油气安全开采中断层稳定性评价
发布时间：2019-06-14 19:49
【摘要】：断层稳定性是指先存断层在应力场条件下发生再活动的风险程度,油田范围内断层再活动主要源于断层带内流体压力的增加。其定量评价指标为当前孔隙流体压力条件下断层再活动所需临界流体压力(即附加流体压力),地层孔隙压力达到临界压力时,相应的断层部位将处于临界应力状态,临界应力断层发生滑动容易造成油气的渗漏以及断层边部井眼套损等问题,因此研究断层稳定性对油田生产具有极其重要的意义。地应力是断层稳定性评价的关键参数,地应力场获取有多种方法,包括水力学方法、声发射法以及测井资料计算地应力等,其中水力压裂法能够获得精确的水平最小主应力的大小,本文利用测井资料进行计算获得了连续的地应力剖面。断层稳定性评价有多种方法,其中FAST(断层封闭性分析技术)方法应用较为广泛,该方法不仅可以对断层稳定性进行定量评价,而且兼顾了断层内聚力对断层稳定性的作用。影响断层稳定性的因素有很多,差应力和断层岩抗张强度的相互关系会影响断层再活动的趋势类型,应力场方向对断层稳定性也有很大的影响;泥质成分对断层岩强度具有弱化作用,有大量泥质卷入的断裂带易于再活动;储层流体压力的变化也会导致水平应力的变化从而对断层稳定性造成影响;此外地震解释精度也会影响断层稳定性的评价结果。本文基于稳定性机理及断层稳定性影响因素分析,在获得地应力、流体压力以及断层力学性质资料的基础之上对渤中34-2/4油田2区Ⅱ、Ⅲ和Ⅳ油组断层稳定性进行了定量评价。渤中34-2/4油田现今应力场环境下沙河街组最优向断层产状为160°∠61.5°和340°∠61.5°,随着地层流体压力持续增加接近该产状的断层部位首先达到临界应力状态。渤中34-2/4油田2区北中块Ⅱ、Ⅲ和Ⅳ油组断层稳定性评价结果显示,Ⅱ油组主要断层不发生再活动所允许的附加流体压力范围为6.1-29.8 MPa,Ⅲ油组主要断层不发生再活动所允许的附加流体压力范围为6.4-29.8 MPa,Ⅳ油组主要断层不发生再活动所允许的附加流体压力范围为6.6-29.7 MPa。断层风险性最大的部位为F30断层上BZ34-2-1井西侧部位以及F31断层北东向末端,现今孔隙压力条件下所能承受的最大流体增压分别为6.5 MPa和6.1 MPa。
[Abstract]:The fault stability refers to the degree of risk that the pre-existing fault occurs under the stress field, and the fault re-activity in the field is mainly due to the increase of the fluid pressure in the fault zone. The quantitative evaluation index is the critical fluid pressure (i.e., the additional fluid pressure) required for the fault re-activity under the current pore fluid pressure condition, and when the formation pore pressure reaches the critical pressure, the corresponding fault part will be in the critical stress state, It is of great significance to study the stability of the fault to the production of the oil field. The ground stress is the key parameter of the fault stability evaluation, and the ground stress field is obtained with a variety of methods, including the hydraulic method, the acoustic emission method and the well logging data to calculate the ground stress, etc., in which the hydraulic fracturing method can obtain the accurate horizontal minimum principal stress, In this paper, the continuous ground stress profile is obtained by using logging data. The fault stability evaluation has a variety of methods, in which the method of the FAST (fault sealing analysis technique) is widely used. The method not only can quantitatively evaluate the fault stability, but also takes into account the effect of the fault cohesion on the fault stability. There are many factors that affect the stability of the fault, and the relationship between the difference stress and the tensile strength of the fault rock can influence the trend type of the fault re-activity, and the stress field direction has a great influence on the fault stability; the argillaceous component has a weakening effect on the strength of the fault rock, The fault zone with a large amount of argillaceous involvement is prone to reactivity; the change of the reservoir fluid pressure can also lead to a change in the horizontal stress, which can affect the stability of the fault; moreover, the accuracy of the seismic interpretation can also influence the evaluation result of the fault stability. Based on the analysis of the stability mechanism and the influence factors of the fault stability, the fault stability of the two zones 鈪，
本文编号：2499640
[Abstract]:The fault stability refers to the degree of risk that the pre-existing fault occurs under the stress field, and the fault re-activity in the field is mainly due to the increase of the fluid pressure in the fault zone. The quantitative evaluation index is the critical fluid pressure (i.e., the additional fluid pressure) required for the fault re-activity under the current pore fluid pressure condition, and when the formation pore pressure reaches the critical pressure, the corresponding fault part will be in the critical stress state, It is of great significance to study the stability of the fault to the production of the oil field. The ground stress is the key parameter of the fault stability evaluation, and the ground stress field is obtained with a variety of methods, including the hydraulic method, the acoustic emission method and the well logging data to calculate the ground stress, etc., in which the hydraulic fracturing method can obtain the accurate horizontal minimum principal stress, In this paper, the continuous ground stress profile is obtained by using logging data. The fault stability evaluation has a variety of methods, in which the method of the FAST (fault sealing analysis technique) is widely used. The method not only can quantitatively evaluate the fault stability, but also takes into account the effect of the fault cohesion on the fault stability. There are many factors that affect the stability of the fault, and the relationship between the difference stress and the tensile strength of the fault rock can influence the trend type of the fault re-activity, and the stress field direction has a great influence on the fault stability; the argillaceous component has a weakening effect on the strength of the fault rock, The fault zone with a large amount of argillaceous involvement is prone to reactivity; the change of the reservoir fluid pressure can also lead to a change in the horizontal stress, which can affect the stability of the fault; moreover, the accuracy of the seismic interpretation can also influence the evaluation result of the fault stability. Based on the analysis of the stability mechanism and the influence factors of the fault stability, the fault stability of the two zones 鈪，
本文编号：2499640
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