苏北盆地戴南组和阜宁组地层取心关键技术

针对苏北盆地戴南组和阜宁组泥岩地层取心钻进中存在的回次取心进尺少、岩心收获率低和取心机械钻速低等技术难点，在分析戴南组和阜宁组泥岩地层特点的基础上，研制了相应的PDC取心钻头，并优选了取心筒、优化了取心水力参数，形成了适用于苏北盆地泥岩地层的取心关键技术。PDC取心钻头以“G系列”齿为主切削齿，同时配合大喷嘴加内规径流道和优化的排屑槽斜面，既能降低岩屑与切削齿表面的摩擦力、改善岩屑运移状态和提高机械钻速，又具有效清洗切削齿、使岩心顺利进入内筒和提高岩心收获率的作用。该取心关键技术在48口井的戴南组和阜宁组地层进行了现场应用，岩心收获率平均大于98.0%，最高机械钻速达到24.80 m/h。苏北盆地泥岩地层取心关键技术解决了戴南组和阜宁组地层取心技术难点，具有较好的推广应用前景。 

Key Coring Technologies for the Dainan Formation and Funing Formation in North Jiangsu Basin

The goal of this study was to develop a coring bit that can overcome the challenges of challenging mudstone rocks. In the mudstone strata of the Dainan Formation and Funing Formation in the North Jiangsu Basin, there are problems such as less footage for each coring, low core recovery and lower coring ROP. After analyzing the geological characteristics and drillability of cored stratum, a PDC coring bit suitable for the Dainan and Funing mudstone strata was developed. This bit adopts the " G series” teeth as the main cutters, and it is fitted with the large nozzle and inner gauge flow channel and applies the optimally designed the slot slope for removing cuttings. It is able to reduce the friction between the cuttings and cutters, improve the cutting migration state and enhance the ROP. Furthermore, it can clean the cutters effectively, and facilitate the core entering the inner barrel, which improves the core recovery significantly. The new coring bit and optimal coring barrel were jointly used to core the Dainan Formation and Funing Formation in 48 exploration wells, with an average core recovery of greater than 98.0% and maximum ROP of 24.80 m/h. By aligning the new coring bit with technologies, researchers solved the coring problems of the Dainan Formation and Funing Formation in North Jiangsu Basin, with good on-site promotion and application value for best practices