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油层伤害对岩性油藏流动单元的影响——以鄂尔多斯盆地华池油田、马岭油田为例
The Impact of Formation Damage Upon Flow Units in Lithologic Pinchout Oil and Gas Accumulation with Reference to Huachi and Maling Oilfield in Ordos Basin
【作者】 朱玉双;
【导师】 柳益群;
【作者基本信息】 西北大学 , 矿物学、岩石学、矿床学, 2004, 博士
【摘要】 本文以鄂尔多斯盆地华池油田、马岭油田为例,运用沉积学、储层地质学、矿物学、开发地质学、油藏工程学、油田化学等多学科的理论、方法和技术,采用微观和宏观相结合、动态和静态相结合、理论和生产实践相结合的办法,针对岩性油气藏的特点,研究了油层伤害对储层流动单元的影响。建立了研究区的储层流动单元模型,对储层伤害进行了实验评价,得出了油层伤害对储层渗流特征及流动单元的影响。该研究的主要认识和创新点在于: 1、首次利用真实砂岩微观孔隙模型进行了流动单元的渗流机理研究,并利用真实砂岩微观孔隙模型流动实验对流动单元的划分结果进行验证,使所建立的流动单元模型更为可信。 2、多类别流动单元模型并联实验表明,相同类别的流动单元表现了相似的吸水和产液状况,不同类别的流动单元之间吸水和产液状况有着明显的差异。并且随着水驱油的进行,不同流动单元之间的吸水和产液状况差距很快加大。表明了流动单元在宏观上对流体的流动起着明显的控制作用。 3、油井的见效见水与注采井间流动单元的对接类型关系密切,注采井间为同类流动单元对接时,油井一般表现为见效快见水慢的特征:注采井间为不同类别流动单元对接时,油井一般表现为见效慢见水快的特征。 4、马岭油田木钵区块延10油层存在弱速敏,并且岩石的渗透率不同,临界流速也不同,一般岩石的渗透率越低,临界流速也越低,反之越高:木钵延10油层存在弱到中等水敏,并且注入流体矿化度越低,水敏伤害越强。逐渐降低注入水的矿化度会减轻水敏造成储层伤害的程度,最终注入水的最佳矿化度范围为2—5g/1。 5、华池油田长3储层结垢对储层的渗透率影响较大,影响程度与注入水和地层水在储层中的接触混合次数有关,混合次数越多,储层渗透率降低幅度越大,因此长3储层的高渗层、裂缝及近井底地带结垢堵塞将应较严重。 6、首次利用真实砂岩微观孔隙模型,研究了油层伤害条件下的渗流特征(油层伤害以结垢伤害和水敏伤害为例),研究结果表明,油层伤害条件下水驱油的入口压力增加,水驱油的微观绕流加重,簇状油块加大,驱油效率降低,水驱油的宏观波及系数也降低,从而降低了油层采收率。
【Abstract】 Based on the theory and methods of sedimentology, reservoir geology, mineralogy, exploitation geology, reservoir engineering and reservoir chemistry, the impact on flow unit of formation damage was studied in lithologic pinchout oil reservoir, taking Huachi Oilfied And Maling Oilfield As examples. The micro and macro, dynamic and static, and theory and practice were combined in the study. In the study the flow unit model was set up, the evaluation of formation damage was done, the displacement characters of oil by water under the reservoir injury were obtained, and the infection to flow unit was discussed. The mainly fruits are as follows:1.It is the fist time that the flow unit’s seepage mechanism were studied with natural sandstone micromodels, and the flow unit that has been plot out was validated using seepage experiment with natural sandstone micromodels for the first time. The flow unit model should be close the true by the study method.2.The experiment of combined natural sandstone micromodles indicate that the condition of the water absorption and liquid production are similar when the flow units are same, the condition will be difference obviously when the flow units are different, and the difference will be increase as advancing of experiment. It represents that flow units not only in micro but also in macro control the flow characters.3.The waterflooding response of oil wells are relate closely to the abutment manner between the oil well and water injection well. When the flow units are same between the oil well and water injection well, the responding of oil well will come soon, and water breakthrough will come late. When the flow units are different between the oil well and water injection well, the responding of oil well will come late, and water breakthrough will come soon.4.The velocity sensitivity is weak in Mubo Yan 10 reservoir, moreover the critical speed is related to permeability, and the critical speed is generally low when the permeability is low. In fact, the velocity-sensitive injury in waterflooding will be stronger than the results of experiments for the salinity of injected water being higher in experiment than in practice, the water sensitivity is weak to middle, and the extent of water sensitive damage will be reduced when water salinity is increased. According to the experiments the extent of water sensitive damage will be reduced when the water salinity is increased gradually and the suitable salinity of injected water is 5-10g/l.5.Scale deposit affects permeability largely in Huachi Chang3 reservoir. The infection extent is relate to the commixed times of injected water and formation water, the more commixed times of injected water and formation water, the more falling extent of permeability. It represents that the scale deposit will be seriously in the layer with high permeability, fracture and the area near oil well bottom.6.The study were done for the first time by using natural sandstone micromodles under formation injury. The research represents that the entrance pressure will increased, the heterogeneity of pore structure will become stronger, the injected water will make bigger detours, and the sweep efficiency in micro and macro will decreased under reservoir injury, as the results the reservoir recovery efficiency is reduced.
【Key words】 Ordos Basin; lithologic pinchout oil and gas accumulation; formation damage; flow unit; remaining oil; recovery efficiency;