Setting A Record For The Horizontal Length Of Drilling in My Country, The First Deep Well in An Offshore Oil Field Was Put Into Production
Apr 13, 2024
On April 13, CNOOC announced that Well A1H of the Enping 21-4 Oilfield, my country's first independently designed and implemented ultra-deep extended reach well, was successfully put into production in the Pearl River Mouth Basin, with a tested daily crude oil production of over 700 tons. The well has a drilling depth of 9,508 meters and a horizontal displacement of 8,689 meters. It has become the deepest offshore well in my country and set a record for the horizontal length of drilling in my country. It marks that my country has successfully overcome the technical bottleneck of 10,000-meter-level extended reach wells and has reached a new level in offshore ultra-long and ultra-deep drilling technology. Be among the best in the world.
The Enping 21-4 oil field developed by this ultra-deep well is located in the sea about 200 kilometers southwest of Shenzhen, with an average water depth of about 86 meters. It is a small sandstone marginal oil field. If the traditional mode of mining is adopted, new offshore production platforms or underwater wellheads and other facilities need to be built, which requires large investment, long construction period, and no economic benefits. CNOOC uses the Enping 20-5 unmanned platform 8 kilometers away to implement ultra-deep extended reach wells to economically and efficiently develop oil and gas resources in marginal oil fields.
Extended reach wells are cutting-edge technologies that challenge the limits of drilling and are also one of the recognized technical problems in the global industry. The water-to-vertical ratio of Well A1H in the Enping 21-4 Oilfield reaches 4.43, which is equivalent to taking a step forward of nearly 4.5 meters for every step of 1 meter. The drilling tool is almost "lying horizontally" in the posture. In the absence of gravity, it must rely on external driving force to travel more than 8,000 meters.
The project team independently developed new equipment such as environmentally friendly oil-based drilling fluids and continuous circulation systems. During the construction process, advanced technologies such as intelligent guidance while drilling, real-time collection of downhole parameters, and rotating and floating casing were used to allow the drill bit to accurately penetrate three underground faults. , driving 669 high-strength steel casings with a total weight of 564 tons to be smoothly lowered, establishing a stable oil production channel, and the operating capacity has reached the world's advanced level. The ultra-deep extended-reach well in the Enping 21-4 oil field broke four national records and formed 13 technical achievements in five categories. The localization rate of the materials and equipment used reached 95%.
