阅读说明：本技术 基于动力学平衡原理的走滑断层垂向启闭性评价方法 (Dynamic balance principle-based vertical opening and closing performance evaluation method for strike-slip fault ) 是由 秦峰 宫亚军 王千军 曹忠祥 曾治平 刘慧� 刘华夏 陈雪 范婕 高剑雄 于 2020-05-12 设计创作，主要内容包括：本发明属于油田勘探技术领域,涉及一种基于动力学平衡原理的走滑断层垂向启闭性评价方法。所述方法包括：对研究区走滑断层的启闭性进行动力学表征；依据表征结果对所述走滑断层启闭性建立评价模型,并给出启闭性判识标准。本发明从断层结构强度、有效应力及流体动力三个主要方面剖析了启闭作用,并明确了动力学意义及量化表征,建立评价模型。本发明方法可适用于不同地质条件下的走滑断层的垂向启闭性评价；同时也适用于断层活动期与静止期启闭性的评价。适用范围广,评价准确性提高。(The invention belongs to the technical field of oilfield exploration, and relates to a method for evaluating vertical opening and closing performance of a slip fault based on a dynamic balance principle. The method comprises the following steps: performing dynamic characterization on the opening and closing performance of the walk-slip fault of the research area; and establishing an evaluation model for the opening and closing performance of the walk-slip fault according to the characterization result, and giving an opening and closing performance judgment standard. The method analyzes the opening and closing action from three main aspects of fault structure strength, effective stress and fluid power, determines the dynamic significance and quantitative representation, and establishes an evaluation model. The method can be suitable for evaluating the vertical opening and closing performance of the strike-slip fault under different geological conditions; meanwhile, the method is also suitable for evaluating the opening and closing performance of the fault in the active period and the static period. The application range is wide, and the evaluation accuracy is improved.)

1. A method for evaluating vertical opening and closing performance of a strike-slip fault based on a dynamic balance principle is characterized by comprising the following steps:

step 1, performing dynamic characterization on the opening and closing performance of a strike-slip fault in a research area;

and 2, establishing an evaluation model for the opening and closing performance of the walk-slip fault according to the characterization result, and giving an opening and closing performance judgment standard.

2. The method of claim 1, wherein in step 1, the dynamic characterization of the opening and closing of the fault structure is performed from fault structure strength, effective stress and/or fluid dynamics.

3. The method according to claim 2, characterized in that mudstone plasticity is selected as a kinetic characterization of fault structure strength; preferably, the mudstone plastic deformation limit pressure is taken as the dynamic characterization of the fault structure strength.

4. The method according to claim 3, wherein a relation model of the plastic deformation limit pressure of the mudstone and the burial depth of the breakpoint is established, and the model is a linear relation model or a nonlinear relation model.

5. The method of claim 2, wherein the positive fracture pressure is selected as a dynamic representation of the effective stress.

6. The method of claim 5, wherein a model of the relationship between positive fracture pressure and the depth of the break, the dip angle of the fracture, the water density of the overburden and the rock density of the overburden is established.

7. The method of claim 2, wherein the fluid pressure is selected as a dynamic representation of the fluid dynamics.

8. The method of claim 7, wherein the relationship between the fluid pressure and the breakpoint burial depth is modeled by fitting based on measured pressure data in the region of interest.

9. The method according to claim 1 or 2, characterized in that in step 2, according to the characterization result in step 1 and the basic dynamic balance principle, the conductance capacity of the fault is characterized by using the ratio of flow power to flow resistance, and the on-off evaluation is carried out;

preferably, the determination of whether the mudstone plastic strength, fluid residual pressure and positive fracture pressure are flow dynamics or flow resistance is based on the effective stress, fault structure strength and the role that fluid dynamics play in the geology, respectively.

10. The method according to claim 9, wherein the open/close judgment criterion is:

the ratio of the flow power to the flow resistance is greater than 1, and the fault is opened; the ratio of the flow power to the flow resistance is less than 1, and fault plugging is carried out; the ratio of the flow power to the flow resistance is 1, and the ratio is a fault opening and closing critical value.

Technical Field

The invention belongs to the technical field of oilfield exploration, and relates to a method for evaluating vertical opening and closing performance of a slip fault based on a dynamic balance principle.

Background

The fault is an important link for oil and gas transportation and accumulation, the fault is generally considered to have double functions of transportation and shielding, the transportation and shielding function in the active fracture period is realized, the blocking function is realized in the quiescent period, the core problem of the research is to clarify the space-time boundary of the transportation and shielding functions, aiming at the problem, the research on the transportation and blocking performance of the fault is carried out by predecessors, the influence factors of the transportation and blocking performance of the fault are analyzed, a representative Darcy seepage mechanism driven by buoyancy, a pumping mechanism of a seismic pump and a curtain type transportation mechanism with double control of break-pressure and a geological model of butt joint sealing of the fault lithology and mudstone smearing sealing are provided, and a corresponding evaluation model of the transportation and accumulation performance is established, so that the advantages of the fault transportation and accumulation channel can be drawn, the oil and gas reservoir location and prediction can be realized.

Chinese patent CN106680891B discloses a quantitative evaluation method for the vertical opening and closing performance of a fault in an oil and gas accumulation period, which comprises the following steps: selecting a plurality of faults of an already-detected region in a research region as sample points, manufacturing a longitudinal geological profile perpendicular to the trend of the faults, and judging the vertical opening and closing of the faults of the sample points according to the distribution characteristics of oil gas on an upper plate and an lower plate of the faults; calculating a fault opening and closing coefficient S of the sample point, counting the correlation between the vertical opening and closing of the fault layer of the sample point and the corresponding fault opening and closing coefficient S, and establishing an identification threshold; calculating a fault opening and closing coefficient S corresponding to a fault in an unexplored area in the research area, and when the fault opening and closing coefficient S corresponding to the fault is larger than an identification threshold, vertically closing the fault; otherwise, the fault is opened vertically. The method is suitable for lithologic cover segment evaluation.

Chinese patent CN106772675B discloses a method for evaluating fault opening and closing performance based on fault fracture structure, which comprises the following steps: the fracture structure characteristics of various faults in a target area are determined; acquiring the permeability of different fault structure parts according to the fracture structure characteristics; and calculating the opening and closing probability of the corresponding part by using the permeability of different parts of the fault structure, then calculating the opening and closing probability of the fault of the corresponding layer by using the opening and closing probability of the corresponding part, and then evaluating the opening and closing of the fault of the target area by using the opening and closing probability of the fault of different layers. The method considers various geological factors, and can be widely applied to the technical field of oil and gas resource geological exploration and development evaluation.

At present, research is mainly carried out on a tensile normal fault and a thrust fault, but the two types of faults have larger vertical fault distances, the vertical fault distance of a slip fault is not obvious, and mainly horizontal displacement is taken as a main part, so that the application effect of the conventional evaluation method based on the normal fault or the reverse fault in the slip fault is poor, and the evaluation optimization of favorable targets in oil-gas exploration is restricted. In addition, in recent years, under the promotion of fault structure and fluid dynamics research, the fault is gradually recognized to have a structure of a fault nucleus and a fracture zone, the permeability of each structural unit has obvious difference, the permeability of an induced fracture zone is obviously higher than that of the fault nucleus, and the fluid dynamics characteristic difference in the fracture zone makes fault conduction behavior more complex. Fracture zone fluid conductance is essentially hydrodynamic, but this important element is hardly considered in existing evaluation models. Therefore, the accuracy of the existing evaluation model still needs to be further improved and improved.

Disclosure of Invention

Aiming at the problems, the invention provides an evaluation method suitable for the strike-slip fault, and the method lays a foundation for the unified evaluation of the strike-slip fault conductance during the active period and the static period of the fault by constructing an evaluation model based on dynamic balance.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for evaluating vertical opening and closing performance of a strike-slip fault based on a dynamic balance principle comprises the following steps:

step 1, performing dynamic characterization on the opening and closing performance of a strike-slip fault in a research area;

and 2, establishing an evaluation model for the opening and closing performance of the walk-slip fault according to the characterization result, and giving an opening and closing performance judgment standard.

Preferably, in step 1, the dynamic characterization of the fault opening and closing is performed from the fault structure strength, effective stress and/or fluid dynamics.

Preferably, mudstone plasticity is selected as a kinetic characterization of fault structure strength; preferably, the mudstone plastic deformation limit pressure is taken as the dynamic characterization of the fault structure strength.

Further preferably, a relation model of mudstone plastic deformation limit pressure and breakpoint burial depth is established, and the model is a linear relation model or a nonlinear relation model.

Preferably, the positive cross-sectional pressure is chosen as a dynamic representation of the effective stress.

Further preferably, a relation model between the positive pressure of the fracture surface and the buried depth of the breakpoint, the fault dip angle, the water density of the overlying strata and the rock density of the overlying strata is established.

Preferably, the fluid pressure is selected as a dynamic representation of the fluid dynamics.

Further preferably, a relation model between the fluid pressure and the breakpoint burial depth is established in a fitting mode according to measured pressure data in the research area.

Preferably, in step 2, according to the characterization result and the basic dynamic balance principle in step 1, the conductance capacity of the fault is characterized by using the ratio of flow power to flow resistance, and the on-off evaluation is carried out;

preferably, the determination of whether the mudstone plastic strength, fluid residual pressure and positive fracture pressure are flow dynamics or flow resistance is based on the effective stress, fault structure strength and the role that fluid dynamics play in the geology, respectively.

Preferably, the open-close judgment standard is as follows:

the ratio of the flow power to the flow resistance is greater than 1, and the fault is opened; the ratio of the fluid power to the flow resistance is less than 1, and fault plugging is carried out; the ratio of the flow power to the flow resistance is 1, and the ratio is a fault opening and closing critical value.

The method analyzes the opening and closing action from three main aspects of fault structure strength, effective stress and fluid power, determines the dynamic significance and quantitative representation, and establishes an evaluation model. Compared with the prior art, the invention has the following technical advantages:

(1) the fault has double-layer effects of conductivity and plugging, three evaluation elements of fault structural strength, effective stress and hydrodynamic force selected by the invention can be power effect or resistance effect under different geological conditions, and have double-layer effects of conductivity and plugging, and an evaluation model established based on a dynamic balance principle can be suitable for evaluating the vertical opening and closing performance of the sliding fault under different geological conditions; meanwhile, the method is also suitable for evaluating the opening and closing performance of the fault in the active period and the static period, and the application range is wide.

(2) According to the invention, through systematic analysis of the opening and closing effects of geological elements in three aspects of effective stress, fault structure strength and fluid power, the dynamic effect and quantitative representation of the opening and closing elements are determined, an opening and closing evaluation model and an identification standard are established, and the evaluation accuracy is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

FIG. 1 is a cross-sectional view illustrating a north-south seismic interpretation of a quasi-midriff according to an embodiment of the present invention;

fig. 2 is a chart illustrating vertical conductance evaluation of 1 slice in a quasi-midriff slice according to an embodiment of the present invention.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.

In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.