特高含水油田提高采收率方法筛选

发布时间：2018-09-15 19:31

【摘要】：经数十年注水开发,世界上很多老油田,已进入高含水、特高含水阶段。美国东德克萨斯油田、福特杰拉尔丁油田,俄罗斯库列绍夫油田等含水都已达97%,平均采出程度大于50%,东德克萨斯油田采出程度甚至达到了77.5%。中国很多油田,也是先后进入特高含水期,即,含水达90%以上,尤其是大庆、胜利、大港、中原、河南、江汉等地。对于注水开发油田,不同含水阶段,含水上升速度是不一样的。中低含水期,含水上升速度随含水上升增大,大于5%；中高含水期,含水达到80%以后,含水上升速度减缓,几乎稳定在1%以内。油田在进入特高含水开发阶段后,开发规律与中高含水期不同,井网也发生很大变化,砂岩油藏注水开发后期,挖潜对象发生变化,水动力学调整技术实施效果变差,难以适应地下油藏情况。特高含水期油藏,采油速度很低、耗水量比较大、剩余油尤其分散、井况逐渐恶化、开发效益降低等特点,但是,从动用储量以及年产量看,高含水老油田依旧是开发主体,它的年产油量和剩余可采储量,在全国占有非常重要的地位,而且,地下依然还有大量原油地质储量没有被开采出来,所以,特高含水油田采收率,是制约国家持续发展的重要经济因素,尤其是,在现有的经济技术条件下,它的采收率的提高,具有进一步提升的潜力。本文首先研究了国内外特高含水期油藏基本特点、国内外油藏概况,分析了特高含水期油藏剩余油分布特征,然后系统、全面概括了特高含水油田,继续水驱、聚合物驱、氮驱、注凝胶驱、水气交注驱、CO2驱等七种提高采收率技术方法的基本原理、发展情况、适合油藏,做了一个全面系统地整合。1)继续水驱,对于注水开发的特高含水油田,处于高采出阶段,仍残有大量剩余油,通过同井分层注水技术、注采系统调整技术、周期注水技术,可以大大改善开发效果,有效的提高采收率。2)氮驱,有很大潜力成为进一步提高采收率的重要接替技术。油田进入特高含水期后,层内纵向水淹情况差异巨大,水窜极为严重。在进一步提高开采效率过程中,如何在驱油同时,抑制注入水沿高渗透部位的突进,是很有必要要解决的。氮气泡沫驱替液,进入渗透率高含油饱和度低部位,封堵储层,也能被诱导进入渗透率低、含油饱和度高部位驱替原油。3)聚合物驱,作为提高原油采收率的方法之一,使注入流体粘度提高,改变了油水两相流度比,从而扩大波及体积。水驱油时,当水油流度比)1,水的流动能力比原油强,发生指进现象,波及系数低。加入聚合物后,降低了溶液渗入地层的能力,提高粘度,减缓了溶液流动。其次,水在油藏渗流部位流动阻力增加了,波及效率提高了。4)凝胶驱,即：聚合物溶液在一定条件下,形成的特殊、分散体系,是在常规聚合物驱基础上,发展起来的一种具驱替、调剖双重功效新型的驱油技术。它能大幅度改善流度比,缓解层间矛盾,从而提高采收率,具有较好应用前景。在一定压力下,调剖剂在地层孔道中,生成高分子有机凝胶,封堵了高渗透吸水层,使注入水转向,避免了“舌进”现象,注入水转向进入中、低渗透层,从而使吸水面比较均匀。5)水气交注驱,该技术,克服空气驱“气窜”缺点,将水驱和空气驱有机结合起来,向水驱后油层注气,降低水相渗透率,从而降低水的流度,缩小水油流度比差,扩大水的波及体积。该技术非常适合于低渗、非均质严重、大孔道油藏,可以解决很多技术难题：如我国中西部地区低渗、特低渗油田注水开发中,局部地区缺水、注水井注水难、生产井地层严重亏空、油井采出水对环境污染等等,还可以促进我国中西部油气资源高效开发。中原、吐哈、华北油田,都进行过现场水气交注、非混相驱实验,取得不错的效果。6)CO2驱油技术,满足特高含水油田提高采收率需求,还可解决C02封存问题,保护大气环境。该技术适用于常规油藏,可以明显提高低渗、特低渗透油藏采收率。C02在地层内溶于水后,水的粘度增加20%～30%,运移性能提高2-3倍；C02溶于油后,原油体积膨胀,粘度降低30%～80%,油水界面张力降低,有利于提高采油速度、洗油效率和收集残余油。一般,CO2驱提高采收率7%-15%,油井生产寿命延长15-20年。C02可从工业设施获得,如发电厂、化肥厂、水泥厂、化工厂、炼油厂、天然气加工厂等排放物中回收,一方面,减排温室气体,另一方面,增产油气。最后,结合实例：1) Kumkol South油田,分析其开发存在问题,优化开发方式、研究调剖堵水和聚驱可行性,得到最优化方案；2)SH7油田,根据其地质模型、流体模型,结合水驱、聚合物驱、交联聚合物驱的效果,进行对比,得出最佳组合方案；3)LN纯56块油田,根据其开发状况,提出了水井调剖、油井提液降压、氮气泡沫交替注、氮气水交替注进行方案设计,优选出最佳方案；4)河11沙二块油田,根据开发现状,研究了聚合物调剖、水气交替注入调剖可行性,以及聚合物与水气交替注入综合调剖研究,得出最优方案。
[Abstract]:After decades of waterflooding, many old oilfields in the world have entered the stage of high water cut and extra high water cut. The water cut of East Texas, Ford Geraldine, Koreshov oilfields in Russia has reached 97%, the average recovery degree is more than 50%, and the recovery degree of East Texas oilfields has even reached 77.5%. For water-flooded oilfields, the rising rate of water cut is different in different water-cut stages. In middle and low water-cut stages, the rising rate of water cut increases with water cut, more than 5%; in middle and high water-cut stages, after water cut reaches 80%. After the oilfield enters the stage of ultra-high water-cut development, the development law is different from that of medium-high water-cut stage, and the well pattern also changes greatly. In the later stage of water injection development, the potential tapping object changes, and the implementation effect of hydrodynamic adjustment technology becomes worse, which makes it difficult to adapt to the situation of underground reservoirs. In reservoirs, the recovery rate is very low, the water consumption is relatively large, the remaining oil is especially dispersed, the well condition is gradually deteriorating, the development benefit is reduced, etc. However, from the production reserves and annual production, the old oilfield with high water cut is still the main development body, its annual oil production and remaining recoverable reserves, occupy a very important position in the country, and there is still a large underground. Oil recovery is an important economic factor that restricts the sustainable development of the country. Especially, under the existing economic and technological conditions, the improvement of oil recovery has the potential to be further enhanced. The general situation of external reservoirs is analyzed, and the distribution characteristics of remaining oil in ultra-high water cut reservoirs are analyzed. Then, the basic principles and development of seven enhanced EOR technologies, such as water flooding, polymer flooding, nitrogen flooding, gel flooding, water gas injection flooding and CO2 flooding, are comprehensively summarized, and a comprehensive and systematic integration of.1 is carried out. Continuous water flooding can greatly improve the development effect and effectively enhance the recovery factor. 2) Nitrogen flooding has great potential to become an important connection for further enhanced oil recovery. After the oil field enters the extra high water cut stage, there is a great difference in the longitudinal flooding and the water channeling is very serious. In the process of further improving the mining efficiency, it is necessary to solve the problem of how to suppress the injection water to move along the high permeability part in the process of flooding. Polymer flooding, as one of the methods to improve oil recovery, can increase the viscosity of injected fluid, change the ratio of oil to water two-phase fluidity, thus expanding the sweep volume. When water to oil fluidity ratio is 1, the flow ability of water is stronger than that of crude oil. After entering the polymer, the ability of the solution to infiltrate into the formation is increased, the viscosity is increased, the flow of the solution is slowed down. Secondly, the flow resistance increases and the sweep efficiency increases by.4). Based on this, a new type of displacement technology with displacement and dual effect of profile control has been developed. It can greatly improve the mobility ratio, alleviate the contradiction among layers, and improve the recovery factor. It has a good application prospect. Under certain pressure, the profile control agent produces polymer gel in the formation channel, plugging the high osmotic water absorbing layer, and injecting water to turn. This technology overcomes the shortcoming of "gas channeling" in air drive, combines water drive with air drive, injects gas into the reservoir after water drive, reduces the permeability of water phase, reduces the fluidity of water and reduces the difference of water-oil fluidity ratio. This technology is very suitable for low permeability, serious heterogeneity and large pore channel reservoirs. It can solve many technical problems, such as low permeability in central and western regions of China, water shortage in local areas, water injection difficulty in injection wells, serious production hole formation deficiency, environmental pollution of produced water from oil wells, etc. Central Plains, Turpan-Hami and North China oilfields have all carried out on-site water-gas cross-injection and immiscible flooding experiments, and achieved good results. 6) CO2 flooding technology can meet the needs of extra-high water-cut oilfields to improve oil recovery, solve the problem of C02 storage, and protect the atmospheric environment. After C02 dissolves in water in formation, the viscosity of water increases by 20%-30%, and the migration performance increases by 2-3 times. After C02 dissolves in oil, the volume of crude oil expands, the viscosity decreases by 30%-80%, the interfacial tension between oil and water decreases, which is conducive to increasing oil recovery rate, oil washing efficiency and collecting residual oil. C02 can be obtained from industrial facilities, such as power plants, fertilizer plants, cement plants, chemical plants, refineries, natural gas processing plants and other emissions recovery, on the one hand, to reduce greenhouse gases, on the other hand, to increase production of oil and gas. 2, SH7 oilfield, according to its geological model, fluid model, water flooding, polymer flooding and crosslinked polymer flooding, the best combination scheme is obtained; 3) LN pure 56 oilfield, according to its development status, the water well profile control, oil well extraction and pressure reduction, nitrogen foam are proposed. 4) He11 Sha 2 oilfield, according to the development status, studied the feasibility of polymer profile control, water-gas alternate injection profile control, and polymer and water-gas alternate injection comprehensive profile control research, obtained the optimal program.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357

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