基于SGR算法的断层侧向封闭性评价方法改进及其应用

利用Yielding断层侧向封闭性评价方法预测油柱高度过程中,发现断层侧向封闭油气能力与油气分布呈现部分不吻合现象,经过深入研究表明:是由于未考虑断层侧向封闭油气下限以及封闭区域造成的。当断面上某一深度范围内最小断层泥化率(SGR值)大于断层侧向封闭油气下限时,整条断层在该深度范围内对油气具有侧向封闭能力,Yielding断层侧向评价方法可直接应用,其预测结果与油气吻合度较好;而当断面上某一深度范围内最小SGR值小于断层侧向封闭油气下限时,该点在封闭区域之外,按照Yielding预测方法可能会低估或高估断层的侧向封闭能力。为了更准确研究断层侧向封闭性评价方法,因此针对这种情况对断层侧向封闭评价方法进行了改进,并选取冀中坳陷文安斜坡断层型圈闭为例,利用改进后的断层侧向评价方法对断圈侧向封闭能力进行定量评价,结果表明:沙一段1~2号断圈的预测结果与井含油气性相吻合,表明该方法用于定量评价断层侧向封闭性是可行的,更正了Yielding评价方法低估或高估封闭断圈侧向封闭油气的能力,提高了断层侧向封闭能力预测的准确度。

SGR Algorithm-Based Improvement of Fault Lateral Sealing Evaluation Method and Its Application

Generally, fault sealing is evaluated by the method of Yielding. In the evaluation process, we find lateral sealing ability of fault and distribution of oil that show some inconsistencies. Careful studies have shown that this phenomenon is due to not considering lateral sealing the lower limit and seal area of fault. When the minimum SGR is greater than the lower limit of fault lateral sealing on a certain depth range of fault plane, fault can seal hydrocarbon in this depth range, the fault lateral evaluation method of Yielding can be applied directly. However, when the minimum SGR is less than the lower limit of fault lateral sealing hydrocarbon on a certain depth range of fault plane, this point outside the seal area, according to the prediction method of Yielding which may underestimate or overestimate the lateral seal ability of faults. In order to predict hydrocarbon column height more accurately, this article is based on fault lateral sealing evaluation method of Yielding, considering lateral sealing the lower limit and seal area of fault. This article selects Wenan Slope of JiZhong Depression as an example. Fault trap lateral sealing ability is evaluated by the improved method. The results show that predicting sealing hydrocarbon column height in no.1and no.2 fault traps, in conformity with the oil and gas distribution, this indicates that the improved method is feasible. Improving the prediction method of Yielding which may underestimate or overestimate the lateral seal ability of faults, and increased forecast accuracy on the lateral sealing ability of fault.