【作者】 刘建新；

【导师】 任韶然；

【作者基本信息】 中国石油大学 ， 油气井工程， 2009， 博士

【摘要】 油气井高产水是油田注水开发后期遇到的主要问题之一。油气井产水有许多危害,如降低原油采收率,增加地面原油脱水费用和水处理费用,加剧管线和设备的结垢和腐蚀,甚至导致关井停产,严重影响了油田的正常生产。相关学者提出了许多油气井堵水技术来控制油气井的产水量。常规的化学堵水技术在堵塞地层水道的同时,也会堵塞油流通道,使油井产油量下降,影响经济效益。而相对渗透率改善剂可笼统注入油气井,对水相渗透率的降低程度远大于对油相渗透率的降低程度,具有控水不堵油的特点。相对渗透率改善剂控水技术施工方便,具有低成本、低风险、低的环境伤害等优点,有广阔的应用前景。本论文研究两种类型的相对渗透率改善剂,一是超分子阳离子聚合物,二是两性聚合物/柠檬酸铝胶态分散凝胶。通过岩心流动实验,根据测试的残余阻力系数的大小,筛选出超分子阳离子聚合物MA303作为相对渗透率改善剂。MA303溶液配制方便,在岩心的注入性能好,耐冲刷性能好,可耐温90℃,耐矿化度50000mg/L,具有优秀的控水不堵油效果。本论文提出将胶态分散凝胶作为相对渗透率改善剂用于油气井控水的方法,该方法比使用聚合物控水的效果要好。制备了两性聚合物/柠檬酸铝胶态分散凝胶,通过粘度法、微孔滤膜法和扫描电镜法等实验手段研究了胶态分散凝胶的交联反应影响因素和交联机理。胶态分散凝胶是聚合物分子上的羧基与柠檬酸铝的配位交联反应形成的,是由分子内交联为主,相互连接较弱的凝胶小颗粒组成的分散体系,其交联反应受聚合物浓度、聚交比、温度、矿化度、pH值等因素的影响。通过岩心流动实验研究了胶态分散凝胶的控水性能,胶态分散凝胶在岩心的注入性能好,具有优秀的选择性控水效果和耐冲刷性能。相对渗透率改善剂在地层的吸附对其控水效果至关重要。本文采用淀粉-碘化镉法测量MA303溶液的浓度,测定了MA303在不同条件下的静态吸附量,研究了MA303的静态吸附机理和影响因素。通过岩心流动实验研究了MA303在多孔介质中的水动力学吸附机理和选择性控水机理。结果表明,静态吸附主要受聚合物种类、聚合物浓度、吸附时间、岩石颗粒成分和表面性质等因素的影响。动态吸附主要受静电引力和水动力的影响,在低的聚合物注速时,静电引力起主导作用;而在较高注速时,水动力起主导作用。聚合物注入速度增加,吸附层厚度呈线性增加。盐水注入速度(后置液)对吸附层厚度也有一定影响,吸附层厚度随盐水注速增加而增加。提高聚合物溶液和后置盐水溶液的注入速度,有利于改善地层岩石的聚合物吸附能力,提高堵水效果。相对渗透率改善剂的选择性控水机理是膨胀/收缩机理和油水分流机理。针对油田堵水作业成功率低的问题,本文研究了相对渗透率改善剂控水作业的地层适应性、选井原则和施工方法。在孤东油田进行了油井的相对渗透率改善剂控水作业,作业后油井产水率平均降低了6.6%,投入产出比1:3.9。针对我国目前老油田普遍的的油井结垢和高产水情况,提出了相对渗透率改善剂油井控水与挤注防垢复合技术。该技术具有控水和防垢的双重作用,同时节省施工成本。通过配伍性实验、静态防垢率实验、动态最低有效浓度实验和岩心流动实验筛选出合适的防垢剂,对防垢剂和相对渗透率改善剂复配体系的控水防垢性能进行了研究。实验结果表明,防垢剂SA13和相对渗透率改善剂MA303复配的防垢性能最好。更多还原

【Abstract】 Water production from oil and gas wells is a serious problem for the oil industry. Water production causes several problems to oil wells such as reducing well productivity, increasing the operating costs of separation and the disposal of produced water. It also promotes scale and corrosion of tubular and equipments, causing premature well abandonment, and having a great effect on oil production and transportation. Many water shutoff technologies have been proposed for this problem. Conventional water shutoff technologies not only block the water channel, but also block oil passage, thus decrease the oil production, and affect the economic effect. An option that can be considered when conventional water shutoff agent cannot be applied is the injection of relative permeability modifier (RPM) that selectively reduce the permeability to water and not significantly restrict oil flow. The main advantages of RPM treatments are low cost, low risk and low environmental impact.Cationic polymers and colloidal dispersion gels (CDG) as PRM for water control were studied. Supermolecule cationic polymer MA303 was selected by residual resistance factor through core flooding experiments. Its water solubility and injectivity are suitable for down-hole application. It also has a good property for selective water control with temperature resistance at 90℃and salinity resistance of 50000mg/L.Using CDG as RPM for water control was presented. An amphoteric polymer/AlCit CDG was prepared. The mechanism and influential factor of crosslinking reaction of CDG were studied by several experiments such as viscosity method; microporous filter membrane method and SEM method, etc. The crosslinking reaction of CDG is intramolecular crosslinking, through forming coordination link between AlCit and carboxyl in polymer molecules. The property of selective water control using CDG was studied by core flooding experiments. Its injectivity is suitable for down-hole application. The CDG treatments as RPM for water control reduce permeability to water more than to oil, and its life is long.Adsorption of RPM on rock surface is important in water control by squeezing RPM in oil wells. The concentrations of supermolecule cationic polymer were measured by iodine-starch colorimetric method. The hydrodynamic adsorption and the mechanism of water control were studied by coreflooding experiments. Experimental results show that adsorption of cationic polymers in porous media is affected mainly by electrostatic attraction and hydrodynamic forces. At low polymer injection rates, polymer adsorption is dominated by electrostatic forces, while it is dominated by hydrodynamic forces at polymer injection rates. The adsorbed layer thickness increases linearly with polymer injection rates. The adsorbed layer thickness is also affected by the brine injection rates in back-flush: high brine injection rate can increase the adsorption. Therefore, the adsorption of polymers can be improved using higher rates in squeezing both polymer and back-flush brine solutions, and so the water control efficiency. The mechanism of water control of RPM includes swelling/shrinking effect and segregated flow effect.Where RPM treatments can be successfully applied and candidate selection rules for RPM treatments were analyzed. The RPM treatment is simple to operate, and has been successfully applied in oil well in Gudong oilfield with a water cut decrease of 6.6% and a input output ratio of 1:3.9.In order to controlling scaling and water production, a combined technique of RPM treatment and scale inhibitor squeeze treatment in oil wells is presented, which achieves both water control and scale control purposes and saves treatment cost. The scale inhibitors combined with RPM have been selected based on laboratory experiments, including compatible tests, scale inhibition efficiency and minimum inhibitor concentration experiments and core flooding experiments. The results demonstrated that the combination of SA13 and MA303 is satisfactory for both scale and water control.更多还原