低级序复杂断块构造应力场定量模型与油气分布

TECTONIC STRESS FIELD QUANTITATIVE MODEL AND PETROLEUM DISTRIBUTION IN LOW-ORDER COMPLEX FAULT BLOCKS

在对现河低级序帚状断块构造体系研究的基础上,建立了沙一、东营及现今3期构造应力场定量模型,研究了构造应力场特征及其与油气分布的关系。研究表明,不同地质时期应力强度不同,应力的方向和大小都有变化,认为应力值由老到新呈增大趋势。最大水平主应力在平面上自帚状构造的撒开端向收敛端逐渐变低,在剖面上随深度增加而增加,断裂带是应力低值区,也是油气富集区。提出应力转换带为应力低值区,也是低幅断鼻构造的有利分布区,还是开发中后期复杂断块油藏剩余油富集区。

Quantitative models of three phases of tectonic stress fields, i. e. the phase of the First Member of the Shahejie Formation, Dongying Formation phase and the present phase, are constructed based on a study of the Xianhe low-order brush fault block system, and the characteristics of the tectonic stress fields and relation between the stress fields and hydrocarbon distribution are studied. Study indicates that the intensity, direction and magnitude of stress vary in different geologic periods. The stress values show a trend of increase from the old to young formations. The maximum horizontal principal stress in the tectonic stress fields becomes gradually low from the divergent side to convergent end of the brush structure in plan views and increases with depth in section. So the fault zone is a low-stress area and also an area for hydrocarbon accumulation. The authors propose that the stress transition zone is a low-stress area and a favorable area of low-amplitude faulted nose structure, as well as an area of residual oil in a complex fault block oil accumulation in the middle and late stages of petroleum exploitation.