Study of the Law about Water-Cut Variation for the Fractured Metamorphic Reservoir of Buried Hill with Bottom Water

Aiming at the complex flowing environment including the buried hill of Metamorphite, the active bottom water and the fracture at Budate Reservoir within Beir Depression of the Hailar Basin, combining the laboratory studies and based on analysis of its drive mechanism, field wells’ parameters were used to analyze the effects of different conditions of the fractured metamorphic reservoir with bottom water on its law of wa-ter-cut variation and the waterflooding efficiency. The results show that for the Budate buried hill reservoir with bottom water, the gravity should be taken into consideration to determine reasonable perforation ratio and production pressure difference. And because of the acid sensitivity of the buried hill reservoir, application of proper clay stabilizer will enhance the field oil recovery to a satisfactory extent.

Water-cut rising mechanism and optimized water injection technology for deepwater turbidite sandstone oilfield: A case study of AKPO Oilfield in Niger Delta Basin, West Africa

Through the analysis of the reservoir connection relationship and the water-cut rising rules after water breakthrough in the highly volatile oil AKPO oilfield, a new model of water-cut rising was established, and the timing and strategy of water injection were put forward. The water-cut rising shapes of producers after water breakthrough can be divided into three types, and their water-cut rising mechanism is mainly controlled by reservoir connectivity. For the producers which directly connect with injectors in the single-phase sand body of the single-phase channel or lobe with good reservoir connectivity, the water-cut rising curve is "sub-convex". For the producers which connect with injectors through sand bodies developed in multi-phases with good inner sand connectivity but poorer physical property and connectivity at the overlapping parts of sands, the response to water injection is slow and the water-cut rising curve is "sub-concave". For the producers which connect with injectors through multi-phase sand bodies with reservoir physical properties, connectivity in between the former two and characteristics of both direct connection and overlapping connection, the response to water injection is slightly slower and the water-cut rising curve is "sub-S". Based on ratio relationship of oil and water relative permeability, a new model of water cut rising was established. Through the fitting analysis of actual production data, the optimal timing and corresponding technology for water injection after water breakthrough were put forward. Composite channel and lobe reservoirs can adopt water injection strategies concentrating on improving the vertical sweep efficiency and areal sweep efficiency respectively. This technology has worked well in the AKPO oilfield and can guide the development of similar oilfields.

Wall Sticking of High Water-Cut, Highly Viscous and High Gel-Point Crude Oil Transported at Low Temperatures

Some crude oils with high water cut have the capability to flow below the oil gel point, while the oil particles adhere to the pipe wall in the form of paste, also called "wall sticking". Wall sticking is a serious problem during the pipeline transportation, leading to partial or total blockage of the pipeline and energy wastage. In this paper, a series of laboratory flow loop experiments were conducted to observe the wall sticking characteristics of crude oil with high water cut, high viscosity and high gel point at low transportation temperatures. The effects of shear stress and water cut on the wall sticking rate and occurrence temperature were investigated. Experimental results indicated that the wall sticking rate and occurrence temperature were lower under stronger shear stress and higher water cut conditions. A criterion of wall sticking occurrence temperature(WSOT) and a regression model of wall sticking rate were then established. Finally, the software was developed to calculate the pressure drop along the pipelines of crude oils with high water-cut. It was able to predict the wall sticking thickness of gelled oil and then calculate the pressure drop along the pipelines. A typical case study indicated that the prediction results obtained from the software were in agreement with actual measured values.

Layer regrouping for water-flooded commingled reservoirs at a high water-cut stage

Layer regrouping is to divide all the layers into several sets of production series according to the physical properties and recovery percent of layers at high water-cut stage, which is an important technique to improve oil recovery for high water-cut multilayered reservoirs. Dif- ferent regroup scenarios may lead to different production performances. Based on unstable oil-water flow theory, a multilayer commingled reservoir simulator is established by modifying the production split method. Taking into account the differences of layer properties, including per- meability, oil viscosity, and remaining oil saturation, the pseudo flow resistance contrast is proposed to serve as a characteristic index of layer regrouping for high water-cut multilayered reservoirs. The production indices of multi- layered reservoirs with different pseudo flow resistances are predicted with the established model in which the data are taken from the Shengtuo Oilfield. Simulation results show that the pseudo flow resistance contrast should be less than 4 when the layer regrouping is implemented. The K-means clustering method, which is based on the objec- tive function, is used to automatically carry out the layer regrouping process according to pseudo flow resistances. The research result is applied to the IV-VI sand groups of the second member of the Shahejie Formation in the Shengtuo Oilfield, a favorable development performance is obtained, and the oil recovery is enhanced by 6.08 %.

弱酸性电解水用于提升鲜切马铃薯安全品质的研究

目的探究弱酸性电解水和自来水处理的鲜切马铃薯在室温贮藏条件下不同时间段内品质的变化。方法模拟现代厨房贮存模式,经弱酸性电解水和自来水处理的鲜切马铃薯在室温(25±0.5)℃贮藏环境下,贮藏0、7、14、21、28、35h时,检测其感官、色度、质构、淀粉、蛋白质、钾、维生素C、菌落总数、大肠杆菌、沙门氏菌、金黄色葡萄球菌、霉菌、酵母菌。结果经弱酸性电解水处理的鲜切马铃薯在室温贮藏21 h内,经自来水处理的鲜切马铃薯在室温贮藏14 h内,感官正常,其营养成分淀粉、蛋白质、维生素C、钾元素下降较少,金黄色葡萄球菌、沙门氏菌、菌落总数、大肠杆菌、霉菌、酵母菌的含量均在国家标准和团体标准许可的安全范围内,可安全食用。结论弱酸性电解水可显著提升鲜切马铃薯的贮藏品质,抑制其金黄色葡萄球菌、沙门氏菌、菌落总数、大肠杆菌、霉菌、酵母菌繁殖,延长室温贮藏期。

高含水油井关停后剩余油再富集速度研究

高含水断块油藏开发末期构造高部位油井在关井一段时间后,会产生剩余油再富集现象。目前关于剩余油再富集速度的研究中,对剩余油运移过程的影响因素考虑不够全面,影响计算精度。针对该问题,在对运移中剩余油再富集受力分析的基础上建立小油滴状和柱状剩余油再富集速度模型,通过正交试验确立2种剩余油再富集速度的主要敏感因素,并建立了2种剩余油再富集速度及再富集时间图版。研究结果表明:存在驱替压差时,储层渗透率为影响2种剩余油再富集速度的主控因素;当储层渗透率一定,驱替压差的增大和原油黏度的减小有利于2种剩余油再富集速度的增大;同一注采井距位置处的小油滴距离孔隙中滞留柱状剩余油越近,聚集过程中剩余油再富集时间越长,但数值上增加不多。该研究对高含水油藏剩余油再富集潜力区评价具有借鉴意义。

稠油自乳化水驱开发规律

受原油性质的影响,稠油自乳化水驱开发与常规水驱开发不同,传统的稀油水驱理论不适用于稠油水驱开发。以中国某稠油自乳化水驱油藏流体参数为基础,通过室内实验和数值模拟,研究自乳化水驱开发规律,揭示自乳化水驱机理和主要影响因素。采用新的数值模拟方法揭示自乳化水驱的稳定驱替阶段为类“活塞式”驱油模式,开发全过程可分为4个阶段,即纯油阶段、过渡阶段、平台阶段和水油比快速上升阶段。渗透率级差和原油黏度是影响自乳化水驱含水率的主要因素,其次是渗透率和注水速度。

基于投影寻踪模型的特高含水油藏剩余油可采潜力评价方法

影响特高含水油藏剩余油可采潜力的因素极其复杂,且各因素的影响程度差异明显,常规方法多以剩余油饱和度或剩余油储量丰度等单一指标评价剩余油潜力,难以有效指导特高含水油藏剩余油挖潜。在充分考虑特高含水油藏剩余油可采潜力影响因素的基础上,综合表征储层非均质性、剩余油可采储量规模、水淹状况以及油水分流能力的差异,构建了特高含水油藏剩余油可采潜力量化评价指标体系,并考虑不同指标对剩余油可采潜力控制程度的差异,将加速遗传算法与投影寻踪模型相结合来确定各评价指标的客观权重,从而构建了剩余油可采潜力指数,形成特高含水油藏剩余油可采潜力量化评价新方法。以渤海Q油田南区主力产层NmIL砂体为例,开展特高含水油藏剩余油可采潜力量化评价,结果表明,新方法可综合表征不同区域位置的储层物性、可采储量丰度和油水分流能力对剩余油可采潜力的影响,实现了主力产层NmIL砂体剩余油可采潜力分布的差异化定量评价,优势可采潜力区域刻画明显,将其作为NmIL砂体下一步井网加密调整潜力区域,以精准指导加密水平井的部署,为特高含水油藏剩余油挖潜提供了一种全新的分析方法与思路。

断块油藏高含水井关井后剩余油再动用运移规律微观模拟

基于微观可视化光刻玻璃模型,从微观角度定性、定量研究了断块油藏高含水井关井后剩余油再动用运移规律,并开展了影响因素分析。结果表明:水驱后关井期间剩余油再动用类型主要为滴状、柱状和簇状。关井期间剩余油会沿模型倾斜方向向高部位运移聚集,有利于后续水驱阶段进一步提高驱油效率。地层倾角的增大、原油黏度的减小有利于剩余油再动用;关井时间的增加有利于剩余油向高部位采出端接近聚集;后续水驱阶段注入速度的增大会增加波及面积。

高含水老油田化学驱综合治理新方法及工程实践路径

针对胜利高含水老油田化学驱在科学、技术、管理、工程四个角度面临的开发矛盾,以渤76块为典型单元,在工程实践中进行具体对策分析,构建了“适、专、快、集”的老油田化学驱综合治理新方法。“适”指在老油田科学开发方式转化上,构建不同油藏类型老油田化学驱最佳介入时机模型,提出了在含水率相对较低的阶段,是适合化学驱的有利时机,高效开发方式需“适”介入。“专”指在老油田开发技术应用上,改变传统聚合物先溶解后注入的开发思路,研制可控相转化聚合物,使聚合物先注入后溶解,解决炮眼剪切降解的难题,提高油水流度控制能力,老油田开发矛盾需“专”治理。“快”指在老油田综合管理模式上,改变传统方式,即矿场提问题、研究院设计方案、化工厂生产驱油剂的“串联”管理模式,提出充分发挥矿场、研究院、生产厂三方优势的“并联”管理模式,形成针对单一油藏的产品工业化工艺包以及产业化落地方案,老油田开发技术实现“快”转化。“集”指在老油田工程应用实践上,打破老油田化学驱地面大规模建站的工程工艺模式,采用集约化撬装配注设备,实现老油田化学驱的集约快速配注,老油田工程工艺实现“集”应用。运用上述方法,在胜利油田渤76块综合含水率上升初期,实施由水驱转为可控相转化聚合物驱,实施后一年即见到明显的降水增油效果,单井日产油水平增加8.6t/d,综合含水率降低3.1%,验证了综合治理模式的可行性,为高含水老油田化学驱高效开发提供了有效路径。

微波含水率检测技术在复杂油水混合形态下的应用研究

在油水混合物中会出现不同的乳化形态,不同的乳化形态对应的电导率和介电常数也具有显著差异,从而导致通过检测电导率和介电常数值间接测量含水率的测量结果不准确。针对复杂油水混合状态下含水率难以测准的问题,提出一种基于微波技术的复杂油水两相流含水率检测技术,建立了基于微波技术的“油包水”和“水包油”状态分析方法。首先通过检测微波信号穿过不同介质后信号幅值的衰减和相位的偏移,推测油水混合物的含水率值。再利用不同输入功率的微波信号在不同介电常数下功率衰减比不同的原理,来区分油水混合物的乳化状态,优化含水率的测量。室内验证和矿场试验结果表明,该系统可有效区分乳化液的混合状态,通过含水率标定值对实测数据进行修正,最终测量的含水率误差可控制在1个百分点以内,实现了复杂油水混合形态下含水率的高精度测量。

高含水致密凝析气藏稳产技术应用——以四川盆地安岳气田须家河组气藏为例

四川盆地安岳气田上三叠统须家河组二段气藏为低孔、低渗、有水、中含凝析油、弹性气驱、高压岩性圈闭的砂岩气藏,气藏底水能量充足。针对气井生产过程中受地层水水侵和反凝析污染影响造成稳产难度较大的情况,结合储层及气井产液特征,开展有水凝析气井稳产技术应用实践,分析并总结应用实践经验和成果,选取了应用效果较好的注气吞吐、电潜泵排水、车载压缩机气举、柱塞气举排液和自动化开关井5种稳产技术。结果表明:①针对储层反凝析液伤害,形成单井注气吞吐技术应用选井原则;②针对气藏水体赋存特征和水侵模式特征,调整气藏排水采气对策思路,采用电潜泵排水技术和车载压缩机气举技术;③针对地层压力低、举升能量不足,优化油、气、水三相流动条件下的柱塞气举排液技术;④针对低压间歇生产井采用自动化开关井技术,增加生产效率,降低人工成本。对5种主要稳产技术的应用情况进行了分析评价,认为一系列稳产技术的应用有助于安岳气田须二段气藏稳定生产,为类似高含水致密凝析气藏的稳产提供了借鉴和参考。

缓交联高强度封堵剂研究进展

综述了目前油田主要应用的封堵剂的发展情况,介绍了含水率较高的油田实施窜流封堵技术,分析了不同类型的深部封堵剂优劣特性及适用情况,总结和展望了未来缓慢交联的封堵剂技术的发展趋势。

Variability in Quantity and Salinity of Produced Water from an Oil Production in South Kuwait

Produced water (PW) is the largest waste stream in the oil and gas industry. Water remains trapped for millions of years in the reservoir with oil and gas. When a hydrocarbon reservoir is infiltrated by a production well, the produced fluids commonly contain water. The understanding of this water’s constituents and volumes is vital for the sustainable continuity of production operations, as PW has a number of negative impacts on the infrastructure integrity of the operation. On the other hand, PW can be an alternative source of irrigation water as well as of industrial salt. Interestingly, both the quantity as well as the quality of PW do not remain constant but can vary, both progressively and erratically, even over short periods of time. This paper discusses such a situation of variable PW in an oil and gas operation in the State of Kuwait.

基于混凝土切割面统计方法的纤维取向分布研究

纤维分布和取向是影响纤维增强混凝土力学性能的重要因素。本文采用混凝土切割面统计方法研究不同水胶比和振捣时间对钢纤维混凝土中纤维分布及取向的影响。结果表明:随着水胶比和振捣时间的增加,边壁效应对纤维分布影响减弱;高水胶比条件下纤维在垂直于振捣方向上出现了偏析现象(垂直方向上的不均匀分布),随振捣时间增加,偏析更显著;对于高性能混凝土,增加振捣时间有利于纤维的均匀分布,而普通混凝土应缩短振捣时间。此外,统计结果表明,钢纤维取向角分布呈现高斯分布规律,峰值处于40°~50°。当水胶比为0.45,振捣时间为20 s,纤维取向角在45°附近,纤维数量占比最大,纤维取向系数达到0.73。

新型产甲烷菌系提高极限含水油藏采收率技术

我国东部老油田已整体进入特高含水开发阶段,呈含水上升快、采油速度低、水驱效益低等开发特征,现有提高采收率技术已无法实现原油的经济采出,亟需建立接替技术。为此,以胜利油田某聚驱后油藏为试验区,开展了油藏菌群结构分析、新型产甲烷菌系的激活产气、油藏适应性及驱油性能研究,探索新型产甲烷菌系在这类油藏的应用潜力。研究结果显示,试验区油藏具有丰富的石油烃降解菌,有利于生物气化技术的实施。模拟试验区油藏条件下,新型产甲烷菌系与油藏内源微生物有较好的相容性,90 d每克原油的产气量达到3.12 mmol,是单独激活油藏微生物产气量的4.5倍,且产生的气体中甲烷气占比达到78%。菌群结构分析显示,新型产甲烷菌系占比达到35.9%,是产气速率大幅提升的关键。适应性研究结果显示,在油藏温度低于65℃、原油黏度小于1 356 mPa·s条件下,新型产甲烷菌系均展示了良好的产气性能。利用实验室设计的物理模型,评价了该菌系产气提高驱油性能,结果显示,注入该菌系后产气作用有效动用了模型顶部的剩余油,极限含水条件下驱油效率提高5.4个百分点;在此基础上提出了生物气化技术提高极限含水油藏采收率的机理。

极端耗水层带形成机制及流场调控增效模式——以陆相砂岩特高含水后期整装油田为例

以胜利油区陆相砂岩油藏整装油田为代表,主力单元进入特高含水后期(含水率大于95%),局部区域出现极端耗水现象,水油比急剧上升,注入水利用率大幅下降,吨油操作成本成倍增加,经济效益变差,但油藏中还有60%左右剩余地质储量。注入水沿着极端耗水层带窜流是制约陆相砂岩整装油田特高含水后期效益开发的关键问题。以提高特高含水老油田开发效益为目标,明晰了极端耗水层带形成机制及调控机理,建立了基于老井的变流线调控极端耗水层带扩波及方法,形成特高含水后期油藏精准描述及调控极端耗水层带扩波及的效益开发技术体系。通过应用流场调控技术,使传统认为含水率98%近废弃油藏开展示范应用,基于极端耗水层带流场调控经济寿命期延长10a以上,产油量大幅增加,含水率下降,吨油操作成本下降,实现了特高含水后期老油田低成本开发。

江苏油田复杂小断块高含水油藏注采井网优化技术

江苏油田复杂小断块油藏经过长期的注水开发后,目前处于中高含水开发期。现阶段储层非均质性对注采井网的影响更加突出,局部存在低效无效注水循环问题,亟需优化调整注采井网。根据非均质油藏剩余油富集类型和影响因素,在原井网基础上,利用油藏数值模拟方法,开展相控条件下的注采井网优化技术政策研究。根据模拟结果,确立了抽稀井网和转注高含水油井两种注采井网优化技术的政策界限,指导陈2断块、韦2断块注采井网优化调整,取得了良好的应用效果,为改善高含水油藏水驱开发效果提供了技术支撑。

Kenics型静态混合器对含水原油均质化效果影响数值模拟

目的针对含水原油在输送过程中水分分布不均匀或大量聚集的现象,将Kenics静态混合器引入到含水原油输送过程中,并对其均质化效果进行分析。方法采用FLUENT软件对管道内流场进行模拟,并用变异系数和液滴平均粒径对均质化效果进行评价,分析了混合单元排列方式、扭角、长径比和数量对均质化效果的影响。结果使用排列方式为异向叉排、扭角为240°、长径比为0.5、数量为10个的Kenics静态混合器不仅能使油水两相分布均匀,还能获得更小的液滴平均粒径,从而实现更好的均质化效果。结论排列方式为异向叉排时均质化效果最好;随着扭角的增大,管线出口的变异系数和液滴平均粒径呈下降趋势;随着长径比的减小和数量的增多,出口的变异系数值趋于相同,但能获得更小的液滴平均粒径。通过均质化处理后,可以使取样样本更加准确地体现储罐原油的含水率,避免造成油品交接纠纷,保证油品外输任务的完成。

高强度堵剂优化及其在高含水油藏靶向调堵中的应用

针对河南油田高渗高凝特高含水砂岩油藏,对双激发无机堵剂的配方优化、耐温耐盐性能、封堵性能、耐冲刷性能、粒径匹配等多方面进行系统研究。结果表明,缓凝剂和离子平衡剂是控制体系凝固时间的主导因素,随着主剂与激发剂浓度以及温度的增加,双激发无机堵剂固结速度增大。配液水中矿化度较高时,硫酸根和氯盐会加快体系固结时间。双激发无机堵剂封堵能力强,耐冲刷能力和深部液流转向效果较好,可对高渗透层大孔道有效封堵,提高低渗岩芯分流率,其封堵率高于98.5%。现场应用效果证实,双激发无机堵剂能够实现深部靶向封堵,具有强度高、有效期长、成本低等优点,调堵后含水率大幅下降。