镇北油田高碳蜡原油采输清防蜡实验研究

Experimental Study on Paraffin Removal and Control during Production and Transportation of Crude Oil with High Carbon and Paraffin in Zhenbei Oilfield

为有效抑制高碳蜡原油井筒内壁蜡沉积,确保采输过程安全高效,以镇北侏罗系高碳蜡区块为研究对象,对油样析蜡点、SARA组分、蜡样熔点及碳数进行分析,评价现有清蜡剂的适应性,优选耐高温、耐高矿化度微生物嗜蜡菌,研制新型固体防蜡剂并进行现场试验。结果表明:侏罗系高碳蜡原油凝点高、胶质沥青质含量低,蜡样均为饱和烃,碳数在C_(25)以上,属高碳微晶蜡,易形成稳固三维结构而发生严重蜡沉积;其CX-3清蜡剂溶蜡速率为0.91 g/min,效果最优且适用多数区块;嗜蜡菌对原油的凝固点和含蜡量均有降低作用,且对润湿性也有较显著影响;新型固体防蜡剂合成正交试验的加量为0.5%时,防/溶蜡剂A、B、C质量比为8∶1∶1,其防蜡率最高,可达88.31%,现场试验表明清防蜡效果显著。在同类结蜡井中具有推广应用价值。

In order to effectively inhibit the wax deposition of the crude oil with high carbon and high paraffin on the inner wall of wellbore,to ensure the safe and efficient production and transportation process,taking the Jurassic high carbon and paraffin block of Zhenbei Oilfield as the research objective,the wax precipitation point,SARA composition,waxmelting point and carbon number of oil sampleswere analyzed,andthe adaptability of the existing paraffininhibitors was evaluated.A new solid paraffin inhibitor is developed using paraffin degrading bacteriawith high temperature and high salinity resistance.The experimental results show that the Jurassic oil samples have high pour point and low content of colloidal asphaltene.The paraffin samples are saturated hydrocarbons with carbon number more than C25.They belong to high-carbon microcrystalline waxes,which are easy to form a stable three-dimensional structure and cause serious wax deposition.The wax dissolving rate of paraffininhibitor CX-3 is 0.91 g/min,the wax dissolving effectof it is the best and it is suitable to most blocks.The paraffin degrading bacteriacan reduce the pour point and paraffin content of crude oil,and has a significant impact on the wettability of the crude oil.Orthogonal experiments show thatthe new solid paraffin inhibitoris of the highestparaffin inhibition rate of 88.31%when the mass fractionof it is 0.5%and the mass ratio of paraffin inhibitors A,B,and C is 8∶1∶1.Field test shows that the paraffininhibitor has significant paraffin control effect,and it can be applied to similar wax deposition wells.