塔中工区压裂缝高度预测方法研究

RESEARCH ON THE PREDICTION METHOD FOR HYDRAULIC FRACTURE HEIGHT IN TAZHONG WORK AREA

本文根据压裂段地层垂向应力、最大和最小水平主应力的大小关系确定裂缝的形态及方位;依据压裂段地层和相邻地层最小水平主应力的大小划分出最小水平主应力的低应力段、较高应力段和高应力段,并根据裂缝易向低应力段延伸特点,定性分析裂缝延伸高度与方向;结合断裂力学岩石应力强度因子和断裂韧度关系定量分析裂缝延伸高度与方向。为人工压裂缝预测提供了一套完整的方法,并把此方法应用塔中Ⅰ号气田部分压裂井段,取得了良好的效果。

This paper formulates a method to determine the shape and azimuth of fractures according to the relationship between vertical stress and maximum and minimum horizontal principal stress in fractured interval;to divide low,relatively high and high stress section according to the minimum horizontal principal stress in fractured formation and the adjacent formation;to analyze the height and direction of fracture stretch qualitatively according to the characteristics that fractures are easy to stretch to low stress section;to analyze the height and direction quantitatively according to the relationship between rock stress intensity factor and fracture toughness in fracture mechanics.It provides a complete method for man-made fracture prediction which has been applied in part of fracture intervals in Tazhong No.1 gas field and ob- tained favorable result.