Natural Gas Industry B (Oct 2020)
Connotations of scientific development of giant gas fields in China
Abstract
A giant gas field refers to a gas field with proved geological reserves of natural gas more than 30 billion cubic meters, peak annual output of natural gas more than 1 billion cubic meters, and a certain plateau period. It is an important foundation for the rapid growth of China's natural gas reserves and production and its long-term stable development in the future. And it is also the key to ensure the security of gas supply. By systematically analyzing the development practice of more than 260 gas fields at home and abroad and dissecting and simulating typical gas fields, this paper comprehensively studied the connotation, core technology and whole life cycle index system on the scientific development of giant gas fields. It is indicated that the scientific development connotation of giant gas fields consists of the following parts. First, the natural gas development concept with “water identification, control and treatment” as the technical system is put forward. That is to carry out “water-control development” in conventional gas fields and hydraulic fracturing development in unconventional gas fields. A reasonable gas production rate should be set according to the types and characteristics of gas reservoirs. Second, economic and social benefits of gas field development should be evaluated comprehensively to ensure its long-term stable production. Third, the suitable production stabilization mode shall be adopted according to the production characteristics of gas wells and the development characteristics of reservoirs. Fourth, the recoverable reserves of a gas field, the development laws of formation water and artificial water flooding, the ultimate recovery technological countermeasures of the gas field, the cost-effective stable period of the gas field should be determined based on the fine description of conventional and unconventional gas reservoirs in different stages, the development characteristics of gas reservoirs and the monitoring results of production performance. The core technologies in the scientific development of giant gas fields include large-scale optimization technology, scientific well arrangement technology, balanced production technology and deep potential tapping technology. Based on this, several parameters are selected comprehensively as the key indexes for the scientific development of giant gas fields, such as production rate, pressure drop, degree of reserves recovery and output per unit pressure drop, and the whole life cycle index systems for four types of gas reservoirs are established, i.e., high-pressure gas reservoirs, low-permeability and tight gas reservoirs, fractured–porous reservoirs, and shale gas reservoirs. In conclusion, the research results enrich and improve the theories of natural gas development geology and are conducive to guiding the scientific development of different-type giant gas fields, thus further promoting the rapid development of natural gas industry in China.
