Experimental investigation on using CO_(2)/H_(2)O emulsion with high water cut in enhanced oil recovery

CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility reduction.However,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely researched.In this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil recovery.Firstly,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT cell.Subsequently,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary tube.Furthermore,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were analyzed.The results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) emulsion.An inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was confirmed.CO_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water cut.Eventually,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,respectively.This work may provide guidelines for EOR using CO_(2) emulsions with high water cut.

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 lowefficiency loells,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.

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.

浅水受限区水下油气田开发方案

针对国内浅水油气资源开发环境影响及空间受限等问题,本文提出了国产浅水水下生产系统的总体设计方案。通过对浅水水下生产系统关键设备结构进行分析,提出了一种满足受限区海域开发要求的环境友好型设计思路。结果表明:通过系统和总体布置的设计,国产浅水水下生产系统与深水相比在单体重量、作业方式、维护检修方面更加经济。

考虑颗粒充填的水平井控水完井产量预测方法

近年来在水平井管柱与井眼环空进行颗粒充填的控水方法在底水油藏得到了广泛的应用,目前尚没有准确的产量预测方法。为此,从宏观流动与微观流动的差异性入手,分析了流体在底水油藏、颗粒充填层、控水工具等不同空间维度内流动之间的相互关系,在油水两相数值模拟模型的基础上,采用“矩阵镶边”的方法将3个维度的流动模型相互耦合,提出了考虑颗粒充填的水平井控水完井产量预测方法,准确度比常规等效方法提高9.17%。研究结果表明,新方法能够实现流体在油藏、颗粒充填层和控水工具间窜流量的定量求解,更直接地体现不同空间维度流动对控水效果的影响,为底水油藏考虑颗粒充填的水平井控水完井产量预测提供了有力工具。

AICD筛管充填控水技术及应用

海上某油田砂体分布复杂,同时受气顶和边水的影响,无法发挥水平井的产能。针对该油田防砂、控水的双重需求,提出了采用AICD控水筛管配合环空充填覆膜颗粒的控水完井工艺技术,详细介绍了AICD充填控水技术的控水原理、管柱设计方法和充填规律。实际投产结果表明AICD筛管配合覆膜颗粒充填技术可以使油井保持稳定的低含水生产状态,降水增油效果显著,适用于渤海油田非均质性较强的油藏。研究的管柱设计方法和充填规律为海上油田水平井控水完井设计提供了参考和借鉴。

基于油井动液面测控自适应采油系统应用

为了最大程度的发挥油藏的开采潜力,根据回声测深原理和自适应测控采油原理,研发油井动液面测控自适应采油系统,远程控制在线液面测试仪,实时监控油井动液面,根据生产实际需要,计算生产参数,合理选用快抽、慢抽、间抽三种控制模式,保障动液面的合理沉没度。同时提高泵效,减少无用功,达到节能增产的效果。2023年在胜坨油田不同工况的24口采油井试验,每年节电145257 kWh,增产油量8033.4 t,同时减少单井用工,实现高效节能增产的目标。

连续封隔体控水技术在南海东部油田的应用效果

在水平井开发生产过程中,由于局部高渗段、水窜裂缝、油水粘度差异等因素导致的产液剖面不均衡,从而引起油井高含水。连续封隔体控水技术在南海东部应用取得了一定的控水增油效果,为了提高连续封隔体控水技术应用性,分析了连续封隔体控水技术在南海东部的应用效果,为后续选井提供参考。

三叠系油藏堵驱结合技术的探索应用

针对胡尖山油田三叠系油藏储层非均质性强、注入水波及范围小、驱替效率低且多轮次调剖调驱效果减弱等问题,以H4区油藏为研究对象,基于前期矿场试验效果,优选近井调剖封堵体系与纳米微球深部调驱体系相结合,充分发挥协同治理优势。结果表明,堵驱结合技术在非均质油藏中具有较好的控水增油适应性,对应油井见效率、含水率下降幅度、平均单井增油量均优于单一体系,为同类型油藏调剖调驱体系组合优化提供借鉴参考。

海上高含水油田示踪监测控水技术及应用

针对海上高含水油田在完井之后无法实现精准找水、控水的难题,将微量元素示踪监测技术与机械控水技术结合,形成示踪监测控水技术,并进行了现场应用。结果表明,该技术可在满足稳油控水需求的基础上,实现对海上高含水油田生产井不动管柱产液剖面在线监测;通过在井口取样分析示踪剂的浓度,无需改变生产制度,即可定量计算出各个层段的油水动态变化及产液贡献;可精准识别见水时间及主力见水位置,有利于优化油田生产制度,实现精准找水,提高稳油控水技术的针对性。研究及应用结果为此类高含水油田的治理提供了借鉴。

海上中心油田生产水处理系统仪控技术优化研究及应用

生产水处理系统是海上油田产能的核心系统之一,针对海上某中心油田生产水系统运行中出现的主要问题,该油田通过对仪控系统的优化改造,开发“油井一键降频及关停技术”“干扰滤波”“在线旁通”技术,应用“数据远程通信共享技术”,不但有效解决了系统存在的问题,实现了可观的经济效益,还全面提高了全寿命周期设备的可靠性,为实现定量的预知性维修铺平了道路,为今后同类设施、设备的操作和运维探索及研究提供了借鉴。

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.

特高含水油藏剩余油分布特征与提高采收率新技术

渤海湾盆地胜利油区经过60多年开发,整装、断块油藏已处于特高含水开发阶段,含水率超过90%,稠油油藏进入高轮次吞吐开发阶段,整体采出程度不到40%,仍有大幅度提高采收率的潜力,需要攻关进一步提高采收率技术。针对整装油藏特高含水后期高耗水层带发育、低效水循环严重,断块油藏剩余油分布差异大、有效动用难度大,深层、薄层超稠油注汽难、热损失大,有碱复合驱油体系结垢严重,聚合物驱后油藏动态非均质性更强、剩余油更加分散以及特高含水后期套损井多、出砂加剧、精细分层注采要求高等难题,明确地质及剩余油分布特征,深化驱油机制认识,围绕整装油藏经济有效开发、断块油藏高效均衡开发、稠油油藏转方式开发、高温高盐油藏化学驱开发开展技术攻关,形成整装油藏精细流场调控技术、复杂断块油藏立体开发技术、稠油油藏热复合驱提高采收率技术、高温高盐油藏化学驱技术、特高含水期主导采油工程技术等特高含水油田提高采收率技术系列,开辟先导试验区,取得显著开发效果,实现工业化应用,支撑胜利油区持续稳产。

高含水期油藏剩余油聚集度表征方法

剩余油聚集度是评价高含水期油藏开发效果及开发潜力的重要指标。通过剩余油储量丰度,确定油藏优势储量区;利用单块面积、分布密度和形状指数,通过熵权法确定各指标的权重,最终形成剩余油聚集度的表征。研究表明,对于一个稳定开发的油藏,开发过程中剩余油的离散与聚集可分为一次离散阶段、迅速分离阶段、波动聚集与离散阶段和二次离散阶段。利用表征指标对大港油田港东开发区二区七断块Nm3-4-1小层进行评价,该小层剩余油聚集度随着开发的进行稳步下降,现阶段由于注采结构和井网调整,剩余油聚集度开始上升。

基于卷积神经网络和迁移学习的特高含水油井生产预测

油井的实时生产监测对油田的辅助生产和精细化管理有重要意义。然而,针对仅有小样本生产数据、数据波动大且有缺失的特高含水期油井,传统的机器学习算法无法实现良好的生产预测。提出一种基于卷积神经网络和迁移学习的多任务生产预测方法。该方法不仅可以实现时间和空间上特征的自适应提取,还可以改善模型在小样本数据上的预测性能。结果表明:相比于基准模型,产液量和动液面的平均绝对误差分别降低31.26%和60.81%,决定系数分别提高1.89%和7.59%。基于迁移学习的MTCNN模型提高小样本数据油井的生产预测精度,实现了特高含水油井产液量和动液面的实时预测,对抽油机系统的效率优化、油井边缘设备智能化有参考意义。

不同注采方式下层间非均质储层微观剩余油动用状况

特高含水期强非均质性油藏注水开发一直是油藏工程中重点研究的问题之一,而研究该问题的核心是明晰剩余油的分布、类型及启动方式。为了明确不同注采方式条件下微观剩余油的赋存状态,利用微流控驱替实验,针对强非均质性储层,对不同注采方式下微观剩余油进行动用状况定量化研究。储层中微观剩余油的主要分布类型以簇状流为主,柱状流和多孔流次之,滴状流基本没有赋存;基于微观剩余油定量分析,明确了不同注采方式对特高含水期强非均质性储层剩余油采出程度的提高效果,其中轮注轮采对该体系提升最大,分注轮采次之,轮注合采最差;并进一步研究了不同类型的注采方式在微观驱替时主要作用的剩余油类型及其作用机理。研究成果为该类型储层注水开发过程中注采方式的选择提供了理论依据。

渤海C油田预钻井原油乳化对储层伤害实验研究

渤海C油田导管架期间首批12口预钻井在生产过程出现了生产压差高产量低的现象,分析认为原油乳化堵塞是潜在伤害因素。为了明确原油乳化堵塞机理,为产能恢复措施制定提供指导,针对该批低产井开展原油乳化堵塞实验研究。实验结果表明:当含水率为20%时,原油乳状液黏度为最高值10.9 mPa·s,为原油乳化反相点,乳状液类型为油包水(W/O)型;当含水率大于20%时,乳状液黏度降低,类型为水包油(O/W)型;原油高含水时,乳状液类型为O/W型,降低储层渗透率25.21%,对储层伤害相对较小;原油低含水时,乳状液类型为W/O型,降低储层渗透率75.01%,对储层伤害大。随着乳状液质量浓度从1000 mg·L^(-1)增加至4000 mg·L^(-1),岩心渗透率伤害程度最高达到50%。以I01H和I28H井为例,结合实验结果对实际生产动态进行分析,两口井生产初期含水率升高至20%后,生产压差不变,采液指数下降,说明原油发生乳化并堵塞近井地层,与实验结果一致。

高孔高渗高含水稠油油藏剩余油分布特征及动用的主控因素

针对CFD11-1油田943砂体大量剩余油无法动用的问题,结合动态数据和生产数据,将注入流体、地层倾角、渗透率韵律和级差4种因素进行数值模拟,对油藏剩余油分布类型以及影响海上高孔高渗油藏剩余油动用的主控因素进行分析。结果表明:1)高孔高渗高含水稠油油藏的剩余油分布类型可分为油藏边缘井网未控制、井间未控制、相对低渗绕流和构造高部位4种;2)注入流体是影响不同类型剩余油动用的首要因素,说明注入流体优选和有效波及仍是未来提高海上油藏采收率的主要方向之一。注入流体与不同剩余油类型的结合应兼具经济性和环保性,例如构造高部位的气驱与活性水相比仅降低1.59个百分点;3)相比于气驱,活性水驱扩大平面波及效率,有效减弱指进效应,边部剩余油井组采出程度提高了12.88个百分点;4)剩余油动用敏感性因素分析显示,注入流体和地层倾角是影响采出程度的主控因素,受油藏高孔高渗影响,渗透率韵律和级差已经不是限制流体流动的主要因素,其对采出程度的影响不超过1%。该研究成果对海上高孔高渗稠油油藏的高效开发有一定的指导作用。

中高含水率期油藏薄互层状剩余油动用技术

受储层非均质性影响,注水开发油藏经过长期注水冲刷形成水流优势通道,导致油井过早水淹,但仍有大量剩余油呈薄互层状赋存。中高含水率期提高采收率的核心就是如何动用这部分剩余油,本文在立足单砂体剩余油精细刻画基础上,根据单砂体剩余油控制因素及分布特征,通过注采结构优化调整、微球调驱及气驱提高采收率技术,有效改善了驱替效果,增加了可采储量,预测提高采收率3.00%。