the azeotrope does not have a significant effect on the acid gas injection process, it tells a tale about the phase equilibrium in these mixtures. 

Ng, H.-J., J.J. Carroll, and J. Maddocks. 1999. Impact of thermophysical properties research on acid gas injection process design. 78th Annual GPA Conv., Nashville, TN. 

Figure 7.68 A gas-injected part. Such a complex shape requires three-dimensional analysis to accurately simulate the gas-injection process.

Because it is often not feasible to change the properties of the displaced fluid when it is oil or the permeabilities of the rock to the displaced fluids, most mobility-control processes of current interest involve addition of chemicals to the injected fluid. These chemicals increase the apparent viscosity of the injected fluid and/or reduce the effective permeability of rock to the injected fluid. The chemicals used are primarily polymers when the injected fluid is water and surfactants that form foams when the injected fluid is a gas. In some cases, mobility control is attained in gas-injection processes by the injection of alternate slugs of gas and water. 

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