压裂水平井增产因素分析与裂缝参数优化

ANALYSIS OF THE PRODUCTION-INCREASING FACTORS AND OPTIMIZATION OF THE FRACTURE PARAMETERS FOR HORIZONTAL WELL FRACTURING

压裂水平井是提高低渗透油气藏单井产能的重要方法，而裂缝半长、裂缝条数、裂缝与水平井筒的夹角等裂缝参数影响压裂水平井的产能。围绕压裂水平井的压力场分布特征、裂缝间干扰特征，分析了影响压裂水平井产能的增产动力因素和增产阻力因素，提出了压裂水平井裂缝参数的优化次序和优化原则。在此基础上，以产能为目标对压裂水平井的裂缝半长、裂缝条数、裂缝与水平井筒的夹角进行了优化研究。结果表明：在进行油气藏储层改造的过程中，应尽可能选择较大的压裂规模；裂缝半长较小时应采用5—6条裂缝进行生产，裂缝半长较大时应采用3—4条裂缝进行生产；选择水平井的方向应充分考虑主应力方向，尽可能保证裂缝与水平井筒的夹角不小于75°；还应充分考虑裂缝分布的影响，“哑铃形”裂缝分布优于“纺锤形”裂缝分布。

Horizontal well fracturing is an important way to improve the individual well＇ s productivity in low-per- meability oil reservoir, but the fracture length, numbers, the included angles between the fractures and horizontal boreholes and other parameters all affect the fractured horizontal well＇s productivity. Focused on the pressure field distribution and interference characteristics among fractures of the fractured wells, the stimulating and damaging factors for the productivity are analyzed, the orders and principles of the optimization of fracture parameters of hori- zontal well fracturing. On the basis of the above ~ taking the productivity as the target, all the parameters above are studied optimally. The results show that in the course of the reservoir stimulation the much larger scale fracturing should be selected as possible as we can; when the fracture half-length is rather shorter, 5 -6 fractures should be adopted to produce ; on the contrary, 3 - 4 fractures should be used ; the direction of horizontal well should be con- sidered as far as possible to integrate the strike of the main stress and ensure the included angle between the frac- tures and the horizontal well not less than 75 ° ; and furthermore the influences of the fracture distribution should be fully taken into account and the ＂dumbbell＂ distribution of fractures is better than the ,i spindle-type＂ one.