无机凝胶在高盐油藏的调驱效果及工艺参数优化——以吐哈雁木西油田为例

Effect of Inorganic Gel Flooding and Parameters Optimization in High Salt Reservoir——Take Yanmuxi Oilfield of Tuha as an Example

吐哈雁木西油田为高盐中低渗透油藏,目前已经进入特高含水率开发阶段。为满足该油田提高采收率技术需求,本文以雁木西油田储层地质特征和流体性质为模拟对象,开展了高盐油藏无机凝胶调驱效果及工艺参数优化实验研究。研究结果表明,在矿化度为151453 mg/L、岩心渗透率为800×10^-3/200×10^-3/50×10^-3μm^2条件下,当主剂(0.03 mol/L的硅酸钠溶液)段塞尺寸为0.06数0.08 PV和注入轮次为5数6时,岩心中低渗透层的动用程度较高,含水率下降约10%,采收率增幅在10%以上。在主剂用量相同条件下,与各轮次药剂采用“等浓度”注入方式相比,采用“递增”注入方式深部液流转向效果较好,采收率增幅增大1.53%。与无机凝胶或Cr^3+聚合物凝胶相比较,“无机凝胶+表面活性剂”或“Cr^3+聚合物凝胶+表面活性剂”调驱波及区域洗油效率较高,最终采收率增幅增加4%左右,但“产出/投入”比值较小。与无机凝胶相比较,Cr^3+聚合物凝胶调驱采收率增幅较大,但由于聚合物溶液配制和注入工艺比较复杂,技术经济效果较差。

Yanmuxi Oilfield of Tuha,a high salinity,medium and low permeability reservoir,has entered the stage of ultra-high water cut development.In order to meet the technical requirements of enhancing oil recovery of oilfield,the experimental study on the effect of inorganic gel flooding and parameter optimization in high salinity reservoir was carried out taking the geological characteristics and fluid properties of reservoir of Yanmuxi oilfield as simulation objects.The results showed that when the salinity was 151453 mg/L,the core permeability of high/middle/low permeability layer was 800×10^-3/200×10^-3/50×10^-3μm^2,the slug size of the main agent,0.03 mol/L sodium silicate solution,was 0.06—0.08 PV and the injection cycle was 5—6,the utilization degree of the low/medium permeability layer in the core was higher,the water cut decreased by 10%and the oil recovery increased by above 10%.Under the condition of the same amount of main agent,compared with the"equal concentration"injection method for each round of reagents,the“incremental injection”method had better effect on the deep fluid diversion and the recovery rate increased by 1.53%.Compared with"inorganic gel"or"Cr^3+polymer gel","inorganic gel+surfactant"or"Cr^3+polymer gel+surfactant"had higher efficiency of oil displacement in sweep area of profile control and flooding,and the final recovery rate increased by about 4%,however,the"output/input"ratio was smaller.Compared with the"inorganic gel",the"Cr^3+polymer gel"had a larger increase in the recovery rate of the polymer flooding,but the preparation and injection process of the polymer solution was more complex and the technical and economic effect was poor.