|
||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Uncertainty analysis of reserves of fluvial reservoir calculated by geological model
Reservoir Evaluation and Development
2018, 8 (4):
1-5.
DOI:
The reserves of the geological model in the offshore fluvial reservoirs are influenced by the uncertain parameters, such as the structure, plane variogram, correlation between reservoir properties and seismic attributes, irreducible water saturation, lower limiting value of effective reservoir, volume coefficient, and oil-water interface. The root that causes these uncertain parameters is analyzed. Meanwhile, taking oilfield-Q in Bohai bay as an example, and by the integrated application of the Monte-Carlo method and stochastic modeling, the effects of the uncertainty parameters on the reserves are estimated quantitatively. The probability cumulative distribution curves of reserves and 3 probability reserve value which are the pessimistic reserves（P90）, expected reserves（P50） and optimistic reserves（P10） are obtained to predict the risk and potential of the reserves.
Table 1
Uncertainty variable values of certain sand body
Extracts from the Article
渤海Q油田是在潜山披覆构造背景上形成并被断裂复杂化的,受岩性和构造双重因素控制的大型油田。该油田构造幅度比较平缓,主要含油层系发育于新近系明化镇组（Nm）下段,为曲流河沉积。该油田有钻井200多口,综合含水90 %,处于油田开发的中后期,储层的构造比较落实。本文选取了该油田10个主力砂体进行不确定性分析。通过研究和分析认为,该油田在地质建模过程中,影响储量的不确定性变量主要有以下6个,即平面变差函数、沉积微相百分含量、有效储层下限值、体积系数、油水界面和束缚水饱和度。表1为其中一个主力砂体的不确定性变量取值,取值方法如下：1） 通过建模软件的数据分析功能和沉积微相平面分布,可以得到不同沉积微相的P10、P50、P90的变差函数和百分含量;2） 有效储层下限和体积系数已经在前文就该油田进行了分析,在此不做赘述;3） 过路井钻遇该砂体的油底和水顶的分布范围在-1 150~-1 146 m,综合取值为-1 148 m,为了评价油水界面存在的风险,建模时油水界面取值范围为-1 150~-1 146 m;4） 应用离心法对该油田岩心样品进行束缚水饱和度测试,得到束缚水饱和度为0.18~0.3,平均0.25,为了评价束缚水饱和度的不确定性,建模时取值为0.18~0.3。
Other Images/Table from this Article
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||
