Abstract:

The conventional grid method is difficult to describe condensate gas reservoirs with thin oil ring. Based on the bedding grid and horizontal grid, mixed grid-modeling method was established by analyzing oil ring distribution and the existing reservoir simulation grid technique. The bedding grid was used to describe distribution of gas reservoirs, and the horizontal grid was used to describe distribution of oil rings. Both grids were effectively coupled into a mixed grid. In the mixed grid, the bedding grid was pinched out at the gas-oil contact surface and coupled with the horizontal grid in geometric shape. The non-adjacent grid conductivity model was used to calculate the flow transmissibility coefficient of fluid flow from the horizontal grid to the bedding grid. The mixed grid method could avoid limitations of bedding grid for describing distribution of oil ring with zigzag, decline the grid number in description of oil ring and enhance calculating velocity in numerical simulation. The dynamic development performance of thin oil ring and the characteristics of bottom water coning could be effectively simulated by this method, the simulated results are more reasonable.

Key words: condensate gas reservoir, thin oil ring distribution, bedding grid, horizontal grid, mixed grid, numerical simulation

摘要：

分析了薄油环分布特征及现有油藏模拟网格技术特点,引入顺层网格和水平网格,论述了混合网格建模方法。利用顺层网格描述气藏分布,用水平网格描述油环分布,并将两种网格有效地耦合到一个网格系统中。混合网格模型中顺层网格在油气界面处为水平尖灭,与水平网格重合,实现在几何形状上的耦合。采用非相邻网格传导系数模型计算从水平网格向顺层网格间的流体流动传导系数,实现流体流动的耦合。混合网格建立方法可以有效地避免顺层网格呈锯齿状描述油环的分布特点,减少描述油环分布的网格数量,提高数值模拟计算效率;也可有效地模拟薄油环开采动态特征及底水锥进薄油环动态过程,模拟结果更加合理。

关键词: 凝析气藏, 薄油环分布, 顺层网格, 水平网格, 混合网格, 数值模拟