Evidence of the existence of faults, how to identify the existence of faults

Surface identification: Rock formations from the same historical period have essentially the same physical and chemical characteristics (e.g., radioisotope identification and petrochemical composition), and this also coincides if they contain fossils (mainly microscopic e.g., pollen).

Deep Crustal Identification:

Using the first wave signal for simulation and digital processing, the depth and physical characteristics of the layer can be determined according to the waveform, velocity, etc., so as to determine the existence and location of the fault, and finally proved by drilling coring. This is a frequently used method in geophysical prospecting.

The above is an aspect that I am familiar with.

Let's guess what you might mean, because your question is under the category of "social livelihood, law".

There are cultural faults, technology faults, and census faults. Identifying whether there is organic continuity of cultural fault through cultural development, science and technology is easy to see, mainly the depth and breadth of self-development, and the population is clear at a glance.

Faults generally depend on whether his rocks are out of place.

Summary. The signs of the occurrence of faults are as follows: 1. Geological bodies such as strata,, and ore veins are suddenly interrupted or staggered in the plane or profile.

2. Repeat or lack of strata, which is a common phenomenon of normal faults or reverse faults that are roughly parallel to the stratum trend, in the case of the fault tendency and stratigraphic tendency, or the same tendency of the two but the fault dip angle is less than the stratum dip angle, the stratum repeat indicates that it is a normal fault, and the stratum is missing. 3. Friction marks, the traces left by the friction between the two rocks on the fault plane, can be used to identify the direction of movement of the two disks and determine the nature of the fault. 4. Traction structure, the local arc bending caused by the drag of the rock layer near the fault during the fault movement, and the direction of its protrusion roughly indicates the relative movement direction of the plate.

The signs of the occurrence of faults are as follows: 1. Geological bodies such as strata,, and ore veins are suddenly interrupted or staggered in the plane or profile. 2. Repeat or lack of strata, which is a common phenomenon of normal faults or reverse faults that are roughly parallel to the stratum trend, in the case of the fault tendency and stratigraphic tendency, or the same tendency of the two but the fault dip angle is less than the stratum dip angle, the stratum repeat indicates that it is a normal fault, and the stratum is missing.

3. Friction marks, the traces left by the friction between the two rocks on the fault plane, can be used to identify the direction of movement of the two disks and determine the nature of the fault. 4. Traction structure, the local arc bending caused by the drag of the rock layer near the fault during the fault movement, and the direction of its protrusion roughly indicates the relative movement direction of the plate.

A fault is a structure in which the crustal rock layer is fractured due to a certain strength and has obvious relative movement along the rupture surface. The length of the faults varies widely, from a few centimeters to hundreds of kilometers.

The occurrence of faults can be determined through the determination of faults and the combination of faults, and some of the stratigraphic occurrences, fluid properties changes and injection-production dynamic contradictions caused by the existence of faults can also prove the existence of faults, although the fault occurrence cannot be determined, but can be used as a reference basis for compiling structural profiles and plans.

1.Abrupt changes in the thickness of the same layer over short distances.

The sudden change in the thickness of the same layer caused by the duplication or absence of strata (Fig. 4-8) can be judged by the subdivision comparison of the strata.

2.In close proximity, there is a huge difference in the elevation of the standard layer.

Figure 4-8 Schematic diagram of the same set of stratum thickness anomalies caused by faults.

Figure 4-9 Schematic diagram of the large difference in elevation of the standard layer caused by faults.

3.Changes in the properties of oil.

Due to the cutting of faults, the same oil layer becomes disconnected faults. The oil and gas in each fault block are accumulated and preserved under different geochemical conditions, so the properties of the fault block are obviously different. As shown in Figure 4-10, the density curve, glue content and wax content curves of the Tongyan bend oil layer have obvious variations on both sides of the fault.

4.Convert the difference between pressure and oil-water interface.

Due to the cutting effect of the fault, the oil layers on both sides of the fault are at different depths and are not connected to each other, forming an independent pressure system. In the same pressure system, the pressures are conducted to each other until equilibrium, so the converted pressure of each well is equal; However, the converted pressure is completely different for different pressure systems (Figure 4-11). In the same way, the elevation of the oil-water interface is completely different on both sides of the fault.

5.Dynamic contradictions.

Due to the small scale of the faults or the large spacing of the wells, the existing well pattern cannot drill and identify all faults, in which case the existence of faults can be determined by dynamic analysis. For example, in the oilfields with good continuous reservoir injection, some oil production wells have no effect on long-term water injection (mainly manifested in the acceleration of production decline, the decrease of formation pressure, and the increase of oil and gas production). In this case, there must be a discontinuity in the reservoir between the injection well and the production well.

If the cause of the peak extinguishing of the reservoir is ruled out through the study, then it can be determined that there must be a fault between the injection-production wells.

Figure 4-10 Schematic diagram of the variation of the properties of the same oil layer caused by faults.

Figure 4-11 Schematic diagram of the difference in converted pressure of the same oil layer caused by faults.

Rocks are broken, valleys and rivers are located, and springs are developed near the fault line.

Horizontal displacement of faults - can dislocate various original landforms, or derive several tectonic landforms near fault zones.

The staggered landforms such as the gully are cut off, the alluvial fan is horizontally staggered to form the eyebrow ridge, the valley is dislocated, and the upstream is blocked to form a small lake.

Derived tectonic landforms include tectonic landforms at fault bends, tectonic landforms at the end of oblique faults, tectonic landforms near fault ends, and tectonic landforms at fault convergence or dispersion.

When two adjacent blocks are displaced along a trend-bending translational fault, two tectonic landforms appear at the fault bend: one is that the tensile stress causes the crust to sink into a depression or basin; First, the compressive stress makes the earth's crust uplift into a high ground.

Oblique faults, where the end and end meet, if squeezed, the earth's crust is uplifted into a highland, and if it is stretched, the earth's crust sinks into a depression.

When a straight fault moves horizontally, the fault near the end of the fault in front of the fault block movement is uplifted into a platform or hill due to compression. The vicinity of the end of the movement of the fault block is dented due to tension. As a result, two uplift zones and two depression zones were formed on both sides of the fault.

When the main fault and the branch fault intersect, the fault movement has a convergence direction and a spreading direction. When the two faults converge, the wedge-shaped block between the faults will be extruded and uplifted into highland. When the two faults are scattered, the wedge-shaped massif is stretched and descends to lowland.