一种优化楔形带有效厚度计算的新方法

NEW OPTIMAL CALCULATING METHOD OF THE NET PAY IN THE WEDGE BELT

通过数值模拟等方法,探讨了勘探阶段常用的有效厚度评价方法在"楔形带"存在的误差范围及倾向。研究认为:"固定系数法"的误差存在于整个楔形带,误差数值大小取决于楔形带砂地比、净毛比及地层厚度变化的综合效应,误差倾向无确定性;"聚类平移法"的误差分布范围取决于纵向由上至下第一层砂体净毛比,误差数值大小取决于砂泥岩叠置次序,一般会导致计算结果偏大。提出了可以规避前两种方法产生误差的有效厚度评价新方法——"单层控制逐层累加法",能够为油气藏早期评价中有效厚度分布的求取及地质储量的计算提供可靠依据。

By means of the numerical simulation etc., the error range and tendency in the wedge belt are expiorea and discussed by the net-pay evaluating method which is commonly used in the exploration stage. The studies show that for ＂Fixed Coefficient Method＂, the error is present in the whole wedge belt, and the error range is depending on the combined effects of the changes of sand-formation and net-to-gross ratios, and moreover the stratigraphic thickness of the wedge belt, the error tendency is uncertain ; for ＂Clustering-Translation Method＂, the distribution range of the error is depending on the net-to-gross ratio of the first sandstone layer lengthwise from top to bottom and the error value is determined by the stacked sequence of the sandstone and mudstone, and results. In view of this, a new method named as ＂Individual-layer ControUing and Accum this will cause serious ulating to avoid the errors which are generated in the two methods stated above, thus Layer by Layer the reliable bases for the net-pay distribution calculation and geological reserves estimation in the early petroleum evaluation stage can be provided.