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the picture shows "hai kui no. 1" and "hai ji no. 2". photo by li haowei (people's vision)

"3, 2, 1, start the oil well!" on september 19, in the waters of the pearl river mouth basin, as the production command was issued, the underwater robot slowly opened the oil tree more than 300 meters deep, and crude oil gushed out. my country's first deepwater oil field secondary development project was put into production.

on this day, two "energy heavyweights" - asia's first cylindrical floating production storage and offloading unit (fpso) "anemone no. 1" and asia's first deepwater jacket platform "haiji no. 2" were put into operation, marking that my country's design, construction and installation capabilities of all types of deepwater oil and gas equipment have reached world-class levels.

after nearly four years, what new model was adopted in the project development? what new technologies and methods were applied in the construction? the reporter conducted an interview.

innovative model reduces development costs by nearly 1 billion yuan

internationally, deepwater oil and gas is usually defined as oil and gas resources in waters deeper than 300 meters. my country's first deepwater oilfield secondary development project consists of two oilfields, liuhua 11-1 and liuhua 4-1, with an average water depth of about 305 meters and a peak daily oil production of about 2,700 tons.

the liuhua 11-1 oilfield, which was completed and put into production in 1996, is a deepwater reef limestone oilfield that is extremely difficult to develop. after years of exploitation, the recovery rate is less than 20%. "now, the exploitation life of the liuhua oilfield has been extended by 30 years, and it has ushered in a second development opportunity." said yuan wei, deputy general manager of cnooc shenzhen branch. the old oilfield has been rejuvenated, and how to choose an economical and efficient development model is a difficult problem. through demonstration and comparison, the project team proposed the "deepwater jacket platform + cylindrical fpso" development model. what is new about this model?

let's first look at the "haiji no. 2", which moves the production system from underwater to the platform, and is mainly responsible for crude oil extraction and pretreatment. the total height of the "haiji no. 2" is 428 meters, and the total weight exceeds 50,000 tons. the jacket is equivalent to the "foundation", supporting more than 300 sets of equipment on the offshore oil and gas platform. compared with the previous all-underwater production system model, it can greatly reduce engineering construction and production costs.

let's look at the "anemone no. 1" 2.5 kilometers away. it has changed from a traditional ship-type structure to a cylindrical structure. it is responsible for processing the crude oil mined by the "haiji no. 2" into qualified crude oil for storage and export. the total weight of the "anemone no. 1" is about 37,000 tons, with a maximum oil storage capacity of 60,000 tons, and can process 5,600 tons of crude oil per day. compared with conventional ship-type structures, cylindrical fpsos are less sensitive to wind, waves and currents in all directions and can better adapt to deep-water environments; at the same time, they are smaller in size, more compact in space, use less steel, and significantly improve oil storage efficiency.

the last is the underwater pipe and cable connecting the "haijit-2" and "haikui-1". the total length of the 7 pipes and cables is 69 kilometers, and they play an important role in the transmission of oil and gas resources and optoelectronic signals.

"the creation of the 'deepwater jacket platform + cylindrical fpso' model has helped reduce project development costs by nearly 1 billion yuan, making the development of a large number of potential deepwater marginal oil fields possible," said wang huoping, deputy general manager of the liuhua oilfield development project of cnooc shenzhen branch.

“energy heavy equipment” is more stable, more sophisticated and more intelligent

"anemone no. 1" and "haiji no. 2" set many firsts, and there was no experience to draw on in china. in addition, the wind direction in the sea area where they were located was changeable and internal waves and currents occurred frequently, which put higher demands on construction technology and processes.

with the "dinghai shenzhen" fixed in place, the roots are more secure.

wang deyang, an engineer of liuhua oilfield development project of cnooc shenzhen branch, told reporters that there are four corners at the bottom of the "haiji no. 2" jacket, and each corner has four skirt pile sleeves with a diameter of nearly 3 meters, a total of 16, which look like the thrusters at the bottom of a rocket. with the cooperation of pile hammers and underwater robots, 16 steel piles with a length of about 170 meters and a diameter of about 2.7 meters, like "sea-stabilizing magic needles", are inserted into the skirt pile sleeves and deeply nailed into the seabed, and then the gaps are filled with special cement.

for the "anemone no. 1", the project team adopted a multi-point mooring method for installation. the 12 anchor legs were divided into 3 groups, with 4 legs in each group, providing stable mooring force from the northeast, southeast and northwest directions.

supported by innovative technology, the construction is more refined.

how sophisticated are the construction requirements? shu wei, general contractor of liuhua oilfield, listed several sets of data: "anemone no. 1" is composed of more than 600,000 parts, with a hull of more than 90 meters in diameter, integrating more than 700 key equipment, and the total length of the cable can circle beijing's fifth ring road more than five times. the height between the hull and the upper module is less than 6 meters, and more than 20,000 meters of pipelines need to be arranged; the hull is composed of more than 120 special-shaped sections, and the main size tolerance must be controlled within 25 mm...

empowered by the twin platform, it runs more intelligently.

rooted in more than 300 meters of deep water, the "haiji no. 2" jacket cannot be seen or touched. how to monitor and operate it? wang huoping said that the installation of 380 sets of monitoring sensors, seabed full-profile flow observation platforms and other systems allows the land command center more than 240 kilometers away to simulate and generate a digital twin jacket, realize real-time monitoring of environmental data such as wind, waves and currents and the status of the jacket, and improve the level of digital operation and maintenance.

"anemone no. 1" is the world's first cylindrical fpso that integrates nearly 10 digital and intelligent systems such as integrated ocean monitoring, hull motion and mooring digital twins, and can achieve remote control production during typhoons. not long ago, "anemone no. 1" and "haiji no. 2" achieved mobile 5g network communication coverage, providing a stronger guarantee for the digital and intelligent development of deepwater oil and gas fields.

offshore oil and gas exploration and development accelerates breakthroughs

in the past 10 years, 70% to 80% of the world's new oil and gas fields have been discovered in the ocean, of which nearly 2/3 are concentrated in deepwater areas. my country's deepwater oil and gas exploration and development is still in its early stages, and there is a broad prospect for increasing reserves and production.

cnooc, together with more than 40 advanced manufacturing companies in china, has overcome a series of technical difficulties and promoted the coordinated development of the industrial chain in the construction of the secondary development projects of liuhua 11-1 and liuhua 4-1 oilfields.

complex sea conditions such as high salt, high humidity, wind, waves and currents challenge the steel strength of the "haiji no. 2" jacket. if traditional steel is used, the weight of the jacket when launched will reach about 42,000 tons, exceeding the maximum carrying capacity of construction sites, construction ships and other resources at home and abroad at that time. fu dianfu, deputy director of the engineering research and design institute of cnooc research institute, introduced that they jointly conducted trial production with major domestic steel mills, independently developed a new type of ultra-high-strength steel thick plate, and mastered the key technology of lightweight design, which reduced the weight of the jacket by about 5,000 tons and saved more than 100 million yuan in materials and ship modification costs.

the commissioning of the first deepwater oilfield secondary development project is a microcosm of the rapid progress of my country's offshore oil and gas exploration and development and engineering technology equipment. in the past 10 years, the "deep sea no. 1" energy station has promoted the offshore oil and gas exploration and development capabilities to 1,500 meters ultra-deep water; the independently developed "xuanji" system has broken the foreign monopoly and accurately controlled the drill bit thousands of meters underground to "aim" at the oil layer and "smell" the oil; deepwater and shallowwater underwater oil trees and marine tow cables, seabed node seismic exploration and acquisition equipment have all been domestically developed and independently developed...

data released by the national energy administration showed that my country's marine crude oil production exceeded 62 million tons in 2023, and the increase has accounted for more than 60% of the national crude oil increase for four consecutive years, helping to further consolidate the basic foundation of long-term stable production of 200 million tons of domestic crude oil.

people's daily (page 02, september 20, 2024)