After more than 20 years of vigorous development, China Offshore Oil Company has become one of the key facilities for offshore oil field development. At present, 1 1 FPSO is in service, and another two FPSOs are under construction. China has become one of the few countries in the world that widely use FPSOs. 1 1 FPSO is distributed in Bohai Sea and South China Sea, and the water depth of the operating sea area varies from 20 to 330 m; The deadweight tonnage of FPSO ranges from 50,000 tons to 250,000 tons, and the total deadweight tonnage reaches 140× 104t. According to the environmental requirements of different sea areas, FPSO has three types: anti-icing, shallow draught and typhoon prevention. According to the use requirements of different oil fields, FPSO adopts the scheme of new construction, renovation and lease. The design life of the existing new FPSO is more than 20 ~ 30 years, which can be maintained during 20 ~ 30 years of offshore operation and can realize long-term continuous safety production.
Since the reform and opening up in 1980s, China Offshore Oil Corporation has built a 50,000-ton FPSO for Bohai BZ28- 1 Oilfield at 1987 (Figure 13- 1). Build "Bohai Evergreen" FPSO；; Bohai BZ34 Oilfield; In Nanhai W 10-3 Oilfield, an old tanker of180,000 tons was converted into Nanhai Hope FPSO, which was retired in 1998. The 250,000-ton FPSO Nanhai Discovery was rebuilt for Huizhou Oilfield Group. In the mid-1990s, five other FPSO were put into production in the Bohai Sea and the South China Sea, namely Pearl of the Bohai Sea (figure 13-2), Blooming in the South China Sea, Mining in the South China Sea (figure 13-3) and Victory in the South China Sea (figure13) Used for self-operated oilfield development. It has the function of operating in ice area and the design life reaches 20 years. The design and construction of this FPSO won the National Science and Technology Progress Award.
Starting from 1999, China Offshore Oil independently planned and designed a high-standard16000t FPSO and two15000t FPSOs built by domestic shipyards, namely Bohai Century (Figure 13-5), Nanhai Endeavour and Offshore Oil 65438. These three FPSOs are all used in the development of Sino-foreign cooperative oilfields, which are highly praised by oilfield partners and create a new milestone for FPSO.
Over the past 20 years, China Offshore Oil Corporation has gone through the process from planning and designing FPSO abroad to designing and building it completely at home. China Offshore Oil Corporation has accumulated long-term practical experience in the planning, design, construction and operation of FPSO, and can choose the scheme of building, rebuilding and renting FPSO according to the use requirements and economic benefits of different oilfield development. At present, FPSO has become a new industry of CNOOC in China, and we will provide foreign companies with FPSO facilities developed in oil fields at reasonable prices, with safe, reliable and high-quality services. With the development of small and medium-sized oil fields and marginal oil fields, all kinds of new FPSO will appear in China CNOOC.
A, the classification of floating production system
From the development and application of offshore oil and gas fields, floating production systems can be divided into the following three basic types.
A. Oilfield development system: The purpose of oilfield development system is to economically exploit reservoir fluids until the point of economic loss, and its service life generally exceeds 5 years.
B. Early, experimental or early oilfield production system: The purpose of this system is to produce reservoir fluids and provide reliable production experience and data for predicting the long-term productivity and ultimate recovery rate of the reservoir. However, the original intention of this classification is not to produce before the reservoir is exhausted, and its service life generally ranges from 60 days to 2 years, usually not more than 5 years.
C. Drill pipe testing system and extended testing system for oil wells or reservoirs: The purpose of this system is to collect data about oil well productivity, media characteristics, reservoir production characteristics, reservoir size and power, production problems, reservoir continuity, oil well maintenance and short-term reservoir maintenance, and its service life is generally 65,438+020 days.
Second, the function of floating production oil storage device
The cabin below the main deck of the floating production oil storage device mainly stores the produced crude oil, and the production deck above the main deck is mainly equipped with production treatment facilities, public facilities and living modules.
1. Treatment of crude oil and production sewage
Above the main deck of the floating production oil storage device, the production deck shall be set according to the production process requirements. The production deck is equivalent to a land treatment plant. The production deck is equipped with indispensable equipment for oil and gas production and sewage treatment, such as heaters, separators, coolers, sewage deoiling devices, compressors, delivery pumps, safety venting devices and other supporting facilities required for production. Qualified crude oil is stored in the tank; The treated production sewage can be directly discharged into the sea or used as the water source for oil field injection; The separated natural gas is used as fuel for generators and heating boilers, or transported to land for customers.
2. Power supply and heating
Developing an oil field requires a lot of mechanical equipment. Without electricity and heat, it is impossible to maintain the normal operation of these equipment and production process. FPSO uses the waste gas separated in the production process as fuel to generate electricity and heat the boiler. The heat generated by the boiler is used to heat the production process. The generated electricity can not only be supplied to FPSO for production and lighting, but also be transmitted to various wellhead platforms through submarine cables to provide electricity for wellhead platforms. This can reduce the equipment and weight on the wellhead platform, simplify the layout of the wellhead platform, and save the engineering cost and operation cost.
3. Living base and production command center
In addition to production facilities, FPSO is also equipped with houses for production operators to live and rest. The large scale of FPSO provides favorable conditions for housing layout, and the housing capacity ranges from dozens to hundreds. In addition to the bedroom and dining room, the house is also equipped with a special meeting room, recreation room, office, newspaper room and central control room, which not only provides a spacious and comfortable living and rest environment for FPSO operators, but also monitors the operation of the whole production process, provides support and services for nearby platforms, and becomes a veritable production command center in the oilfield. As an independent module, the living quarters can be arranged at the bow or stern of FPSO. The helideck is set at the top of the housing module for shift and emergency.
4. Store qualified crude oil
Except ballast tank, fuel tank, fresh water tank, pump tank and some process tanks, most of the cabins below the main deck of FPSO are used to store qualified crude oil, and the oil storage capacity ranges from tens of thousands to hundreds of thousands of tons, which is equivalent to a large offshore oil depot. Compared with other all-sea development schemes that can only store 6.5438+00,000 ~ 20,000 tons, it has unique and obvious advantages. The design tonnage and crude oil storage capacity of FPSO depend on the water depth in the oilfield sea area and the productivity of the oilfield. Generally, it should be able to store the output of oil fields above 10d. Otherwise, the shuttle tanker needs to stop at the exit frequently, which is greatly affected by the climate.
Figure 13- 1 "Bohai Friendship" 52,000-ton FPSO
Figure 13-2 "Bohai Pearl" 58,000t FPSO
Figure 13-3 "South China Sea Development" 150000 FPSO
Figure 13-4 "Nanhai Shengli" 144000 FPSO
Figure 13-5 Bohai Century160,000-ton FPSO
Figure 13-6 "Offshore Oil11"150000 FPSO.
5. Export qualified crude oil
FPSO can also be used as an offshore oil terminal where shuttle tankers dock. Qualified crude oil is transported to the shuttle tankers for export sales through oil pumps, metering systems and oil hose. Shuttle tankers can dock side by side or in series with FPSO, which mode to choose depends on the environmental conditions and operational requirements of the oilfield. Side berthing has great restrictions on the tonnage and environmental conditions of shuttle tankers. Therefore, in ice-free sea areas, it is more flexible to use series berthing to transport oil. When transporting oil in series, it is necessary to equip several hundred meters long oil hose and some corresponding mechanical equipment.
Three. Characteristics of production system of floating production oil storage device
From the South China Sea with a water depth of several hundred meters to the Bohai Sea with a maximum water depth of more than 30 meters and sea ice in winter, China Offshore Oil Corporation widely uses FPSO to develop offshore oil fields, and the crude oil output produced by FPSO now accounts for more than half of the domestic crude oil output of China Offshore Oil Corporation, which fully shows that this development device has attractive characteristics and advantages.
1. has strong adaptability to water depth and environmental conditions.
This production system can be used in tens to hundreds of meters or even deeper places. In shallow water, it is more economical to adopt fixed structure, while in deep water, it is more flexible to adopt catenary mooring structure. Both the high latitude sea ice area in Bohai Sea and the stormy South China Sea hit by typhoons in summer have been successfully applied.
2. It has the effect of wind drift and the best stress condition.
Because the floating production and storage device is connected with the single-point mooring system through rotating parts, FPSO is basically in a free-floating state. Therefore, under the joint action of environmental forces such as wind, waves, currents and ice, FPSO can not only swing freely, but also rotate 360 degrees around a single point, making FPSO in the best stress state, with the smallest stress area and the most economical single-point structural design.
3. There is enough area and space.
Adding a production deck on the main deck of the floating oil storage device makes full use of the whole area and space of the floating oil storage device, which provides good conditions for storing crude oil, arranging production and processing facilities and public facilities, and housing for operators. In addition, it also serves as an offshore oil terminal where shuttle tankers moor and dock, making it a comprehensive offshore base integrating production, life, oil storage and oil transportation. The project cost is relatively low.
Be flexible
Floating production oil storage devices are usually connected to a point through some special parts, and can be easily detached from these connecting parts when necessary. When the anti-icing point in Bohai Suizhong 36- 1 oilfield experimental area encounters severe ice conditions, the planned release of FPSO can be completed within a few hours, and the FPSO can be towed to a safe place. According to the environmental conditions and production needs, FP-SO can also be designed to resist the worst environmental conditions once in a hundred years and can never get rid of them.
5. Reusable
Reusable is another major feature of floating production oil storage device. This feature is especially suitable for marginal oil fields with short development cycle. After the development of an oil field is completed, the production facilities can be reused after proper transformation and maintenance according to the requirements of the next oil field. Because the workload of transformation is relatively small, it can not only make the oilfield put into production as soon as possible, but also greatly reduce the one-time investment of the oilfield and improve the economic benefit of the oilfield.
The Pearl of Bohai Suizhong 36- 1 Oilfield Experimental Area was rebuilt and used in Penglai 19-3 Oilfield, while BZ28- 1 Oilfield Friendship was moved to CFD 1-6 Oilfield, and now it is undergoing equipment maintenance and partial renovation, and then it returns to its original position and continues to be used for the development of Bonan Oilfield Group for 20 years.
6. Short construction period
After 10 years of engineering practice, the design and construction of floating production and storage devices have gained quite mature experience in China. It generally takes only 1 ~ 1.5 years to build a 65438+ million-ton floating production storage device, which is similar to the construction period of a large block. In addition, because there are no other additional requirements for FPSO's ship type, in the case of urgent need of production in the oilfield, an appropriate old tanker can be selected for reconstruction, and a production process module can be added on its deck, which can be put into use after being connected with the single-point mooring system, thus shortening the construction period. Like several oil fields in the South China Sea, most old oil tankers can be rebuilt within 1 year.