Investigating the efficiency of gas re‐injection process of an oil field using combined integrated field simulation and intelligent proxy model application

Integrated asset modelling is a novel method to overcome the limitations associated with using individual models. This method integrates all the individual models of a field into a single model that relates all the sub‐models using proper boundary conditions. Reservoir, wells, surface, and economic models of an oil reservoir, under gas re‐injection, are integrated. The main goal of this study is to propose a novel approach in integrated asset modelling. An integrated model of a field is used to study how gas must be distributed among injection wells. Another aim of this study is to understand the effects of 4 input parameters on the Net Present Value (NPV) of the field. The input variables are: oil production rate, gas injection rate, and the distribution of gas between injection wells. A comprehensive model of a field was built. Using the experimental design results, a neuro‐fuzzy logic network was developed. The proxy model predicted the simulation outputs with a reasonable accuracy. The effects of input variables were studied. Oil production has an optimum value of 6050 STBD per well. The optimum fractions of injected gas for injection wells 1 and 2 are 0.4 and 0.6 of total injected gas, respectively. This means that 40 % of the total injection gas must be injected to well 1 to have the maximum NPV. The greater the gas injection rate, the higher NPV is.

     

GO7-23-5206井组凝胶调剖设计及效果分析

井间动态连通性是油藏动态分析的重要内容之一。孤东七区具有高孔高渗、强非均质、储层结构疏松、易出砂的特征。由于孤东油田水驱不均匀,使注入水在平面上形成水驱水流优势通道,从而有可能降低水的扫驱效率。针对这一严峻形势,先用流管图模拟出大孔道以及具有注采对应关系的注水井组。为后期调剖,选井选层提供重要的依据。并且通过连通性分析可以判别水流优势通道分布,最终达到提高采收率的目的。系统开展窜流通道定量化调剖技术提高采收率的研究。选定了一个具有代表性的典型注水井组,以凝胶为调剖剂,利用CMG软件,通过对凝胶的注入量和注入时间,从而确定注入速度,最后根据投入产出比,优选出最合适的方案,并在现场实施中获得良好的效果。     

周期注水改善水驱效果原理及适用条件分析

通过国内外长期的理论研究和矿场实践,从研究区常规注水效果减弱,开发效果变差的现状分析,若要提高剩余油的采收率,需要在地层中施加一个不稳定压力场使得地层中油水不断进行交换和重新分布,因此开展周期注水是非常必要的。油藏若要采用周期注水,需明确储层非均质特征、油层不连通程度、注水工艺与注水量要求等基本参数,从而确定周期注水的方式以及合理的注水时机,以便取得良好的开发效果。     

Optimization strategies and impact of low oil price on long term SAGD projects

Steam assisted gravity drainage (SAGD) has been known as a commercially proven high ultimate recovery process for bitumen and heavy crudes. It is an energy intensive process, which is economical when oil price is above certain value. When the oil price goes below the economic threshold of project, steam injection can be decreased or completely stopped for a certain period of time, and can resume thereafter when the condition alters. The objective of this study is to provide comprehensive information about the effect of steam injection interruptions on thermal project performance. An optimization strategy for the SAGD process, in cases where steam injection interruption occurs, is discussed using actual reservoir models of different geological formations. An economical model is used to evaluate operating strategy effect on the net present value (NPV) of the project. The parameters, like shut-in period, initial steam injection period, etc, are optimized for Athabasca type oil sand reservoirs. The results show several key mechanisms exist in the life cycle of the SAGD process that must be included to reflect the field scale behaviour; otherwise, the mechanistic simplicity of the models could lead to directional and semi-quantitative conclusions. Among the mechanisms, temperature effect on basic petrophysical properties of reservoir rocks was found to have an important role in the oil recovery, and considerably impacts the results of optimization. When the steam injection is interrupted, an optimum shut-in period can be determined to maximize the oil recovery. The optimum length of steam injection interruption depends on the initial steam injection period.     

改善复杂河流相稠油油田水驱开发效果对策

复杂河流相油田由于先天地质条件复杂,砂体连通性难以把握,同时海上开发这类油田仍以大井距多层合采为主,加剧了注采间矛盾。以渤海B油田为例,通过油藏工程方法评价油田注水开发存在的问题,然后选取典型井组通过油藏数值模拟方法,开展注水井排液时间及合理转注时机、合理注采比、合理油水井数比等方面优化工作,提出该类油田设计注水井排液1~2年后应适时转注,合理注采比应保持在0.9左右,油水井数比保持在1.4左右,同时应优化注采井网,考虑在物性较差的河道边部部署注水井,在物性较好的河道中部部署采油井,提高注入水利用效率改善水驱开发效果。     

低渗透油田水驱开发效果评价—以N区块为例

低渗透油田开发进入中后期,合理评价注水效果是制定合理精细注水政策的前提和基础。通过地层压力与饱和压力关系分析压力保持水平级别,利用相对渗透率曲线得出含水率与采出程度理论曲线,通过与实际曲线位置关系评价开发效果好坏。利用水驱指数与注采比关系,计算得出不同注采比条件下标准图版,将实际曲线与同类油藏存水率、水驱指数标准图版对比评价水驱开发效果。研究表明,N区块生产能力较好,采液量、注水量差异与地层压力变化保持一致,利用含水率与采出程度关系图版、存水率图版、水驱指数图版评价油藏开发效果较好。     

秦皇岛32-6南区少井高产虚拟开发研究

秦皇岛32—6南区原油粘度高密度大,具有常规稠油的特点,目前生产状况极不乐观。本文采用数值模拟方法,对边底水油藏进行了垂向渗透率及开采速度敏感性分析,从储量合理动用、先进井型确定、合理产能设计等几个方面进行了虚拟开发研究。结果表明,秦皇岛32—6油田南区采用水平井开发可有效提高采出程度,改善开发效果。开发过程中先动边水主力油藏、然后动用边水构造岩性油藏、最后动用底水油藏可取得最佳开发效果。通过虚拟开发,提出了少井高产的思路。     

渤海疏松稠油油藏调堵技术及新发展

我国油田开发的中后期,常用注水的方式来提高地层能量。由于油层的非均质性,会出现水"突进"以及"窜流"等问题。如果严重的话,还会极大影响油田的开发效果。渤海湾海上稠油砂岩油藏,长期实施注水开发,加剧了储层的非均质性,导致含水率上升过快,产量下降快等问题。为了改善注水效果和提高采收率,在油田开发的过程中应用堵水调剖技术。对渤海湾调堵技术的发展现状进行了相关的分析。     

大庆油田S区块水驱后聚合物驱注入方式优化研究

针对大庆油田水驱开发相继进入高含水阶段的现状,聚合物驱作为水驱后接替开发方式,大大减缓了大庆油田的产量递减.基于大庆油田水驱后聚合物驱的发展现状,模拟大庆油田S区块的油层条件,采用室内物理模拟实验方法,进行了水驱后聚合物驱注入方式的优化研究,主要研究了聚合物恒速恒浓、恒速梯次增浓、恒速梯次降浓和增速梯次降浓四种注入方式的驱油效果,通过对比采收率指标,最终确定了水驱后聚驱的最优注入方式为增速梯次降浓,为大庆油田S区块水驱后聚合物驱注入方式的优选提供了指导.     

Modeling and optimization for oil well production scheduling☆

In this paper, an oil wel production scheduling problem for the light load oil wel during petroleum field exploi-tation was studied. The oil well production scheduling was to determine the turn on/off status and oil flow rates of the wel s in a given oil reservoir, subject to a number of constraints such as minimum up/down time limits and well grouping. The problem was formulated as a mixed integer nonlinear programming model that minimized the total production operating cost and start-up cost. Due to the NP-hardness of the problem, an improved par-ticle swarm optimization (PSO) algorithm with a new velocity updating formula was developed to solve the problem approximately. Computational experiments on randomly generated instances were carried out to eval-uate the performance of the model and the algorithm's effectiveness. Compared with the commercial solver CPLEX, the improved PSO can obtain high-quality schedules within a much shorter running time for all the instances.     

应用模糊评判法评价塔河油藏水锥风险

塔河底水缝洞型油藏投入开发以来,每年因含水上升导致产量递减占65％左右,如何做好控水工作是开发中的重要任务。针对塔河油田的实际情况,利用各种静、动态资料和测试手段,在相关地质研究成果和开发特征分析的基础上,依据备类缝洞单元的储集体发育、含水变化规律、天然能量等方面的研究,深化塔河油田缝洞型储集体的认识,结合注水替油井现场生产动态数据及监测资料,在总结前人研究成果的基础上,应用模糊综合评判法评价缝洞型储集体水锥风险,及早提出预警方案。生产实践评价结果表明,建立的水锥风险预警方法具有一定适应性,在一定程度上对油田开发生产管理可以起到辅助决策的作用,为提高缝洞型碳酸盐岩油藏采收率提供技术支撑。     

断块油藏注采系统评价方法与应用

我国大部分注水开发油田已经进入特高含水期,为了实现稳油控水,寻找合理的注入压力水平,针对魏岗某断块油藏注采系统,从井网储量动用程度、井网密度、注采比评价、压力保持水平四个方面入手,借助油藏数值模拟技术和油藏工程方法,分析了整个断块注采系统的情况,确定了注采压力系统合理组合,对现场注采比调整具有一定的指导作用。     

齐家北油田数值模拟合理注采比研究

本文针对齐家北油田储层物性差异,将油田分为古708区块和古704区块,通过对两个区块不同注采比进行数值模拟,以及不同含水对应的采收率情况,确定合理的注采比。提高了油田注水开发方案的针对性和有效性,对提高扶余油层开发效果具有一定的指导作用。     

齐家北油田数值模拟合理注采比研究

本文针对齐家北油田储层物性差异,将油田分为古708区块和古704区块,通过对两个区块不同注采比进行数值模拟,以及不同含水对应的采收率情况,确定合理的注采比.提高了油田注水开发方案的针对性和有效性,对提高扶余油层开发效果具有一定的指导作用.     

低渗透油田注水井深部调剖技术完善与推广

陇东油区油层属低产、低渗、低压三低油田,区块较多。各区块平面上、纵向上渗透率分布差异大,导致注入水或边底水沿高渗带、大孔道、裂缝指进或锥进,使油井过早见水,并很快水淹,降低了油田采收率。为了遏制油井含水上升过快的势头,提高水驱动用程度和采收率,研究适应陇东油区的堵水调剖技术,满足封堵大孔道、驱替小孔道残余油、剥离岩石孔隙中的油膜的目的,从而提高中高含水期的水驱效率,达到提高采收率的目的。本次研究综合运用示踪剂分析、脉冲试井、PI决策、水驱前缘测试4种方法,开展对储层的见水类型、见水方向、窜流程度研究与分析;对于三叠系裂缝油藏堵剂进行了优选与评价并且提出了堵水调剖方案优化设计方法。     

吴起油田Gemini表面活性剂性能评价研究及应用

Gemini表面活性剂各个体系的表面张力为30mN·m-1左右。在长2油藏条件下,在一定的使用浓度范围内均可使油水界面张力达到0.1~1mN·m-1,在浓度为0.3%时可提高不同渗透率岩芯采收率10%~15%,使用0.5%驱油剂能提高采收率达19.84%。袁和庄2号站现场试验区生产数据对比来看,产液、产油、含水波动较大。试验区注入驱油剂后产量明显增加的有25~35口,日增加产量5.91~10.2t·d-1,其含水稳定,产液量和产油量增加。     

人工地震采油技术机理研究与分析

人工地震采油技术是利用一定的设备在油层附近产生频率很低的机械波,通过声波的特性在油层发生一系列的波动效应,达到多口井增产增注的一种物理采油方法。它是一种适应低渗透、高含水中后期油田开发的比较理想的物理法采油技术。作者对其作用机理进行了理论分析、归纳和总结,为该技术的进一步深入研究做铺垫。     

鄂尔多斯盆地王渠则地区延安组延9油藏注水开发论证及部署

鄂尔多斯盆地王渠则区侏罗系延安组延9油层组为研究对象,在油藏地质条件研究、精细储层描述及油藏开发中存在的问题研究基础上,通过注水开发适应性、注水方式和注水时机的分析,对延9油藏进行了注水开发部署,以期提高油藏最终采收率。研究认为：王渠则区延9油藏自然能量较低,天然能量采收率不到13％,而理论计算水驱采收率为30％左右,明显优于采用天然能量开采。同时该区储层连通性较好及中等酸敏、弱或无速敏、中等水敏,有利于注水进入地层。本次方案共新部署采油井32口,注水井5口,转注采油井23口。     

古城油田B124复杂断块油藏精细数值模拟

古城油田B124区属于复杂小断块稠油砂岩油气藏,构造复杂、非均质严重,本文在地质研究和分析油藏开发过程中存在的主要问题的基础上,对其进行了精细油藏数值模拟研究,以原始井网注采单元为对象,结合产液和吸水剖面资料,重点针对油水井之间的驱替、连通关系和剩余油分布规律进行了研究。剩余油分布主要受非均质严重、构造复杂、井网完善程度等因素的影响,剩余油主要集中于断层边部、油砂体边部、微构造高点、井网未控制区域、纵向上物性差层等。优化得到合理的注采比和压力水平,引入矢量化井网,设计出了后期调整开发方案,采出程度能提高4.46%。     

Laboratory Studies to Determine Suitable Chemicals to Improve Oil Recovery from Garzan Oil Field

Garzan oil field is located at the south east of Turkey. It is a mature oil field and the reservoir is fractured carbonate reservoir. After producing about 1% original oil in place (OOIP) reservoir pressure started to decline. Waterflooding was started in order to support reservoir pressure and also to enhance oil production in 1960. Waterflooding improved the oil recovery but after years of flooding water breakthrough at the production wells was observed. This increased the water/oil ratio at the production wells. In order to enhance oil recovery again different techniques were investigated. Chemical enhanced oil recovery (EOR) methods are gaining attention all over the world for oil recovery. Surfactant injection is an effective way for interfacial tension (IFT) reduction and wettability reversal. In this study, 31 different types of chemicals were studied to specify the effects on oil production. This paper presents solubility of surfactants in brine, IFT and contact angle measurements, imbibition tests, and lastly core flooding experiments. Most of the chemicals were incompatible with Garzan formation water, which has high divalent ion concentration. In this case, the usage of 2-propanol as co-surfactant yielded successful results for stability of the selected chemical solutions. The results of the wettability test indicated that both tested cationic and anionic surfactants altered the wettability of the carbonate rock from oil-wet to intermediate-wet. The maximum oil recovery by imbibition test was reached when core was exposed 1-ethly ionic liquid after imbibition in formation water. Also, after core flooding test, it is concluded that considerable amount of oil can be recovered from Garzan reservoir by waterflooding alone if adverse effects of natural fractures could be eliminated.