低渗稠油油藏蒸汽吞吐合理开发井距的确定——以叙利亚O油田为例

Determination of reasonable well spacing for low-permeability heavy-oil reservoirs by steam huff and puff:taking O oilfield in Syria for example

以叙利亚O油田SH_B油藏为例,研究了低渗稠油油藏蒸汽吞吐开采时考虑变启动压力梯度影响的有效动用范围和合理开发井距。首先采用驱替实验测定不同渗透率、不同原油黏度条件下油相的启动压力梯度,确定启动压力梯度与流度呈幂函数关系;然后基于水平井焖井结束后,开井生产时的水平井沿程温度变化和建立的黏温关系,首次揭示了水平井沿程的变启动压力梯度分布特征。在此基础上,建立考虑变启动压力梯度的数值模型,通过数值模拟,研究低渗稠油油藏蒸汽吞吐开采时考虑变启动压力梯度的油藏有效动用范围,论证了油藏合理开发井距,为O油田SH_B油藏蒸汽吞吐开发方案编制提供了依据。

Taking the SH_B oil reservoir in O oilfield in Syria for example,the effect of variable starting pressure gradient on the effective producing radius and the rational well spacing in low permeability heavy oil reservoirs is studied.First,the starting pressure gradients of oil phase under different permeability and different oil viscosity were measured by core flooding experiments.The experimental results show that the starting pressure gradient has a power function relationship with the mobility.Then,based on the temperature calculation of horizontal well during producing after soaking and the relationship between the viscosity and temperature,for the first time,the starting pressure gradients at different positions of the wellbore are determined.On this basis,a numerical model considering the variable starting pressure gradient was established.The influence of the starting pressure gradient on the effective producing radius and the reasonable well spacing of the low permeability heavy oil reservoir was studied through numerical simulation,which provides the basis for designing the CSS development plan of SH_B reservoir,O oilfield.