The Chinese company CNOOC Limited (a subsidiary of the oil and gas giant China National Offshore Oil Corporation, CNOOC) began production as part of the Enping 21-4 oil field development project.
The company’s press service reported this on June 27, 2024.
Enping 21-4 Field
- opened in 2020;
- part of the Enping group of fields;
- located in the eastern part of the South China Sea, approximately 200 km southwest of Shenzhen;
- the average sea depth at the field is about 86 m;
- the field will be developed using existing production facilities;
- shelf production will be approximately 5.3 thousand boe/stoke in 2025.
Let us recall that in April 2024, at the Enping 21-4 field, CNOOC commissioned the A1H well with a record deviation from the vertical for China:
- the well was constructed from the unmanned platform Enping 20-5, located 8 km from Enping 21-4;
- the length of the wellbore was 9508 m, the deviation from the vertical was 8689 m;
- after testing, the oil flow rate was more than 700 tons/day.
Using ERD wells
The Enping 21-4 field is small in terms of reserves, which makes its development using traditional methods – through the construction of new offshore production platforms (OPPs) or subsea production complexes (SPC) – economically unfeasible. Therefore, for the development of the field, a technology was chosen with the construction of wells with extended reach from the vertical (Extended-Reach Drilling, ERD) with a nearby OPP.
The use of ERD wells allows for economical and efficient development of oil and gas reserves in low-yield oil fields.
The deviation coefficient (ERD) of well A1H in the Enping 21-4 field reaches 4.43, which is equivalent to moving forward nearly 4.5 m for every 1 m depth step.
This is not a record figure on a global scale, but for China it is a very important achievement, since the design and construction of the well was carried out in-house using equipment of its own production.
To implement the project, new technological solutions and materials were developed:
- environmentally friendly petroleum-based drilling fluids and continuous circulation systems;
- intelligent control while drilling;
- collection of downhole parameters in real time;
- rotating and floating casing.
The level of localization of materials and equipment used has reached 95%.
The company notes that the successful use of this development method has served as an example for similar projects of the company.
CNOOC Limited owns 100% interest in this project and acts as operator.
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