抽吸式微取心PDC钻头的研究与应用

发布时间：2018-12-13 17:05

【摘要】：常规PDC钻头切削产生的粉状或片状岩屑颗粒不便于地质录井,对此提出了一种新型抽吸式微取心PDC钻头。该抽吸式微取心PDC钻头取消了常规PDC钻头心部的主切削齿,设置特殊的水力结构,使钻头心部在钻进过程中形成一定直径的竖直岩心并适时折断,通过负压抽吸作用将断的微岩心从钻头体内部流道带离井底。结合破岩仿真与液固两相流理论,研究了在岩心、岩屑与钻井液混合流动的流场中,射流喷嘴直径的大小对取心通道中抽吸效果的影响规律。数值模拟结果表明,对于拟定条件下钻头直径为215.9 mm的微取心PDC钻头,当射流喷嘴直径为8 mm时,从排心孔排出的岩心、岩屑和钻井液的质量较高,其负压腔的抽吸效果较好。室内及现场试验表明:采集的岩心以柱状为主,岩心完整性和采集率高;在磨溪111井位嘉陵江组二段3亚段至长兴组上部地层,获总进尺805.65 m,平均机械钻速为4.57 m/h,最高机械钻速可达7.4 m/h;该钻头在嘉陵江组二段3亚段至飞仙关组一段(总进尺742 m)的机械钻速比该区块同层位的其他常规PDC钻头高出了50%以上。
[Abstract]:The pulverized or flake cuttings produced by conventional PDC bit cutting are not convenient for geological logging. A new type of sucking and coring PDC bit is proposed in this paper. The suction micro-coring PDC bit cancels the main cutting teeth in the core of the conventional PDC bit, and sets up a special hydraulic structure to make the core of the bit form a vertical core of certain diameter and break at the right time. The broken microcore is removed from the bottom of the well by negative pressure suction. Based on the theory of rock breaking simulation and liquid-solid two-phase flow, the influence of the diameter of jet nozzle on the suction effect in core, cuttings and drilling fluid mixed flow field is studied. The numerical simulation results show that when the diameter of jet nozzle is 8 mm, the core, cuttings and drilling fluid discharged from the core hole are of high quality for the micro-coring PDC bit with a diameter of 215.9 mm. The suction effect of negative pressure cavity is better. The indoor and field tests show that the core collected is mainly columnar, and the integrity and collection rate of the core are high. From the 3rd submember of Jialingjiang formation to the upper formation of Changxing formation in Moxi 111 well position, the total length is 805.65 m, the average drilling speed is 4.57 m / h, and the maximum mechanical drilling speed is 7.4 m / h; The mechanical drilling speed of this bit from the third submember of the second stage of Jialing River formation to the first section of Feixianguan formation (total ruler 742m) is more than 50% higher than that of other conventional PDC bits in the same layer of the block.
【作者单位】：西南石油大学机电工程学院;中国石油天然气集团川庆钻探工程公司川东钻探公司;四川深远石油钻井工具股份有限公司;
【基金】：国家重大科技专项“深层页岩气开发关键装备与工具研制——钻完井关键工具研制”(2016ZX05038-005)资助
【分类号】：TE921.1

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