Visbreaking And Lifting Technology Research And Filed Application In Deep Heavy Oil Well

The heavy oil reservoir of middle depth of Lukeqin oilfield has characters including high viscosity,much difference of permeability among layers,difficult extraction,loose layers and so on.The water cut rise up with the efficient production into high water content in fluid.The volume of thin oil mixed with heavy oil has increased while some new questions encounter such as hard lifting,sTab.emulsification,which need to be solved in new approaches.The paper aimed at proposing new ways according to the factual problems.The contents including domestic chemical ways survey for viscosity decrease;formulating research,chemical techniques used downhole,ground demulsification,artificial lifting optimization,the details as following.The formulating research:based on the mechanism research,investigating the similar domestic oilfields used chemical methods in application,combined with reservoir features and fluid properties,we did much job in laboratory about selection of prescription,evaluation,and integral combination,at last,we got the suiTab.viscosity breaking agent:CFS-I and CFS-Ⅱ;the latter has resistance of calcium or magnesium ions concentration 11000 mg/1,temperature 85℃,emulsions keep stability more than 0.5 hours.Viscosity breaking techniques:we have formed the best way for lowering the viscosity of heavy oil and lift on the ground smoothly by optimizing the equipments,lifting parameters,injection style,swabbing rod design,pump parameters and mixing location;Ground demulsification:through much investigation on domestic demulsified agent,we come up with the main agent of polyether which was processed by some degree of grafting,modification.It works among the 60-80℃,100-300mg/l,and Dehydration rate of 95%above.By carrying out the research about 0/W type demulsification,we have solved the matching relation between emulsified and demulsified oil,and selected demulsifier GC-1 which has a quick breaking speed,clear water after dehydration,and neat oil and water interface;we also defined the best added amount of 200mg/l at the temperature of 60℃.At the same time,we conduct the optimization of ground matched process flow and equipment,and the demulsifier could meet our need in Lukeqin reservoir.The artificial lift optimization:we conduct the working condition analysis of pumping unit,in order to understand the oil production capacity,the working condition of equipment,to further draw up rational technical measures;through ground parameters adjustment and sensitivity analysis of lifting efficiency and economic benefit on the fixed tube pumping wells.Taking high efficiency as goal,laying down the adjustment program,predicting production and equipment working index after optimization.For new wells or workover wells,through optimizing design,coming up with the rational lifting style(mixing chemicals in hollow of rod or space of casing)which including production parameters and hardware conFig.uration(such as pumping unit,pump type,pump diameter,stroke,lifting frequency,pump depth,and the pump sucker rod column combination,centralizer installation location,adding weight stem length,specifications,etc),based on these optimization job,we could predict the swabbing parameters and operating mode such as loading,stress,torque,power,efficiency,yield,pump efficiency and its integral analysis,etc.In short,the paper embodies the good innovation and got a lot of research fruit.The innovations including four aspects.The first is concept innovation,which apply the reducing friction thought to the research process of chemical prescription.The second is idea innovation,which used new methods of adjusting proportion value between hydrophilic group and lipophilic group of molecular structure of viscosity reducing agent.The third is structure innovation,which introduce the organic silicon molecular chain and amount to the viscosity reducing agent.The fourth is technique innovation,which apply the centralized fluid mixing method,volume controlling total liquid concentration,water and oil ratio in wellbore,and fluid velocity to the research process of viscosity breaking techniques.The third innovation reached the leading level domestic.The main achievements solved the problems of heavy oil reservoir development during the stage of high water cut,high mixing ratio,and lowering the cost of production.The viscosity breaking technology became a new approaches and established a technology base for future heavy oil production efficiently.The integral techniques also provided strong technical support for oil increasing and sustainable development for oilfield.