摘要
沁水盆地南部煤层气水平井开发10 a实践表明,相同地质条件下不同类型水平井开发效果存在较大差异,亟需就水平井开发地质适应性进行深入研究。基于樊庄一郑庄区块水平井开发现状,通过生产数据统计分析,结合煤矿井下观察和室内实验,研究了水平井完井方式、储层改造方式的地质适应性。结果表明,地应力大小、方向和煤体结构决定水平井完井方式。水平井完井方式主要包括裸眼完井、套管或筛管完井等,在保证水平井井眼稳定的前提下采用裸眼完井经济效益最好。但埋深超过600 m时,煤岩承受的垂向应力大于抗压强度,裸眼水平井易垮塌,应使用筛管、套管完井;当埋深为600～700 m时,筛管水平井产量可达3 000 m^3/d以上,可用筛管完井;当埋深大于700 m,需要进行压裂,用套管完井。水平井井眼走向与煤层最大水平主应力方向之间夹角越小,井眼受到的有效应力越大,裸眼井眼越容易变形垮塌,应采用筛管、套管完井,当水平井井眼走向垂直于煤层最大水平主应力方向时,裸眼水平井产量最高,可以采用裸眼水平井完井。水平井井眼穿过碎粒、糜棱煤发育区,裸眼井眼易垮塌,裸眼水平井平均单井产气量仅1 000 m^3/d左右,而筛管水平井可以达到4 500 m^3/d左右,应采用筛管完井。煤层微观裂缝发育程度和垂向非均质性决定水平井是否需要压裂,微观裂缝发育程度可以用裂缝指数定量表征。当裂缝指数高于100时,筛管水平井产量一般高于3 000 m^3/d,开发效果较好;当裂缝指数低于100时,储层渗透性差,单井控制面积小,筛管水平井产量低于1 000 m^3/d,分段压裂后储层渗透率提高,产量达到7 000 m^3/d以上。煤层垂向上存在局部裂缝指数小于100的低渗层时,气体垂向渗流阻力大,筛管井产气效果差,需进行分段压裂,分段压裂水平井产量可达到8 000 m^3/d以上。
The practical development experiences of CBM horizontal well for 10 years in southern Qinshui Basin shows that there is a big development difference among the different types of horizontal wells under the same geological conditions and among the same type of horizontal well under different geological conditions.Therefore,the geological adaptability of horizontal wells needs to further be investigated.This paper studies the effects of key geological parameters of horizontal well on the completion method and the stimulation method,based on present development situation of horizontal wells,coal mine observation and indoor experiments by statistics data in Fanzhuang and Zhengzhuang block.The results show that the size and direction of ground stress and the coal structure decide the completion method of horizontal wells.The completion method consists of open-hole completion,casing completion,screen completion and so on.The open-hole completion is the most economic method if the well bore is stable.When the buried depth is more than 600 m,the vertical stress of the coal and rock is greater than the compressive strength,which results in that the open hole of horizontal well is prone to collapse and the casing completion method and the screen completion method should be adopted.When the buried depth is between 600 m to 700 m,the daily production of screen completion horizontal well can be over 3 000 m 3/d.However,when the buried depth is deeper than 700 m,the hydraulic stimulation is needed,so the casing completion method is suitable.The production of horizontal well decreases with the increase of the angle between the horizontal well borehole trends and the greater the maximum horizontal principal stress direction because the smaller the angle,the greater the effective stress on open hole,and the easier the deformation and collapse of open hole,where the casing and screen completion way should be adopted.When the borehole trend is perpendicular to the direction of the maximum horizontal principal stress,the production o
作者
胡秋嘉
李梦溪
贾慧敏
刘春春
崔新瑞
李玲玉
彭鹤
张光波
毛崇昊
HU Qiujia;LI Mengxi;JIA Huimin;LIU Chunchun;CUI Xinrui;LI Lingyu;PENG He;ZHANG Guangbo;MAO Chonghao(CBM Branch Company,Huabei Oilfield of Petrochina,Jincheng 048000,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2019年第4期1178-1187,共10页
Journal of China Coal Society
基金
国家科技重大专项资助项目(2017ZX05064)
中国石油天然气股份有限公司重大科技专项资助项目(2017E-1405)
关键词
高煤阶煤层气
水平井
井眼稳定性
完井方式
分段压裂
地质适应性
high-rank coal-bed methane
horizontal well
well hole stability
completion way
staged fracturing
geologic adaptability
