Analysis and jet drilling test of coiled tubing drilling string for underground coal mine

Authors

YAO Ningping, China Coal Research Institute, Beijing 100013, China; CCTEG Xi’an Research Institute (Group) Co., Ltd, Xi’an 710077, ChinaFollow
WANG Li, China Coal Research Institute, Beijing 100013, China; CCTEG Xi’an Research Institute (Group) Co., Ltd, Xi’an 710077, ChinaFollow
ZHANG Jinbao, CCTEG Xi’an Research Institute (Group) Co., Ltd, Xi’an 710077, China
DOU Xuqian, China Coal Research Institute, Beijing 100013, China; CCTEG Xi’an Research Institute (Group) Co., Ltd, Xi’an 710077, China
WEI Hongchao, China Coal Research Institute, Beijing 100013, China; CCTEG Xi’an Research Institute (Group) Co., Ltd, Xi’an 710077, China

Abstract

Due to continuous tripping, uninterrupted circulation and other technical advantages, coiled tubing drilling has become one of the fastest developing oil-drilling-technologies in recent years. Developing the coiled tubing drilling technology for underground coal mine is an essential technical means to realize “less humanized” or even “unhumanized” coal drilling. Aiming at solving the key problems existing in the application of this technology in underground coal mine, such as pipe string optimization and drilling method, the coiled tubing jet directional drilling method was proposed. According to the mud pump capacity and borehole depth design for underground coal mine drilling, the fluid friction resistance of coiled tubing with different diameters and bending ratios (r₀/R_b) was analyzed. Numerical simulation was used to analyze the buckling morphology of horizontal drilling string and the contact stress with borehole wall at different ratios of coiled tubing diameter to borehole diameter (r_c). Besides, the optimum jet bit parameters were given through the study on rotary jet hydraulic parameters and rock breaking effect test. Specifically, the deviation rule of jet directional drilling, as well as the relationship of different flow rate, drilling speed and borehole diameter, were studied based on the coiled tubing jet directional drilling test. The results show that the bending radius ø19 mm‒ø31.75 mm of coiled tubing can meet the space requirements of coal mine tunnel. Tubing diameter and flow rate are the main factors affecting the fluid friction resistance of coiled tubing. Under the conditions of a flow rate of 200 L/min, a pressure of 31.5 MPa and a drilling depth of 200 m, ø31.75 mm coiled tubing is preferred for the optimal drilling string scheme. When the tube hole ratio is r_c=0.454, the contact stress between the coiled tubing and borehole wall is stable and the compressive stress changes linearly. Drilling with ø34.5 mm/5×1.0 mm jet bit + ø40 mm hydraulic commutator + ø31.75 mm coiled tubing assembly, the average inclination increase capacity was 0.67 (°)/m, the average inclination decrease capacity was 0.61 (°)/m, and the average azimuth increase/decrease capacity was 0.45 (°)/m. By controlling the jet flow rate and drilling speed, the borehole diameter can be controlled around ø70 mm. Generally, the research results could provide a theoretical foundation for the development of coiled tubing drilling technology and equipment in underground coal mine.

Keywords

coiled tubing drilling, fluid friction, rotating water jet, directional drilling, underground coal mine

DOI

10.12363/issn.1001-1986.22.09.0720

Recommended Citation

YAO Ningping, WANG Li, ZHANG Jinbao, et al. (2023) "Analysis and jet drilling test of coiled tubing drilling string for underground coal mine," Coal Geology & Exploration: Vol. 51: Iss. 1, Article 6.
DOI: 10.12363/issn.1001-1986.22.09.0720
Available at: https://cge.researchcommons.org/journal/vol51/iss1/6

Reference

[1] 姚宁平,王毅,姚亚峰,等. 我国煤矿井下复杂地质条件下钻探技术与装备进展[J]. 煤田地质与勘探,2020,48(2):1−7.

YAO Ningping,WANG Yi,YAO Yafeng,et al. Progress of drilling technologies and equipments for complicated geological conditions in underground coal mines in China[J]. Coal Geology & Exploration,2020,48(2):1−7.

[2] 石智军,姚克,姚宁平,等. 我国煤矿井下坑道钻探技术装备40年发展与展望[J]. 煤炭科学技术,2020,48(4):1−34.

SHI Zhijun,YAO Ke,YAO Ningping,et al. 40 years of development and prospect on underground coal mine tunnel drilling technology and equipment in China[J]. Coal Science and Technology,2020,48(4):1−34.

[3] 王清峰,陈航. 瓦斯抽采智能化钻探技术及装备的发展与展望[J]. 工矿自动化,2018,44(11):18−24.

WANG Qingfeng,CHEN Hang. Development and prospect on intelligent drilling technology and equipment for gas drainage[J]. Industry and Mine Automation,2018,44(11):18−24.

[4] 杨林. 煤矿井下瓦斯抽采钻孔机器人研究现状及关键技术[J]. 煤矿机械,2018,39(8):60−62.

YANG Lin. Research status and key technology of underground gas drainage drilling robot in coal mine[J]. Coal Mine Machinery,2018,39(8):60−62.

[5] RAMOS A B,FAHEL R A,CHAFFIN M,et al. Horizontal slim−hole drilling with coiled tubing:An operator ’s experience[J]. Journal of Petroleum Technology,1992,44(10):1119−1125.

[6] KRUEGER S，GRAY K，KILLIP D. Fifteen years of successful coiled tubing re–entry drilling projects in the Middle East：Driving efficiency and economics in maturing gas fields：SPE/IADC Middle East Drilling Technology Conference & Exhibition[C]. Dubai，2013.

[7] 张文平. 连续管钻井水力轴向振动降摩减阻机理研究[D]. 北京：中国石油大学(北京)，2019.

ZHANG Wenping. Research on the mechanism of friction reduction of the hydraulic axial vibration in coiled tubing drilling[D]. Beijing：China University of Petroleum (Beijing)，2019.

[8] 李根生,宋先知,黄中伟,等. 连续管钻井完井技术研究进展及发展趋势[J]. 石油科学通报,2016,1(1):81−90.

LI Gensheng,SONG Xianzhi,HUANG Zhongwei,et al. Research progress and prospects of well drilling and completion with coiled tubing[J]. Petroleum Science Bulletin,2016,1(1):81−90.

[9] 任经纬. 连续油管作业管柱力学分析[D]. 北京：中国石油大学(北京)，2017.

REN Jingwei. Mechanical analysis of coiled tubing operation string[D]. Beijing：China University of Petroleum (Beijing)，2017.

[10] 张帅,张燕萍,郭慧娟. 国内外连续管钻井技术发展现状[J]. 石油矿场机械,2019,48(6):77−82.

ZHANG Shuai,ZHANG Yanping,GUO Huijuan. Development status of continuous pipe drilling technology in China and abroad[J]. Oil Field Equipment,2019,48(6):77−82.

[11] SOE S，LAGAT C，EVANS B，et al. The coiled tubing drilling rig for mineral exploration[C]//SPE/ICo TA Coiled Tubing and Well Intervention Conference and Exhibition. 2018：3–7.

[12] 赵章明. 连续油管工程技术手册[M]. 北京：石油工业出版社，2011.

[13] 赵广慧,梁政. 连续油管内流体压力损失研究进展[J]. 钻采工艺,2008,31(6):41−44.

ZHAO Guanghui,LIANG Zheng. Research on pressure loss of fluid in coiled tubing[J]. Drilling & Production Technology,2008,31(6):41−44.

[14] 王弥康,林日亿,张毅. 管内单相流体沿程摩阻系数分析[J]. 油气储运,1998,17(7):22−26.

WANG Mikang,LIN Riyi,ZHANG Yi. Analysis on frictional resistance coefficient of single–phase fluid inside pipeline[J]. Oil & Gas Storage and Transportation,1998,17(7):22−26.

[15] 周博,管锋,周传喜,等. 连续管钻井系统摩阻计算方法与试验研究[J]. 石油机械,2015,43(2):22−26.

ZHOU Bo,GUAN Feng,ZHOU Chuanxi,et al. Calculation and experimental study of friction resistance in coiled tubing drilling system[J]. China Petroleum Machinery,2015,43(2):22−26.

[16] 袁发勇，马卫国. 连续管水平井工程技术[M]. 北京：科学出版社，2018.

[17] SAS–JAWORSKY II A,REED T D. Predicting friction pressure losses in coiled tubing operations[J]. World Oil,1997,218(9):141−146.

[18] 马沈岐,吴雅丽,任瑞玲. 煤矿瓦斯抽采钻进钻具级配技术[J]. 探矿工程(岩土钻掘工程),2009,36(9):28−31.

MA Shenqi,WU Yali,REN Ruiling. Drilling tool grading technique for gas drainage drilling[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling),2009,36(9):28−31.

[19] 李根生,黄中伟,李敬彬. 水力喷射径向水平井钻井关键技术研究[J]. 石油钻探技术,2017,45(2):1−9.

LI Gensheng,HUANG Zhongwei,LI Jingbin. Study of the key techniques in radial jet drilling[J]. Petroleum Drilling Techniques,2017,45(2):1−9.

[20] 董小龙. 连续油管径向旋转喷射钻进的研究[D]. 长春：长春理工大学，2014.

DONG Xiaolong. Study on radial rotary jet drilling of coiled tubing[D]. Changchun：Changchun University of Science and Technology，2014.

[21] 毕刚,李根生,屈展,等. 自进式旋转射流钻头破岩效果[J]. 石油学报,2016,37(5):680−687.

BI Gang,LI Gensheng,QU Zhan,et al. Rock breaking efficiency of the self–propelled swirling jet bit[J]. Acta Petrolei Sinica,2016,37(5):680−687.

[22] 刘勇,陈长江,刘笑天,等. 高压水射流破岩能量耗散与释放机制[J]. 煤炭学报,2017,42(10):2609−2615.

LIU Yong,CHEN Changjiang,LIU Xiaotian,et al. Mechanism on energy dissipation and release of rock breakage with high pressure water jets[J]. Journal of China Coal Society,2017,42(10):2609−2615.

[23] 林柏泉,王瑞,乔时和. 高压气液两相射流多级脉动破煤岩特性及致裂机理[J]. 煤炭学报,2018,43(1):124−130.

LIN Baiquan,WANG Rui,QIAO Shihe. Characteristics and mechanism of multistage fluctuation of coal–breaking caused by high–pressure gas–liquid two–phase jet[J]. Journal of China Coal Society,2018,43(1):124−130.

[24] 徐洋. 水力喷射径向钻孔工艺射流参数研究[D]. 大庆：东北石油大学，2012.

XU Yang. Jet parameters research of hydraulic injection radial drilling technology[D]. Daqing：Northeast Petroleum University，2012.

[25] 肖宋强. 自旋转射流流场特性及破煤岩成孔机理研究[D]. 重庆：重庆大学，2019.

XIAO Songqiang. Flow characteristics and rock–breaking mechanism by water jets generated by a self−rotatory bit[D]. Chongqing：Chongqing University，2019.

[26] 雷顺,高富强,王晓卿. 煤体单轴抗压强度统计与分级研究[J]. 煤炭科学技术,2021,49(3):64−70.

LEI Shun,GAO Fuqiang,WANG Xiaoqing. Study on statistics and classification of uniaxial compressive strength of coal[J]. Coal Science and Technology,2021,49(3):64−70.