【摘要】 由于煤层天然裂缝发育、对应力敏感以及煤岩较软、易碎等因素,造成煤层气压裂滤失量较大,常用的Carter计算滤失的方法已经不再适用。针对这一问题,作者考虑裂缝内的压力与地层压力之间的压差,对煤层渗透率和孔隙度的影响,并根据相应的计算方法,在Carter方法的基础上对其中的滤失系数进行修正,可以计算出综合滤失系数和滤失量。通过计算实例,并与Carter计算结果进行对比,表明本文所提出的方法比较符合实际。更多还原

【Abstract】 Because of the influencing factors,such as the existing of natural fractures,the stress sensitivity,the softness and frailty of the coal formation,the leak-off volume is great in the hydraulic fracturing of coal-bed methane and the usual Carter’s calculating leak-off method has not been applicable.From the view that the pressure difference between fracture and formation affects severely the permeability and porosity of the coal formation,this paper provides a new mathematical model and the related calculation methods.Finally,one field case example is illustrated and compared with the Carter’s method.It is concluded that the new method is more applicable for the field situations.更多还原