The Optimum Design Of Heavy Oil Shaft Lifting In Deep Well

At present,the reserves of world’s heavy oil and super heavy oil and natural bitumen are approximately1000×108t and is very impressive.As the huge amount of resources,the oil-producing countries of the world are paying more and more attention. With the passage of time,the amount of resources are being less and less,the development of heavy oil must be a very important part of the oil industry.Heavy oil and bitumen resources of our country are widely distributed and have een found more than70heavy oil fields in12basins, accounting for30%of the total (?)il reserves.So it may be the major challenge to the China’s petroleum staff that how to (?)ine these heavy oil resources economicly and effectivelyThough the Tahe reservoir oil is heavier (the Viscosity ranges from595mpa.s to (?)0×104mPa.s at50℃), it still has some flow property and better oil supply capacity it has higher temperature under reservoir conditions and can flow to (?) wellbore depths of2000-3000m.But during flowing in the wellbore, its viscosity (?)omes heavier and heavier because of the and may lose the flow property because of (?)he reducing of the temperatue caused by the wellbore heat loss.So the wells could not maintain production, the present exploitation amount far failed to give full play to the potential of heavy oil.It has high depth, high viscosity and high salinity in Tahe filed. Based on the characteristics, this paper gives full analysis of the viscosiy-temperature data,production data and filed technology and builts the calculation models suitable for the Tahe filed,such as the viscosiy-temperature model, the wellbore temperature field model, the wellbore viscosity field model and the wellbore pressures model.We also creating a Shaft Lifting Optimum Design system which we can use to provide a reference to the actual production of the oilfield.As the crude oil has highl depth and high viscosity in Tahe block,it is not well to be lifted to the surface,so how can more accurately determine the wellbore oil viscosity distribution is particularly important.Based on full analysis of Tahe viscosity-temperature experimental data, we find that viscosity-temperature data of the different wells in the same block vary greatly,even in the same well at different times they are also quite different. So we built viscosity-temperature database of the Tahe block wells to deal it.Considering the conditions of the viscosity reduction process,we establish a wellbore temperature distribution model,basing on the heat transfer theory and putting the single well as the object of study.Then combining with the viscosity-temperature data,we establish the wellbore viscosity field.The same time,by surveying domestic and foreign research on multiphase flow calculation model,we built the wellbore pressure distribution model.The production effect of steam stimulation directly depends on various ieservior factors. For example,skin factor, reservoir depth, reservoir permeability, Crude oil viscosity etc. In addition to the reservoir factor, level steam injection string structure is also important factors during influencing reservoir suck steam profile.Beearse the string steam injection flow resistance and inhomogeneity of the reservoir petmeability;the steam and liquid with injecting reservoir is generally uneven,which can cause premature coning or steam breakthrough within a reservoir, dioping energy d(?)cy,flooding swept area reduction, influencing horizontal recovery.Therefore it has important meaning for developing heavy oil efficiently through selecting tlnese parameters and designing good steam injection string structure.At present the horizonial wells had been widely used in gas reservoirs o(?) bottom water,or big obliquity reservious or (?) feactured reservol development,(?). The heavy o(?) reservoirs of Sheng Li (?) water,after the reservoirs high round throug(?) strata defi(?) bottom water invasio(?) intensified,researvoir water flooded seriou(?) influence steam injectior development effect. So I’m order to realize the horizontal (?) even steam injection,for injection parameters (?) of (?) GuDong blbcks of the oilfield, increased direct contact area between we(?) and the reservoirr,and provided favorable conditions for the oil into the well(?) for heavy (?) or heavy oil reservior,(?)zontal wells can greatly improve the steam injection,increased the rangeof heat reservair and (?)(?) the pressure distribution model using the actual parameters,we find that it has good accuracy and it can provide the foundation for the next shaft lifting cptimization design,The sucker-rod pumping system is made up of the oil layer,the borehole and ground equipment. In order to keep this system worked efficiently, three subsystems must work in accordance. But the wells are of high depth and the crude oil is of high viscosity in Tahe filed,, fluid in borehole cause heavy friction losses, which reducing the system stability. Meanwhile, With the variety of reservoir pressure, GOR and water cut, the sucker-rod system don’t work in accordance. The low efficient wells need be redesigned to improve the system stability and make it work efficiently.In the pumping system optimization design, we determine he pumping unit, the rod string and the pump the basing on the oil production and pumping-setting depth. Considering the influence of the dynamic character of the pumping unit, the rod string and the pump and the accordance between the oil layer and the production system, we establish the economic index as a system optimization design objective function。Then using the function to determine the reasonable system and ensure that the system to meet the production requirements in the premise, and have higher working efficiency. This paper mainly uses two methods:load superposition method and improved API method. AS the results of the two methods of design are the same as the practical wells’s, it will bring about the comprehensive treatment, and stable oil production has the very vital significance.