Technology and Practice of Stabiliing Oil Production and Controlling Water Cut in Kalamkas Oilfield in Central Asia

In this paper, by in-depth geological research of Kalamkas Oilfield in Central Asia, the geological body has been re-ascertained; combined with fine study of reservoir engineering, based on the understanding of the distribution of remaining oil horizontal wells have been given full play to stabilizing oil production and controlling water cut, reducing the producing pressure drop, improving well productivity and other advantages, and the development and deployment has been optimized; horizontal wells have been applied to solve problems such as old well casing damages, shutting down wells, low-productivity and low- efficiency wells, and high water cut wells to improve the utilization rate of old wells; through separate layer system improved injection production pattern, adjustment wells have been optimized and deployed, and part measures wells have been preferably selected to tap the residual oil improve the degree of reserves control realize the stabilization of oil production and control of water cut in an old oilfield, and further improve the development effects.

The Influence Law of Oil Relative Permeability on Water Cut

Water cut is a key evaluation parameter for reservoir development evaluation. Relative permeability curve reflects reservoir characteristics and fluid characteristics. It is important to figure out the influence law of oil relative permeability on water cut. Based on the 269 relative permeability curves of Bohai oilfields, the distribution of oil index of Bohai oilfields were studied. On the basis, combined with Corey expression of relative permeability and fractional flow equation, the theoretical relationship between oil index and water cut increasing rate was established. Three end points of water cut increasing rate curve were proposed and the influence law between three end points and oil index was studied. The results show that the oil index has a linear relationship with three end points. When the value of water oil mobile ratio is large than 1, with the increase of oil index, maximum value of water cut increasing rate gradually increase. When the value of water oil mobile ratio is less than 10, oil index has great effect on recovery percent when water cut increasing rate reaches to the maximum value as well as water cut when water cut increasing rate reaches to the maximum value. The application of SS field shows that the theoretical value is consistent with the field data.

Application Research of Oil Development Costs in Reservoir Management

Based on oil development costs, the application research in the technical and economic limits calculation of oil development and the production optimal allocation to all the oilfields, was finished. At the same time, according to the regression of real development costs, a new method for oil well economic water cut and oil well economic rate are set up, the production optimal allocation is developed with satisfactory results.

Analysis of Factors Influencing Shut in Pressure Cone in Offshore Strong Bottom Water Reservoir

X oilfield is an offshore strong bottom water reservoir with water cut up to 96% at present, and liquid extraction has become one of the main ways to increase oil production. However, the current liquid production of the oilfield reaches 60,000 m3/d due to the limitation of offshore platform, well trough and equipment, the oilfield is unable to continue liquid extraction. In order to maximize the oil production of the oilfield, it is necessary to study the strategy of shut in and cone pressure. Through numerical simulation, this paper analyzes the influence of different factors, such as crude oil density, viscosity, reservoir thickness, interlayer, permeability and so on, on the drop height of water cone and the effect of precipitation and oil increase after well shut in. At the same time, the weight of each factor is analyzed by combining the actual dynamic data with the fuzzy mathematics method, and the strategy of well shut in and cone pressure is formulated for the offshore strong bottom water reservoir. It provides the basis and guidance for the reasonable use of shut in pressure cone when the reservoir with strong bottom water meets the bottleneck of liquid volume.

窄条带状背斜油藏边部注水开发产能影响因素

JY油田Y油藏为典型窄条带状背斜油藏,其储集层注入水极易沿河道中心方向突进,导致油井快速水淹,产量递减快;由于对水体大小、构造幅度、储集层物性等产能影响因素认识不清,此类油藏开发难度较大。针对上述问题,建立了窄条带状背斜油藏精细数值模型,通过对比论证提出了“边部注水+逐步转注”开发,并在此基础上开展了水体大小、构造幅度、储集层物性等参数对产能的影响研究。结果表明:“边部注水+逐步转注”开发不仅可以增大边水能量,使得井网双向受效,还可以有效延缓构造高部位油井的见水时间,大幅度降低油井含水率。另一方面,在考虑油藏构造特征的前提下,量化了不同影响因素下的产能特征,明确了水体大小、构造幅度、垂向渗透率与水平渗透率之比等参数的合理界限,论证了不同储集层物性下油藏面积的适应性。可为同类型油藏改善注水开发效果提供借鉴。

D油田二类油层聚驱上返时机计算方法

为合理确定不同经济条件下的经济极限含水率,充分考虑油田效益最大化,评估油田生产是否具有经济效益,针对二类油层聚驱潜力层系接替投产时机问题,基于盈亏平衡原理与产量递减规律提出一种明确上返开发时机的新方法.打破选取98%(水的体积分数)作极限含水率行业标准的限制,基于油价、油田实际产出、成本和税金等经济参数,运用投入产出平衡理论,推导出聚合物驱油田单井经济极限含水率计算模型.利用产量递减规律预测处于后续水驱阶段的油层未来含水变化趋势,结合经济极限含水率,明确达到盈亏平衡点的时机,即层系接替投产时机.以D油田二类油层为例,计算不同油价和产液规模下的经济极限含水率,评价油井生产是否具有经济效益,并预测油田含水率变化,明确了开发投产时机.结果表明,经济极限含水率与油价和日产液量均呈正相关,对于具有较高采油速度的化学驱油层而言,高油价下的极限含水率可达99.02%,远超行业标准.根据建立的经济极限含水率模型预测的开发投产时机,延长了油井高含水期效益生产的寿命,大幅度提高了经济效益,对油田化学驱开发具有重要的指导意义.

基于低渗油藏裂缝型水淹泡沫复合调驱技术研究

针对裂缝型油藏水窜水淹以及传统的泡沫体系调控效果受限的问题,提出凝胶-泡沫复合调驱技术,并对其注入工艺进行优化研究。通过室内驱替实验对封堵增油效果进行评价,在此基础上,通过实验设计分别对体系的注入量、注入浓度、注入速度和注入方式进行优化,并进行矿场实践应用。实验结果表明,与单纯水驱相比,凝胶-泡沫体系最终采收率提高幅度达到19.7%。参数优化结果表明,当气液比为3∶1,起泡效果最好;注入量为0.3 PV、注入浓度为900 mg·L^(-1)·PV-1时,驱替效果最优;同时采取小排量、多段塞交替注入方式,驱油效率增幅比笼统注入方式下高6.79%。井场实践结果表明,措施后单井平均日增油1.59 t,含水率降低24.74%,增油率达到56.58%,降水增油效果显著。凝胶-泡沫协同调驱技术能够显著实现高含水井以及低效井降水增油的目的,针对裂缝型油藏注水开发中后期出现水淹水窜问题具有较好的治理效果。

水驱曲线标定技术可采储量的极限含水率

在动态法标定可采储量中,水驱曲线法是一种重要的方法。该方法是注水油藏不采取重大调整措施、不改变开发方式、水驱状况基本保持稳定时的向前预测,其将极限含水率标准定为0.98,缺乏科学依据。不同油藏的水驱规律存在很大差异,应在4种水驱特征曲线中选择最接近油藏实际的水驱规律,而不是以技术可采储量最低去选择,造成标定的技术可采储量可靠性不强。为此,将4种水驱特征曲线和产量递减法进行反演优选和联合消元,形成新的水(液)油比与递减产量关系式,不仅可以确定极限含水率,也实现了动态法标定技术可采储量结果的唯一性。

Stabilized oil production conditions in the development equilibrium of a water-flooding reservoir

Water injection can compensate for pressure depletion of production.This paper firstly investigated into the equilibrium issue among water influx,water injection and production.Equilibrium principle was elaborated through deduction of equilibrium equation and presentation of equilibrium curves with an“equilibrium point”.Influences of artificial controllable factors(e.g.well ratio of injection to production and total well number)on equilibrium were particularly analyzed using field data.It was found that the influences were mainly reflected as the location move of equilibrium point with factor change.Then reservoir pressure maintenance level was especially introduced to reveal the variation law of liquid rate and oil rate with the rising of water cut.It was also found that,even if reservoir pressure kept constant,oil rate still inevitably declined.However,in the field,a stabilized oil rate was always pursued for development efficiency.Therefore,the equilibrium issue of stabilized oil production was studied deeply through probing into some effective measures to realize oil rate stability after the increase of water cut for the example reservoir.Successful example application indicated that the integrated approach was very practical and feasible,and hence could be used to the other similar reservoir.

中心管采油设计方法及应用

在前人提出的中心管完井控锥基础上,针对水平井高含水情况,扩展了中心管完井的思路,提出中心管采油的概念。根据线汇叠加、镜像反映以及质量守恒和动量原理推导得到中心管耦合模型,利用模型计算了实例的流入剖面,对比中心管施工前后流入剖面,通过方案优选给出中心管施工推荐方案。现场施工一个多月后,采油量上升,含水率下降,达到了明显的增油降水效果,同时证明了采用中心管来调节油井高含水期生产指标是可行的。

特高含水采油期安全混输温度界限试验研究

随着油田开发的深入,大庆油田原油综合含水率不断升高,大部分油井产出液含水率在90%左右。随着含水率的升高,集输原油的能耗也呈急剧上升趋势。为了实现安全不加热集输及降低能耗和生产成本,在大庆油田建立了一套试验装置,以大庆油田采油六厂喇嘛甸油田特高含水油井产出的油气水混合物为试验介质,测试了不同温度、不同含水率、不同产液量及不同含气情况下的压降及油气水混合物的流动状态。试验研究结果表明,在含水率超过85%、产液量为11～105t/d、气油比为40～60m3/t及油气水混合物的流速为0.2～2m/s、气相折算速度为0.15～1.8m/s的条件下,油、气、水三相在水平管道内的流动属于冲击流,油、水两相属于分层流或水为连续相的乳状/悬浮液。在不加任何药剂的情况下,特高含水采油期,油气水安全混输温度界限为23℃,低于原油凝固点。

聚合物驱后凝胶复合体系调驱技术及应用

为提高凝胶体系对聚合物驱后高渗透地层的深部调驱效果,开发了由聚丙烯酰胺乳液、无机颗粒和Cr3+交联剂组成的凝胶复合体系。通过室内成胶实验,优选出了适合现场施工的6号和7号配方。室内封堵实验表明,在高渗透岩心中,注入7号配方的凝胶复合体系后,再驱8倍孔隙体积水,封堵率高达98.6%,说明该体系可以到达岩心深部发挥调驱作用,且7号配方的封堵效果优于6号配方。利用7号配方的凝胶复合体系对6个井组进行调剖后,注水井油压上升了1.8MPa,对应油井见效高峰时含水率下降了6.9%,累积增产原油1.1305×104t。

鄂尔多斯盆地致密油层混合水压裂试验

鄂尔多斯盆地长C储层岩性致密、物性差,采用常规工艺增产幅度有限,提高单井产量面临巨大的挑战。针对盆地长C致密储层的地质特征,借鉴国外致密油开发的成功经验,以体积压裂为理念,开展了致密油直井混合水压裂技术试验,取得了阶段性成果。通过对鄂尔多斯盆地致密储层混合水压裂先导试验的分析与总结,进一步探索长庆油田致密储层提高单井产量试验的新思路、新方法,为有效动用盆地致密油提供技术保障。

利用生产测井资料确定水驱油藏产层剩余油饱和度方法

利用常规电阻率测井资料和放射性测井资料确定油田注水开发期剩余油饱和度都有一定的局限性。本文提出并较系统地阐述了利用生产测井资料确定产层剩余油饱和度的理论和方法，同时提出一种利用岩心分析的油水相对渗透率和生产动态资料确定剩余油饱和度的产水率解释模型的实用方法。油田实例分析表明，与其它确定剩余油饱和度测井方法相比较，该方法具有不受地层水矿化度影响、结果代表范围大、实用性强等特点，更适合于确定水驱油藏产层剩余油分布及对其进行动态监测。

大庆喇萨杏油田产量递减率变化规律

给出了几种主要的产量递减率计算方法并研究了影响因素,分析了油田稳产期末产量递减率与稳产期的采油速度、稳产期长短和稳产期末可采储量采出程度的关系;研究了水驱油田自然递减率与含水率阶段、含水上升率和采液速度水平的关系;提出了结构递减率的概念,研究了不同结构对油田总递减率的影响,最后针对大庆油田水驱和聚合物驱共存的特点,定量分析了不同因素对递减率的影响幅度。对油田开发规划编制人员具有重要的参考作用。

油藏合理地层压力保持水平与含水率关系

地层压力是判断地层能量充足与否的一个重要标志。根据采油工艺基本原理和相渗关系推导出无因次采液指数和采液指数与含水率的关系式,在此基础上通过对油藏相对渗透率曲线的归一化处理,利用注采比原理,建立了不同采油速度下的合理地层压力与含水率以及注采比之间的关系,并给出油田应用实例。研究结果表明,无因次采液指数或采液指数取最小值时,合理地层压力保持水平会急剧降低。该方法对于分析中、低含水开发阶段注水工艺和采油速度具有一定指导意义。

水驱油田含水上升规律探讨及其应用

含水上升率与含水上升速度是反映油田地质因素和开发因素的综合指标,是评价油田开发效果和预测开发指标的核心指标。基于甲型和丙型水驱曲线建立了含水上升率与含水率的理论关系式,指出水驱油田含水上升率至少有2种变化形态,可以利用其变化规律来判断水驱曲线的应用条件;分析指出含水上升率与含水上升速度之间为线性关系,斜率为地质储量采油速度,基于此建立了利用动态资料评价采油速度的方法,并同时给出了含水上升速度与含水率及采油速度之间的理论关系式,可以用来评价含水与采油速度的高低。实例应用结果表明所得到的理论关系式具有良好的适用性,所得的研究成果对矿场应用和理论研究具有较高的借鉴意义和指导价值。

低渗透油藏中高含水油井增产技术研究与应用

长庆油田储层属于典型的低渗透,需要注水进行开发,随着开发时间的延长,部分区块进入开发中后期,油井含水不断上升,给油井增产改造带来了很大困难。通过对长庆低渗透储层特征、开发现状、见水原因分析的基础上,通过室内研究,形成了注水井深部调剖、油井堵水、堵水压裂、裂缝深部暂堵酸化等中高含水油井增产技术。目前在现场应用61口井,取得了较好的措施效果,为长庆油田低渗透储层中高含水油井提高单井量进行了有力探索。

喇萨杏油田剩余储量潜力分析及挖潜方向

建立了利用水驱特征曲线和相对渗透率曲线结合计算各类井地质储量的新方法并对喇萨杏油田各类井地质储量进行了测算。采用动静结合的方式, 分析了喇萨杏油田剩余储量分布特点, 明确了油田进一步调整挖潜的方向。研究了喇萨杏油田水驱分类井控制剩余可采储量比例、含水、采油速度等开发状况, 分析了目前开发中存在的主要问题和矛盾, 针对各类井网目前含水接近的情况, 论证了满足一定产油量约束下的各类井产液比例与产油比例尽量接近于它们的地质储量比例时控水效果最好。应用此结论, 研究了喇萨杏油田水驱分类井优化结构调整开发方式。

海上中高含水油田提液潜力动态计算方法

提液是海上中高含水油田减缓产量递减的一项有效措施。基于生产动态数据的油井提液动态分析方法克服了传统方法对区域静态资料的依赖性和局限性，但常规动态法只能计算无因次采液指数，难以量化提液潜力。基于渗流理论，首先建立油井无因次采液指数与含水率的定量表征关系，在此基础上研究油井无因次历史最大合理生产压差确定方法，并进一步提出油井最大产液量实时计算方法，从而达到动态法直接量化油井提液潜力的目的。应用实例表明，W油田实施提液后各井产液量基本达到了计算值，证实了该方法的合理性。该方法仅需要油井产液量和产油量2个基本生产动态数据就可以直接量化油井提液潜力，克服了海上油田区域静态资料不足的问题，具有数据基础简单、结果合理、操作简便和可实施性强等优点，可广泛应用于海上中高含水油田提液潜力评价。