摘要
本文根据中国8个油田中150个井段的水压致裂资料,研究了各地区的水平应力随深度的变化,发现平均水平应力和垂直应力的比值在4000m深处大体上在0.8至1.2范围内,高值对应逆断层,低值对应正断层,实测结果与各地区断层活动特征相互一致.将各区实测最大水平主应力值均归算到海平面以下4000m深处.可以看出,最大水平主应力是随着对印度板块一欧亚板块间的缝合线的距离增加而减小,这与用震源机制作出的中国大陆主应力方向的辐射状分布所暗示的力源中心之推断相互印证.本文还利用压裂曲线试验求取岩层之原地抗张强度,实际结果表现出一定的规律性,强度随岩层之埋深而增加,也随埋藏年代之对数而线性增加,这些强度数据也与实验室结果大体相符.
Based on the data of hydrofracturing from 150 segments in 8 oil fields in China, in this paper, we studied the variation in horizontal stress with depth in some areas, and found that the ratios of average horizontal stress to vertical stress are about 0.8-1.2 at the depth of 4000 m, the high values corresponding to reverse faults, and low ones to normal faults. The results of in situ measurements coinside with the features of fault activity in every area. We find that the more distant from the boundary between the Eurasian and Indian plates the less the maximum horizontal stress becomes; the values are normalized to the depth of 4000 m with respect to the sea level after making the elevation correction of well sites. This result and the hypothesis of Force Source Center hinted by the radiant distribution of the direction of the principal stress in the China mainland from focal mechanisms solutions support each other. We also got the in-situ tensile strength of rocks by use of the hydrofracturing curve tests. The actual result shows a certain degree of regularity: the strength increases with the depth of rocks, also varies linearly with the logarithm of the age of rocks. These field strength data coinside roughly with experimental results.
出处
《地震学报》
CSCD
北大核心
1989年第2期142-152,共11页
Acta Seismologica Sinica
