摘要
国内外煤层气研究成果和生产实践证明,需要不同类型的钻井开发煤阶、含气量、含水量等关键参数相异的煤层,以实现煤层气产能最大化。作为一个新的钻井类型,研究"U"型井适合钻探的煤层类型对于提高其产能,实现中国煤层气产业化至关重要。为此,选取沁水、鄂尔多斯盆地等中、高煤阶盆地,根据其地质资料及煤层气生产资料,从煤阶、煤层厚度、煤割理与钻进方向关系、含水量、煤层倾角等方面阐述了"U"型井钻井适应性,认为低煤阶煤层因硬度、密度低,采用"U"型井钻探容易引起坍塌;"U"型井采用两井连通、地质导向、远距离穿针等新技术,而厚煤层在有效使用这些技术的同时,更容易实现在煤层中钻进;"U"型井具有水平井和直井两个井口,可以更有效排出高含水煤层中的承压水,同时也可利用煤层坡度,将直井设置在煤层下倾方向,利用重力排水采气;"U"型井中的水平井具有方向性,垂直于面割理方向钻进可以获得较大产能。以上研究成果表明:"U"型井可以有效开发割理发育、具一定倾角、高含水的中高煤阶厚储层。该研究成果为"U"型井高效开采煤层气指明了方向。
Research results and production practice at home and abroad prove that various kinds of wells are needed for developing the coal beds with different rank and gas content as well as the water content so as to realize coalbed methane productivity maximize.As a new kind of drilling well ,it is important for the China coalbed methane production to study the adaptability of the U-shape wells for the type of coal beds.So,high and middle rank basins are chosen such as Qinshui and Ordos basin.According to their geological and pro- duction data,the adaptability of the U-shape well is discussed from the rank,seam thickness,relation between cleat and drilling direction,water content,seam dip and so on.It shows that low-rank coal beds are easy to collapse when the U-shape wells are drilled because of their low hardness and density.Two-well connection, geosteering,remote ＂threading a needle＂ and some other new technologies are adopted in U-shape well drilling,which are available for the thick coal beds drilling easier.The U-shape well has two heads of hori- zontal well and vertical well.Confined water in the coal beds with high water cut may be discharged effec- tively,and water discharge and gas production may be done using gravity when the vertical well is located in the downdip direction of the coal beds along with the slope of the coal beds.The horizontal well among the U-shape wells has orientation,and more productivity may be gained while drilling perpendicular to the face cleat direction.The above research results show that the U-shape well may be applied for developing the middle and high rank thick coal beds with developed cleat,certain dip and high water cut.It shows di- rection of efficient development by the U-shape well for the coalbed methane.
出处
《中外能源》
CAS
2011年第12期33-36,共4页
Sino-Global Energy
基金
国家重大专项36"煤层气钻井工程技术及装备研制"项目资助(项目编号:2008ZX05036)
