贵州宝元构造嘉五~1储层裂缝预测

PREDICTION OF FRACTURES IN T_(1j1)~5 RESERVOIR IN BAOYUAN STRUCTURE, GUIZHOU PROVINCE

从宝元构造现今构造形迹特征入手 ,利用有限元数值分析技术 ,模拟了嘉五1 储层段的古构造应力场(应力的大小、方向、性质及应力分布等值线图 ) ;然后以岩石破裂强度理论为依据 ,结合岩石的实际力学性质参数 ,计算了嘉五1 层岩体的破裂接近程度 ;以此为依据 ,对嘉五1 储层段裂缝的发育程度、类型及方位分别进行了预测。结果表明 :嘉五1 层裂缝较发育 ,主要发育在宝元构造高点部位及其附近地区 ;储层岩体在两期构造应力场作用下共形成了二期 5组裂缝 ;裂缝类型以早、晚高角度共轭剪切缝和张性缝为主 ;晚期裂缝较早期发育 ;裂缝的主要延伸方向以北西 -南东向为主。根据上述预测结果部署了 1口水平井 (宝平 1井 ) ,根据测井解释结果 ,结合气测、钻时资料分析得出的裂缝实际方位、发育位置等结果与预测完全相符。

Proceeded with the characters of the present structural features of Baoyuan structure, the palaeostructural stress fields(including the magnitude, direction and nature of the stress and the contour map of stress distribution) of the T 1 j 5 1(the first submember of the fifth member of Jialingjiang Formation, Lower Triassic) reservoir was simulated by use of the finite element numerical analysis technique; then, in light of the rock burst strength theory, the burst proximity of the rocks in T 1 j 5 1 was calculated in combination with the actual parameters of rock mechanical properties; and then the development extent, type and direction of the fractures in T 1 j 5 1reservoir were predicted according to this method mentioned above. In light of the research results, it was indicated that the fractures in T j 1 5 1 are developed and they are mainly distributed over the high portion of Baoyuan structural and its vicinal areas; two periods five groups of fractures were formed in total in the reservoir rocks under the action of tectonic stress fields in two phases; the early and late high angle conjugated shear fractures and tension fractures occupy the leading position; the late formed fractures are more developed than the early formed ones; and the fractures with a northwest-southeast extent are in the majority. Well Baoping 1(a horizontal well) was deployed according to the result predicted and the fracture developed actual direction and positions achieved by analyzing the hydrocarbon well logging and drilling time log and by interpreting the log data are completely coincident with the forecast result.