摘要
针对煤层气开发压裂及储层各向异性特点,考虑人工裂缝与各向异性对煤层气压力传播的影响,提出用均衡降压使产气量最大化的思路并进行井网井距优化,在充分考虑各向异性煤层与水力压裂直井压力传播特点的基础上,建立了各向异性地层压裂直井最优井距模型,运用CMG软件GEM模型煤层气模块对模型进行验证.结果表明:对于各向异性煤层或压裂直井,选择矩形或菱形井网较正方形井网好;各向异性煤层矩形井网长宽比按照渗透率比的平方根确定为最优;而对于压裂直井,矩形井网按照长度与宽度的平方差等于4倍裂缝半长的平方确定;对于各向异性煤层与压裂井综合情况,井距关系受各向异性渗透率比值与人工裂缝长度共同影响.在此基础上,建立了煤层气井网井距优化流程,为煤层气开发方式的制定提供了理论方法.
For the characteristics of hydraulically fracture and anisotropy of coalbed methane reservoirs, this study proposed that using balanced depressurization makes the gas output max- imize and optimizes the well pattern and spacing. Taking a full consideration of pressure propa- gation characteristics of anisotropic coal seam and vertically fractured well, this study estab- lished the model of optimal well spacing of anisotropic coal seams and vertical well, and then verified the model using GEM model of CMG software. The results show that： for anisotropic coal seam and vertically fractured well, the well pattern that is rectangle or rhombus is better than the one that is square＇s the optimal length-width ratio of rectangle well pattern in the ani- sotropic coal seam is determined in terms of square roof permeability ratio; as for vertically fractured well, square difference of length and width of rectangle well pattern is equal to 4 times of half-length square of fracture; in the ease of anisotropic coal seam and fracture well,well spacing relation is influenced by the specific value of permeability ratio and the length of hydraulic fracture. Based on this, this study establishes the optimal flow of well pattern and spacing of coal-bed methane, and provides correlation of theoretical method for designing the development mode of coal-bed methane.
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2014年第1期88-93,共6页
Journal of China University of Mining & Technology
基金
国家重大基础研究发展计划(973计划)项目(2009CB219606)
国家科技重大专项(2011ZX05038-4)
关键词
煤层气
各向异性
水力裂缝
均衡降压
井网井距
coalbed methane
anisotropy
hydraulic fracture
balanced depressurization
wellpattern and spacing
