“堵水+调剖”联合作业效果及液流转向机理研究——以渤海SZ36-1油藏地质和流体条件为例

Study on the Effect of "Water Shut-off and Profile Control" Combined Operation and Liquid Diverting Mechanism:A Case Study of SZ36-1 Reservoirs in Bohai Oilfield

由于SZ36-1油田具有储层胶结疏松、非均质性严重、平均渗透率较高、原油黏度较高和单井注水量较大等特点,亟待采取液流转向措施以达到稳油控水的效果。以SZ36-1油田实际储层地质和流体为研究对象,通过室内物理模拟实验的方法,开展了堵水(堵水剂为淀粉接枝共聚物)、调剖(调剖剂为Cr^(3+)聚合物凝胶)和"堵水+调剖"联合作业增油降水效果及其影响因素实验研究。结果表明,与单独堵水或调剖措施相比较,"调剖+堵水"联合作业增油降水效果较好。随堵水剂顶替液段塞尺寸增加,中低渗透层分流率增加,堵水增油降水效果提高,但采收率增幅呈现"先增后降"趋势,所以综合分析合理段塞尺寸为0.05 PV左右。除此之外,随储层原油黏度增加,水驱中低渗透层分流率减小,采收率降低;"堵水+调剖"措施后,注入压力升高幅度增加,中低渗透层分流率增加,但最终采收率仍然较低。

SZ36-1 Oilfield,characterized by loose reservoir,serious heterogeneity,high average permeability,high viscosity of crude oil and large amount of water injected in single well,is in an urgent to take the liquid diverting measures to achieve the effect of stabilizing oil production and controlling water cut.In order to meet the technical requirements of the oil reservoir management,the authors,taking SZ36-1 reservoirs in Bohai Oilfield as the object,studied the effect and influence factor of water shut-off（starch graft copolymer as the agent）,profile control（Cr3＋ Polymer gel as the agent） and ＂water shut-off and profile control＂ combined operation by indoor physical simulation.The results showed that the effect of ＂water shut-off and profile control＂ combined operation were better than that of individual water shut-off or profile control in increasing oil production and decreasing water cut.With the increase of liquid slug size replaced by the plugging agent,the split ratio of the reservoirs with low to middle permeability increased and the effect of increasing oil production and decreasing water cut increased.However,the recovery factor showed the trend of ＂first increasing and then dropping＂.Therefore,the reasonable slugging size is about 0.05 PV.Besides,with the increase of oil viscosity in the reservoir,the split ratio and recovery of the reservoir with low to middle permeability by water drive decreased;injection pressure and split ratio of the reservoir with low and middle permeability increased after taking the measures of water shut-off and profile control,but the final recovery still very low.