苏北稠油油藏CO2复合吞吐用新型降黏剂合成及效果评价

Synthesis of a new viscosity reducer for CO2 compound huff and puff in North Jiangsu heavy oil reservoirs and its effectiveness evaluation

苏北油田兴北区块为极复杂断块稠油底水油藏,原油黏度大、流动性差导致开发矛盾突出。针对整装稠油油田的成熟开采方法难以实现该类油藏经济有效开发的问题,提出了底水稠油油藏CO2与降黏剂复合吞吐技术方法。降黏剂是该技术方法成功实施的关键。通过在降黏剂分子中引入苯环结构合成新型高分子表面活性剂型降黏剂,从浓度、温度、矿化度、pH值等方面开展该新型降黏剂性能评价。结果表明,该降黏剂具有较好的耐温抗盐性,降黏剂浓度为0.5%时,稠油降黏率达到了90%以上,该降黏剂与CO2混注条件下仍具有稳定的降黏率。矿场实施取得了较好的增油降水效果,对苏北油田及国内同类复杂断块稠油油田的经济有效开发具有较好的应用前景。

Xingbei block in North Jiangsu Oilfield is a complex fault block with heavy oil and bottom water reservoir.High viscosity and poor flowability of crude oil lead to low oil recovery.As it is difficult to realize the economical and effective development of this heavy oil reservoir by conventional technique,a method of combined stimulation of CO2 and viscosity reducer is proposed for EOR in heavy oil reservoir with bottom water.Viscosity reducer plays an important role in this method.A new polymer surface active agent for viscosity reduction is synthesized by introducing the benzene ring structure into viscosity reducer.The performance evaluation of this new viscosity reducers is carried out from the aspects of concentration,temperature,salinity and pH value.It shows that the viscosity reducer has good temperature resistance and salt tolerance.When the viscosity reducing agent concentration is 0.5%,the viscosity reducing rate of heavy oil reaches more than 90%.It also has a stable viscosity reducing ability mixing with CO2.Good effects of increasing oil production and reducing water cut have been achieved in the in-site implementation.There will be a promising prospect in the economic and effective development of North Jiangsu Oilfield and other similar domestic heavy oilfields with complicated fault block.