Quantitative evaluation method for fault lateral sealability

Abstract

The invention provides a quantitative evaluation method for fault lateral sealability, which belongs to the field of oil and gas exploration. The method considers the formation compaction correction,and can accurately evaluate lateral sealing evolution characteristics of the faults in various periods from the oil and gas accumulation period to the current period. The evaluation method comprisingthe following steps: for each time unit that from the oil and gas accumulation period to the current period, performing restoration on the formation of each time unit from the oil and gas accumulationperiod to the current period according to a decompaction correction; respectively calculating an ancient shale smear factor, an ancient clay smear potential, and an ancient shale gouge ratio corresponding to the single sand layer at different depths in each time unit; calculating a current shale smear factor, a current clay smear potential, and a current shale gouge ratio corresponding to the current period; when the shale smear factor, the clay smear potential, and the shale gouge ratio corresponding to the ancient and the current periods reach the threshold requirement, evaluating that thefaults are laterally sealed; and otherwise, evaluating that the faults have been laterally opened.

Description

technical field [0001] The invention belongs to the field of oil and gas exploration, and in particular relates to a quantitative evaluation method for lateral sealing of faults. Background technique [0002] In faulted basins, faults play a very important role in controlling the migration and accumulation of oil and gas: when faults are active, they can serve as important transport channels for oil and gas migration; when faults cease to be active, they can serve as important barriers for oil and gas accumulation . In oil and gas exploration, determining whether a fault blocks oil and gas is good or bad is the basis for judging the effectiveness of traps and an important prerequisite for the successful deployment of exploratory wells. Therefore, accurate evaluation of the lateral sealing of faults is helpful to analyze the effective sealing area and position of traps and the maximum height of oil and gas columns in traps, and then help to correctly understand the current o...

AI Technical Summary

Problems solved by technology

According to the evaluation results obtained by these three algorithms, there are often cases where traps with very good lateral sealing of faults have no oil and gas accumulation or only oil and gas shows. In the current time period, the paleolateral sealing ability of faults is weaker than the lower limit of sealing oil and gas, which leads to the loss of oil and gas

In this case, the original CSP, SSF and SGR algorithms can no longer meet the evaluation requirements

[0004] Wang Chao (2017) proposed to use the same stratum compaction correction formula to restore the paleoparameters to improve the SGR algorithm, but he ignored the characteristics of differential compaction of the strata on the two sides of the fault, and there are also differences between different strata and different lithologies. There is differential compaction, so the same formula cannot be used to recover the paleo-thickness of different strata on the two sides of the fault

In addition, the method proposed by Wang Chao must rely on the shale content log curve data for calculation, but in practice, the popularity of the log data is low, so this method cannot be widely used

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