China's gas storage construction has achieved original technological breakthroughs

On March 15, with the closure of gas storage valves, this year's heating season passed
smoothly.

Among them, the technological breakthrough in the construction of natural gas storage reservoirs in China is
indispensable.

Zheng Dewen, chief expert of the China Petroleum Exploration and Development Research Institute, introduced that the underground gas storage reservoir is a key part of the production, supply, storage and marketing system of the upper, middle and lower reaches of natural gas, and its role in ensuring national energy security and national economy and people's livelihood is crucial
.

In 2017, there was a tight supply of natural gas in some parts of northern China, which exposed some deficiencies
in China's natural gas production, supply, reserves, sales and other links.
The National Development and Reform Commission and the National Energy Administration jointly issued the Opinions on Accelerating the Construction of Gas Storage Facilities and Improving the Market Mechanism for Gas Storage and Peak Regulation Auxiliary Services, requiring gas supply enterprises to have a gas storage capacity
of not less than 10% of the annual sales volume of the contract.

"The momentum of natural gas development is strong, and the lack of gas storage capacity is still a bottleneck
restricting the sustainable and high-quality development of China's natural gas business.
" Zheng Dewen said
.

At the same time, complex geological conditions make the construction of gas storage in China face a series of severe challenges
.
"After more than 100 years of development, foreign gas storage reservoirs have diverse types and complete systems, providing valuable reference experience
for China.
" Zheng Dewen said that the construction and operation technology of gas storage reservoirs in foreign countries, which are mainly shallow simple structures and medium and high permeability reservoirs, is difficult to solve the key problems
of complex deep gas storage reservoirs in China.

The team, led by Professor Ma Xinhua of the China Petroleum Exploration and Development Research Institute, launched a research on this difficult problem
.
In the face of the world-class problem of building reservoirs in China's complex faults and low-permeability and near-depleted gas reservoirs, after nearly 30 years of scientific and technological research, the team has formed four characteristic comprehensive technologies
for building libraries.
First, it has innovated and formed key theories and methods for building reservoirs such as dynamic sealing of gas storage reservoirs of complex fault-block gas reservoirs, high-speed injection and production seepage flow, and created a world record for
the construction of reservoirs such as the deepest burial, the highest operating pressure and the largest pressure difference at the bottom of the well.
Second, the technologies of ultra-low pressure formation drilling and leakage plugging, alternating load anti-fracture cementing, and alternating working conditions injection and production pipe column design are basically mature, which supports the large-scale construction
of domestic gas reservoir gas storage reservoirs.
The third is to develop high-pressure and large-displacement reciprocating gas injection compressor units to break the monopoly of imports
.
The fourth is to establish a safety control system for the whole life cycle, and develop safety testing equipment such as underground leakage detection and helium seal testing of injection pipe columns, and the performance has reached the level of
similar foreign products.

A number of technologies, equipment, products and software formed in this process have supported the construction of 24 gas storage depots
of PetroChina.

Zheng Dewen introduced that during the "14th Five-Year Plan" period, China has determined the overall plan to accelerate the construction of underground reservoirs, and the peak regulation capacity of new gas storage reservoirs of PetroChina according to demand exceeds 10 billion square meters, that is to say, it takes 5 years to complete the sum of the new peak regulation capacity in the first 20 years, with heavy responsibility and arduous
task.

PetroChina underground gas storage technology research to the new library construction needs and "card neck" technology to carry out a new round of research, in view of a series of scientific, technical, engineering and other issues, set up "complex gas storage geological sealing evaluation and storage capacity efficient utilization technology research" and "complex fault block high-quality gas storage construction" and other 5 demonstration projects, and strive to achieve new breakthroughs
in gas storage construction technology.

PetroChina's underground gas storage technology research team led the application for the "National Energy Underground Gas Storage R&D Center" is also in
full swing.

According to reports, after the approval of the establishment of the National Energy Underground Gas Storage R&D Center, it will focus on creating the source of original technology research and development of China's gas storage reservoirs, and play an active role
in ensuring the safe and stable supply of domestic natural gas, rapidly promoting the company's gas storage capacity building with scientific and technological support, solving the company's major production problems in complex gas storage reservoirs, and realizing resource integration to enhance scientific and technological innovation capabilities.
"It will make important contributions
to the realization of the national goal of '55-60 billion square meters of intensive gas storage capacity in 2025, 60-70 billion square meters by 2030, and 70-80 billion square meters by 2035'.
" Zheng Dewen said
.