Recently, China National Offshore Oil Corporation (CNOOC) announced that China's first independently designed ultra-deep large-displacement well, the Enping 21-4 oilfield A1H well, has commenced operations. The well is located in the Pearl River Estuary waters and has a tested daily production capacity of over 700 tons of crude oil. It has a drilling depth of 9,508 meters and a horizontal displacement of 8,689 meters, making it the deepest well in China's seas and setting a record for the country's horizontal drilling length. This marks a successful breakthrough in the technical bottleneck of 10,000-meter-class large-displacement wells, positioning its offshore drilling capabilities among the world's leading.

The Enping 21-4 oilfield, about 200 kilometers southwest of Shenzhen, operates in waters with an average depth of around 86 meters. CNOOC has leveraged an unmanned platform "Enping 20-5", positioned 8 kilometers away, for extended-reach drilling, which can efficiently exploit the oil and gas resources of marginal oilfields.

Extended-reach wells are cutting-edge technologies that challenge drilling limits and are recognized globally as one of the most technically challenging endeavors in the industry. At the Enping 21-4 oilfield A1H well, the HD/VD Ratio reaches an impressive 4.43, which means that for every 1-meter descent, the drilling equipment needs to make a large stride of nearly 4.5 meters forward. This requires drilling equipment to traverse over 8,000 meters without the assistance of gravity, relying solely on external driving forces.

Guo Yongbin, Chief Engineer of CNOOC Shenzhen Branch, stated that extended-reach wells are crucial for efficiently exploring and developing oil and gas resources in complex regions such as the ocean and mountainous areas. The Enping 21-4 oilfield's ultra-deep extended-reach well has set four national records and yielded five categories of 13 technological achievements, with 95% of the materials and equipment used being domestically produced. This model has the potential to unlock oil and gas resources within a 10,000-meter radius of production platforms, significantly enhancing the efficiency of oil and gas field development.

According to statistics, China has implemented approximately 350 extended-reach wells offshore in recent years, with total drilling footage of 1.745 million meters, equivalent to drilling through nearly 200 Mount Everest. This places China at the forefront of the world in terms of operational scale, average efficiency, maximum HD/VD ratio, and target accuracy.

Source :Yangcheng Evening News

9508米！中国海上第一深井顺利投产

近日，中国海油宣布，中国首口自主设计实施的超深大位移井——恩平21-4油田A1H井在珠江口盆地海域顺利投产，测试日产原油超700吨。该井钻井深度9508米，水平位移8689米，成为中国海上第一深井，同时创造中国钻井水平长度纪录，标志着中国成功攻克万米级大位移井技术瓶颈，海上超远超深钻井技术水平跨入世界前列。

该超深井开发的恩平21-4油田位于深圳西南方约200公里的海域，平均水深约86米。中国海油利用8公里外的恩平20-5无人平台，实施超深大位移井，可以高效开发边际油田的油气资源。

大位移井是挑战钻井极限的尖端科技，也是全球行业公认的技术难题之一。恩平21-4油田A1H井水垂比达4.43，相当于每下一个1米的台阶，就要往前迈出近4.5米的大跨步，钻具在缺少重力推动下，必须依靠外部驱动力穿行8000多米。

中国海油深圳分公司总工程师郭永宾表示，大位移井是高效勘探开发海洋、山地等复杂地带油气资源的重要手段，此次恩平21-4油田超深大位移井刷新4项全国纪录，形成5类13项技术成果，使用的材料、装备国产化率达95%。依托该模式未来可实现在生产平台1万米范围内的油气资源动用，显著提高油气田开发效益。

据统计，近年来中国海上实施大位移井约350井次，钻井进尺达174.5万米，相当于钻穿近200座珠穆朗玛峰。作业规模、平均时效、最大水垂比、中靶质量等均居于世界前列。

文｜记者 董鹏程
翻译｜史洋溢