考虑隔夹层影响的平行水平井网三维水驱油实验及驱替特征研究

Study on Displacement Characteristics of 3-D Water Flooding Experiment of Parallel Horizontal Well Pattern Considering the Effect of Interlayer

以相似理论为指导,根据渤海BZ油田目的层地质条件设计了具有不同封隔能力的50 cm×50 cm×30 cm(长×宽×高)非均质性三维储层模型,井网选择平行水平井网。在优选的1.0 mL/min的驱替速度条件下,采用平行水平井网进行2组水驱油实验,通过测量驱油过程中储层的电性特征、注入水、采油量和产水量等参数,将储层的电性特征换算成含油性,分析在具不同特征的储层中水驱特征。结果表明:平行水平井网在具不同夹层类型模型水驱油过程中,注入水在重力和不渗透夹层的遮挡作用下使得注入水在储层下部注采跟部区域突进更快、见水更早、波及范围小、总体采出程度低,在模型上部夹层之上区域剩余油饱和度高。对于具不渗透夹层的储层类型可以通过在夹层上方加密井网来提高采收率。对于具半渗透夹层的储层类型的储层剩余油的挖潜重点在夹层下部未受注采井控制的区域。

Guided by the similarity theory,according to the geological conditions of BZ oilfield in Bohai Sea,a three-dimensional reservoir model of 50 cm×50 cm×30 cm(length×width×height)with different sealing capacity is designed.The well pattern is parallel horizontal well pattern.In the model,interlayer is set at 1/2 of the separation well above the water injection well.There are two characteristics:one is impermeable;the other is certain The permeability of semi permeable interlayer is 800mD.Under the optimal displacement rate of 1.0 mL/min,two groups of water displacement experiments were carried out by using parallel horizontal well pattern.The electrical characteristics of the reservoir,injection water,oil production and water production were measured during the process of oil displacement,and then the electrical characteristics of the reservoir were converted into oil-bearing property.Finally,the water flooding characteristics of the reservoirs with different characteristics were analyzed.The results show that in the process of water flooding in the model with different interlayer types in parallel horizontal well pattern,under the shielding effect of gravity and impermeable interlayer,the injected water inrush faster in the injection production heel area of the lower reservoir,earlier water breakthrough,small sweep range,low overall recovery degree,and high residual oil saturation in the area above the upper interlayer of the model.For the reservoir type with impermeable interlayer,oil recovery can be enhanced by infilling well pattern above the interlayer.For the reservoir type with semi permeable interlayer,the potential tapping of remaining oil is focused on the area which is not controlled by injection and production wells in the lower part of the interlayer.