Microscopic sand production simulation and visual sanding pattern description in weakly consolidated sandstone reservoirs

To visually describe the sanding pattern,this study constructs a new particle-scale microstructure model of weakly consolidated formation,and develop the corresponding methodology to simulate the sanding process and predict sand cavity shape.The microstructure model is a particle-objective model,which focuses on the random sedimentation of every sand grain.In the microstructure,every particle has its own size,sphericity and inclination angle.It is used to simulate the actual structure of cemented granular materials,which considers the heterogeneity and randomness of reservoir properties,provides the initial status for subsequent sanding simulation.With the particle detachment criteria,the microscopic simulation of sanding can be visually implemented to investigate the pattern and cavity shapes caused by sand production.The results indicate that sanding always starts initially from the borehole border,and then extends along the weakly consolidated plane,showing obvious characteristic of randomness.Three typical microscopic sanding patterns,concerning pore liquefaction,pseudo wormhole and continuous collapse,are proposed to illustrate the sanding mechanism in weakly consolidated reservoirs.The nonuniformity of sanding performance depends on the heterogeneous distribution of reservoir properties,such as rock strength and particle size.Finally,the three sanding patterns are verified by visually experimental work.The proposed integrated methodology is capable of predicting and describing the sanding cavity shape of an oil well after long-term sanding production,and providing the focus objective of future sand control measure.

Early Description of Reservoir by Using a Single Well Data

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Donghe Sandstone Subtle Reservoir Exploration and Development Technology in Hade 4 Oilfield

Hade 4 oilfield is located on the Hadexun tectonic belt north of the Manjiaer depression in the Tarim basin, whose main target layer is the Donghe sandstone reservoir, with a burial depth over 5,000m and an amplitude below 34m, at the bottom of the Carboniferous. The Donghe sandstone reservoir consists of littoral facies deposited quartz sandstones of the transgressive system tract, overlapping northward and pinching out. Exploration and development confirms that water-oil contact tilts from the southeast to the northwest with a drop height of nearly 80m. The reservoir, under the control of both the stratigraphic overlap pinch-out and tectonism, is a typical subtle reservoir. The Donghe sandstone reservoir in Hade 4 oilfield also has the feature of a large oil-bearing area (over 130 km2 proved), a small thickness (average efficient thickness below 6m) and a low abundance (below 50 × 104t/km2). Moreover, above the target layer developed a set of igneous rocks with an uneven thickness in the Permian formation, thus causing a great difficulty in research of the velocity field. Considering these features, an combination mode of exploration and development is adopted, namely by way of whole deployment, step-by-step enforcement and rolling development with key problems to be tackled, in order to further deepen the understanding and enlarge the fruits of exploration and development. The paper technically focuses its study on the following four aspects concerning problem tackling. First, to strengthen the collecting, processing and explanation of seismic data, improve the resolution, accurately recognize the pinch-out line of the Donghe sandstone reservoir by combining the drilling materials in order to make sure its distribution law; second, to strengthen the research on velocity field, improve the accuracy of variable speed mapping, make corrections by the data from newly- drilled key wells and, as a result, the precision of tectonic description is greatly improved; third, to strengthen the research on sequence stratigraphy and make sure the distribution law of the Donghe sandstone; and fourth, with a step- by-step extrapolation method, to deepen the cognition of the leaning water-oil contact, and by combining the tectonic description and drilling results, to make sure little by little the law of change of the water-oil contact. The exploration and development of the Donghe sandstone subtle reservoir in Hade 4 oilfield is a gradually perfected process. From 1998 when it was discovered till now, the reservoir has managed to make a benign circle of exploration and development, in which its reserve has gradually been enlarged, its production scale increased, and, in a word, it has used techniques necessary for this subtle reservoir in the Tarim basin.

The Research and Applications of Remaining Oil Potential Tapping in High Watered Stage for Heavy Oil Reservoir in Bohai

S oil field is a typical of water injection development of heavy oil reservoir in Bohai, and the formation of crude oil viscosity is 42 - 284 mPa?s. Due to the formation of crude oil viscosity, the oil field development gradually faces a series of problems as rapid rise of water cut, rapid decline of output, high water cut of oil wells and others. In order to improve the effect of oilfield development, it is necessary to increase the output of the oilfield by adjusting wells for the potential in the oilfield. However, due to the high cost of drilling, operation and testing of offshore oilfields, offshore oilfields require more elaborate description of residual oil and adjustment wells. With the continuous downturn in international oil prices and the lack of new testing data in old oilfields, it is urgent to re-use the existing data in oilfields through innovative methods to achieve a detailed description of the remaining oil in the oilfields and improve the precision research of indexing wells and ensure the reliable implementation of adjustment wells. Based on the existing dynamic data of S oilfield, this paper proposes a new method to quantitatively evaluate water flooding coefficient by using tracer theory to establish tracer data, and quantitatively evaluates the vicinity of the fault by means of image reflection and potential superposition and find the residual oil in the imperfect area of the well network, combined with the numerical simulation method to realize the fine description of remaining oil and improve the research precision of the adjustment well. Through the research in this paper, S oilfield has proposed to location of six adjustment wells which has implemented two. The production confirmed that the method of this paper has some reliability, while the method of heavy oil in the high water cut stage of residual oil fine description. The research of enhanced oil recovery in the stage has certain guiding significance for heavy oil reservoirs.

An overview of efficient development practices at low permeability sandstone reservoirs in China

Low permeability sandstone reservoirs in China typically have more complicated geological conditions, pore structures, and flow characteristics as compared to medium-to-high-permeability sandstone reservoirs. Traditional geological and seepage theories, and engineering methods are not applicable to the development of these low permeability reservoirs, and wells drilled into them often produce oil and gas at very low rates. Recent breakthroughs in reservoir exploitation technology have greatly improved the productivity of low permeability reservoirs, making them the primary target for oil exploration and extraction in China. The development theories and practices applied to low permeability reservoirs in China are reviewed in this study— based on relevant geological and engineering practices, including drilling, fracturing, recovery, and surface engineering. A unique series of technological advances that aid the development of low permeability reservoirs in China are summarized here. This study may serve as a meaningful guide in achieving scale efficiency for the development of low permeability reservoirs.

油田开发中精细油藏描述成果平台建设研究

精细油藏描述是油田开发最基础的工作之一,历来受到研究者的高度重视。目前精细油藏描述中存在的突出问题主要包括研究成果继承性差、基础资料存储不规范、专业软件需求缺口大、成果应用需加强和成果存储管理不规范等5方面。文章通过精细油藏描述成果平台建设,可以从基础数据的整理准备、专业软件共享和协同研究、成果标准规范化存储管理等方面解决上述问题。精细油藏描述数据管理主要包括项目整体数据信息的统计和分析、项目研究数据的整理和统计、成果平台与其他数据平台的对接和数据调用等。精细油藏描述协同研究过程主要包括专业软件的平台实现和使用、不同专业软件之间中间成果的转换和调用、研究工作的自动化实现和完成。精细油藏描述成果存储和管理主要包括成果上传管理中格式的统一规范、成果存储上传中的质量控制、成果生产应用中的跟踪和更新。

中国石油《精细油藏描述技术规范》应用实践及发展对策

精细油藏描述是油田开发最基础的工作之一,历来受到研究者的高度重视。中国石油制定的企业标准《精细油藏描述技术规范》对于精细油藏描述标准化和规范化至关重要。详细介绍技术规范制修订背景,分析目前该技术规范还存在未被全面应用、内容要求执行不彻底、不同研究内容之间缺乏成因联系、研究成果提交不规范、精细油藏描述专项评价以定性为主、与国家、行业和企业标准结合不足等问题。建议加大《精细油藏描述技术规范》宣贯力度,严格按照规范各项要求开展工作,精细油藏描述坚持地质成因机制控制,严格规范提交各种成果数据体、数据表和成果图件,创建精细油藏描述研究过程及成果定量评价体系,加强与国家、行业和企业相关标准结合使用,不断提高精细油藏描述标准化和规范化水平。

胜利油田油藏描述技术回顾与发展方向

胜利油田为典型的陆相复式油气区,油藏类型多、含油层系多、断裂系统复杂,20世纪90年代初进入含水率为90%以上的特高含水开发阶段,如何针对不同类型油藏和开发阶段,精细刻画地下储层变化、精准认识剩余油,是实现高含水老油田提高采收率的基础。为此,从1996年始开展了针对老油田剩余油挖潜的精细油藏描述,通过精细储层构型表征、低序级断层精细描述、砂砾岩期次划分与连通性评价、薄互层滩坝砂储层预测、三维精细地质建模及剩余油精细描述等关键技术攻关,以及多轮次油藏描述技术迭代,形成了一套胜利特色的精细油藏描述技术,编制了精细油藏描述技术规范。截至2023年累计描述开发单元600余个,覆盖石油地质储量为43.6×108 t,建模数模技术在老区调整和新区方案编制中得到广泛应用,有效支撑了油田的规模建产与效益稳产。系统分析胜利油田油藏描述技术发展历程,总结不同类型油藏形成的特色技术,分析特高含水后期老油田精细油藏描述面临的5项挑战,阐述下一步油藏描述技术的5个发展方向,对推动陆相油田精细油藏描述技术具有指导和借鉴意义。

中国石油精细油藏描述技术新进展与展望

精细油藏描述研究是油田开发基础工作之一,其研究精度的不断提高,极大地促进了油田开发水平的提升。“十二五”和“十三五”期间,中国石油精细油藏描述研究针对多层砂岩油藏、复杂断块油藏、低渗透砂岩油藏、砾岩油藏、稠油油藏、特殊岩性油藏分别开展了技术攻关,形成了不同类型油藏配套技术系列。为了支撑剩余经济可采储量(SEC)储采平衡、老油田“压舱石”、采收率再提高、页岩油革命等“四大工程”,系统梳理中国石油精细油藏描述研究在5个方面的最新进展,分别是井震结合构造精细解释技术实现低级序断层定量描述,基于储层构型研究的单砂体刻画技术实现米级砂体描述预测,室内实验、数字岩心、物理模拟和数值模拟等方法技术实现综合剩余油表征,精细油藏描述成果平台建设实现研究过程协同共享和成果规范化存储管理,建章立制制定系列标准规范实现精细油藏描述研究规范化。通过系统总结精细油藏描述存在的8个方面问题,提出精细油藏描述的发展方向。

火山岩气藏勘探开发理论技术与实践——以松南断陷白垩系火山岩为例

近20年来,中国石化东北油气分公司在松辽盆地南部的勘探进一步证明,盆地火山岩是寻找油气藏的新靶区,具有广阔的前景。东北油气分公司根据盆地勘探实践,总结了以主成藏期为关键点的“生烃灶-成藏期古构造-断盖保存-有效储层”联动演化的断陷层四元耦合控藏模式,推动了松南地区长岭断陷火石岭组大规模火山岩气藏的发现。火山岩勘探方向从营城组拓展到更深层的火石岭组,勘探目标从酸性火山岩拓展到中基性火山岩,从水上喷发到水下喷发。采用气藏精细描述技术,建模数模一体化及地质工程一体化技术,在松南断陷多口井取得产能突破,实现火山岩气藏高效开发和规模上产。

Y油田低渗透油藏高含水阶段提高采收率研究

低渗透砂岩油藏储量丰富,约占全国储量的2/3以上,开发潜力巨大。该类油藏具有孔渗条件差、储层非均质性强、吸水能力差等特点,开发后期油藏进入高含水阶段,存在水驱效果差、开发难度大、采收率较低等问题,因此亟需探究提高采收率的有效手段。以Y油田低渗透油藏为例,在地质模型和精细油藏描述的基础上,通过生产动态分析和剩余油表征,针对全区水驱储量控制程度低、油井含水高、注采井网不完善的问题,提出了精细注水、注气和水气交替等措施。通过数值模拟方法,对比不同措施的开发效果,优选最佳方案,预测实施调整方案15年后,全区采收率提高12%。该研究成果可为低渗透砂岩油藏高含水期的高效开发提供参考依据和借鉴。

沾化凹陷垦西斜坡带沙河街组三段下亚段沉积特征及有利储层预测

垦西斜坡带构造处于沾化凹陷中部,孤岛潜山西南倾末端,西北为渤南洼陷,南边过垦西断层为三合村洼陷,是由孤西断层与一组近东西向垂直于孤西断层的断裂构建的“梳状断裂构造带”。研究区沙河街组三段下亚段油气充足,深部储层只要位于沟通油源的通道处,均有可能成藏。但早期研究认为该区沙河街组三段下亚段沉积类型为远源的三角洲水道沉积.

胜利油田低渗透油藏开发技术进展及展望

胜利油田低渗透油藏资源丰富,已探明石油地质储量达11.8×10^(8)t,具有良好的开发前景。但低渗透油藏由于具有孔隙度低、储层非均质性强和渗流能力差的特点,在开发过程中存在“注不进、采不出”的问题。为实现低渗透油藏高效开发,系统梳理了胜利油田低渗透油藏储层预测分析方法以及高效开发技术,并结合现有技术的优缺点对低渗透油藏开发技术方向进行展望。通过研究与实践得到:①胜利油田通过攻关,研究形成了储层预测、地应力预测以及储层非均质性评价等精细油藏描述技术。②通过理论技术创新,不断突破储量动用物性下限,攻关形成了特低渗透油藏仿水平井注水开发技术、致密油藏长井段多级压裂水平井开发技术、一般低渗透油藏井网适配提高采收率技术、低渗透-致密油藏压驱开发技术和增黏型乳液-表面活性剂驱开发技术等差异开发技术系列,取得了良好的开发效果。③结合胜利油田低渗透油藏高质量发展及提速提效开发的实际需求,提出了双控转流线井网重构技术、CCUS技术和纳米气泡水驱技术,为低渗透油藏提高采收率指明发展方向。

Fine description of unconventional clastic oil reservoirs

The latest researches reveal that studies on unconventional clastic oil reservoirs in China generally lag far behind those in other countries in respect of content and methodology.This study presents the definition and classification of unconventional oil reservoirs and analyzes the problems in the fine description of unconventional oil reservoirs.The key content of the fine description of unconventional oil reservoirs is summarized from four aspects:fine fracture characterization based on fine structure interpretation,reservoir architecture characterization based on sedimentary facies,characteristics of nanoscale microscopic pore structure of reservoir,and evaluation of source rock and“sweet spot zone”.Finally,this study suggests that development of fine description of unconventional clastic oil reservoirs in the future should focus on rock brittleness analysis and fracture modeling,geophysical characterization of unconventional clastic oil reservoirs,fluid description of tight reservoirs,and physical/numerical simulation experiments of unconventional oil reservoirs.

复杂断块油藏滚动增储关键技术

PL油田为大型复杂断块油田,主要含油层位为新近系明化镇组和馆陶组,储层受浅水辫状河三角洲、曲流河沉积控制。该油田经过20年的开发,已进入双高阶段,寻找优质接替储量,保证稳产上产成为油田开发的主要矛盾。开发实践证明,油田边部断块油底之下潜力受制于控藏断层的封闭能力;开发老区潜力分布在隐性断层控制的正向微构造单元,受断层开启性和隐性断层双重因素控制.

海相砂岩油藏定量描述技术及开发策略——以文昌Z油田为例

文昌Z油田经过二十年的开发,层内层间物性差异大,大部分生产井采用多井合采方式导致剩余油分布较为复杂,定量描述剩余油难度大。以Z油田ZJ1-4U油组为例,利用地质精细描述、剩余油定量描述及时变数值模拟,对剩余油分布进行精细研究,形成一套海相砂岩油藏剩余油定量描述的研究技术。通过油藏剩余油定量描述研究技术,挖掘油田内部潜力,提出加密调整方案,投产后取得良好效果,表明海相砂岩油藏定量描述技术可实施性较高,为类似油藏下步挖潜提供新方法新思路。

油藏描述特征及新技术研究进展

本文旨在针对油藏描述研究的广泛性,探讨油藏描述的概念、特征、技术应用优势和存在问题,并提出解决思路和发展趋势。同时,本文对于重新界定油藏描述和储层表征等概念具有一定的参考价值。

层状断块油藏特高含水期细分开发技术

辛 4 7断块是一个高丰度的层状断块油藏 ,采用分层系注水开发。在同套开发井网内 ,由于受非均质的影响 ,层间水驱状况不均衡。 1999年 ,断块进入特高含水期后 ,层间矛盾加剧 ,原有开发层系和井网已不适应油藏挖潜需要。 2 0 0 0年 ,在辛 4 7断块开展了精细油藏描述和细分开发工作 ,效果非常明显 ,断块含水下降了 3% ,采油速度提高了 0 38% ,采收率提高了 5 %。实践表明 ,采用精细油藏描述和细分开发的技术方法 ,对提高层状断块油藏水驱采收率是行之有效的。

大庆徐深气田火山岩气藏储集层识别与评价

松辽盆地徐深气田具千亿方天然气储量规模,其中火山岩储集层储量占89.8%,但其勘探开发水平受火山岩气藏储集层识别和描述水平的制约。为此,通过多学科联合攻关形成了一套适用于火山岩气藏的储集层识别及描述技术。徐深气田有八大类21种火山岩岩性,测井可识别10种;火山岩岩相有5种,细分为15种亚相。有利储集层的岩相、岩性为:喷溢相上、下部亚相的气孔流纹岩,爆发相热碎屑流亚相的晶屑凝灰岩、火山通道相隐爆角砾岩亚相的角砾岩、火山通道相火山颈亚相的熔结角砾凝灰岩、侵出相中带和内带亚相的球粒流纹岩。储集层有效储集空间由气孔、溶蚀孔洞、裂缝有机组合构成。应用新建立的火山岩气藏储集层分类标准,结合试气试采动态特征和产能分类,采用动、静态结合的评价方法,对徐深气田火山岩储集层进行了综合评价,根据储量丰度、储集层发育状况、产能高低和认识程度将储量分布区分成一类、二类、三类区块。