Abstract For many oil fields, due to the limitation of economic benefits or short development history, there are many difficulties, such as fewer cores, larger spacing of cored wells and poor seismic data quality, etc. This paper takes a giant carbonate reservoir in H oilfield as an example, utilized common reservoir monitoring data, namely PLT and tracer detection data, to assist sedimentary facies research and get more convincing results in both deposition understanding and facies model. The new procedure of deposition study and facies modelling were introduced as follows: Firstly, with comprehensive geological data, the sedimentary facies study was conducted and the initial sedimentary facies maps were made; Secondly, the PLT data and tracer detection data were collected and analyzed; Thirdly, reservoir monitoring data were utilized to improve the initial sedimentary facies understanding. Finally, the sedimentary facies maps were redrawn and used to constrain facies modelling and a few realizations of facies models that complied with the geological knowledge were got. They are for the geologists and the reservoir engineers to choose the right realization together. Then the sedimentary facies maps were redrawn and used as trend to constrain facies modelling, which show better coincident rate between static and dynamic data. With the continuous reservoir development, the amount of reservoir monitoring data is gradually increasing, and the corresponding geological research is increasingly deepening. The new facies model was more in line with the actual underground conditions of the reservoir and laid a solid foundation for other workflows in the static and dynamic process of reservoir study. Without changing other parameters, the history match results improve significantly, which lays solid foundation for reservoir management.

Based on the waterflooding development in carbonate reservoirs in the Middle East, in order to solve the problem of the poor development effects caused by commingled injection and production, taking the thick bioclastic limestone reservoirs of Cretaceous in Iran-Iraq as an example, this paper proposes a balanced waterflooding development technology for thick and complex carbonate reservoirs. This technology includes the fine division of development units by concealed baffles and barriers, the combination of multi well type and multi well pattern, and the construction of balanced water injection and recovery system. Thick carbonate reservoirs in Iran-Iraq are characterized by extremely vertical heterogeneity, development of multi-genesis ultra-high permeability zones, and highly concealed baffles and barriers. Based on the technologies of identification, characterization, and sealing evaluation for concealed baffles and barriers, the balanced waterflooding development technology is proposed, and three types of balanced waterflooding development modes/techniques are formed, namely, conventional stratigraphic framework, fine stratigraphic framework, and deepened stratigraphic framework. Numerical simulations show that this technology is able to realize a fine and efficient waterflooding development to recover, in a balanced manner, the reserves of thick and complex carbonate reservoirs in Iran and Iraq. The proposed technology provides a reference for the development optimization of similar reservoirs.

Pressure gradient method is based on the principle of connectedness, using formation pressure test data to character pressure gradient curves of reservoir fluids and distinguish oil water contact. The greatest advantage of this method is Intuitive identification of oil and water contact depth. It provides basis for fine reservoir description and progressive exploration and development. According to the data of single well test, the regional water pressure curve is fitted. The difference between the hydrostatic pressure curve and the hydrostatic pressure curve is defined as the overburden pressure. The depth of test point and test pressure, formation water density and crude oil density are established to calculate the depth of oil-water contact. Well Che 47 Block, because of many times of vertical volcanic cycle, complex lithology and lithofacies, and strong heterogeneity of secondary reservoirs, multiple lithologic shielding bodies can be identified. By using the pressure gradient method and combining the reservoir geological characteristics of the industrial area, it is revealed that at least 3 relatively independent reservoir units in the Well Che 47 Block, and the corresponding depth of oil-water contact is −2786 m, −2848 m and −2912 m respectively. According to the relationship between the depth of the oil and water contact and the position of the test point, it is conservative to predict that the lowest oil layer is at least 200 m of the oil column height, and the prospect of rolling is good. The application of the pressure gradient method to identify the oil-water interface in complex reservoirs is more in line with the actual underground conditions. This method, combined with seismic and log data, can provide an important basis for the fine evaluation of complex volcanic reservoirs.

The Cenomanian–Early Turonian Mishrif Formation is a great contributor to oil production in Iraq. Integrating petrographic, mineralogical, and wireline logging data from 52 wells, this study provides an improved understanding of the sequence stratigraphy, depositional evolution, and reservoir characteristics of the Mishrif Formation in the Mesopotamian Basin, south Iraq. Five types of facies associations are classified: lagoon, shoal, rudist bioherm, shallow marine, and deep marine. Such a classification allows convenient differentiation and interpretation of wireline logs. A sequence stratigraphic framework including five third-order sequences (Mhf 1 to Mhf 5) for the Mishrif Formation is established mainly using wireline logging data of close-distance wells, with the aid of cores and thin sections. Two end-member depositional evolution stages are recognized, from clinoform-like progradational shoal complexes in Mhf 1 within a shallow marine environment, to tidal channels in Mhf 2–3 within a lagoon environment. For Mhf 4–5, abrupt changes in facies associations from north to south indicate the development of an intra-shelf basin where organic-rich mudstones directly overlie the shallow marine grainstone shoals and lagoonal wackestones. Reservoir characteristics and compartmentalization are directly controlled by the sequence stratigraphic framework. Sequence boundaries are featured by wackestones and mudstones overprinted by cementation; they are regionally correlatable and work as regional barriers. Shoal complexes in Mhf 1 and tidal channels in Mhf 2–3 are the main reservoir units. Mudstones and wackestones are intra-reservoir baffles and become more frequently developed towards the south, reflecting the increasing water depth towards south. The characterization of the tidal channels, clinoform-like shoals, and intrashelf basinal deposits in the current study could benefit later development of the Mishrif Formation.

油藏开发实时优化调控技术是智能油藏研究的核心内容.提出了基于数据空间反演的油藏实时生产优化新方法,仅需若干油藏模型先验生产动态,基于贝叶斯理论构建代理模型,根据随机极大似然原理拟合历史观测数据进行模型训练,反演得到符合实际观测数据的生产动态后验估计.采用同步扰动随机逼近算法建立生产优化数学模型,实现注采参数实时优化,提高经济开发效益.该方法基于代理模型在拟合阶段避免了重复数值模拟计算,得到正确生产动态后验估计同时兼顾了油藏模型实际地质特征,优化所得方案考虑了目标油藏的不确定性,降低了实际生产开发风险.油藏实例应用表明:该方法能得到与常规多模型数据同化方法相一致的生产动态预测结果,拟合过程计算效率提高了5倍,且注采优化方案能取得良好的驱油效果.提出的油藏开发生产优化设计方法为油田实时生产优化提供了新的思路.

拉萨地块林周盆地下白垩统塔克那组沉积于新特提斯洋壳向拉萨地块俯冲的弧后伸展环境,对重构该时期古地理格局、理解活动陆缘伸展构造对沉积的控制作用具有重要意义.基于野外露头描述和薄片观察,总结塔克那组岩石地层、岩石学和古生物特征,对比同期新特提斯被动陆缘阿拉伯板块Shu'aiba组,讨论塔克那组沉积演化和活动陆缘沉积特征.塔克那组发育碎屑岩、硅质碎屑-碳酸盐混积岩、碳酸盐岩三大类沉积岩十种岩石类型,纵向上划分为四个岩性段,是一个三级相对海平面变化旋回的沉积层系.塔一段砂岩—混积岩—灰岩岩性变化、沉积构造和生物类型均指示潮间-潮下带潟湖环境;塔二段沉积于海平面快速上升期,主要为风暴浪基面之下厚层泥灰岩;塔三段在玛行西剖面首次识别出代表风暴浪基面之上的风暴成因生物富集层,往西南在甲绒东剖面相变为浅滩相生屑/鲕粒颗粒灰岩;塔四段沉积期海平面持续下降,海水逐渐退出盆地,沉积滨岸和泛滥平原环境的泥页岩夹粉砂岩.与阿拉伯板块同期生物种属对比表明,塔克那组沉积期,南拉萨地块林周盆地与新特提斯洋沟通性好.活动陆缘伸展背景下,具有基底快速差异沉降、陆源沉积物持续输入的特征,导致纵、横向相变快,混积岩发育,厚壳蛤、Lithocodium-Bacinella等浅海喜净水生物和深水浮游生物欠发育.

通过R油田多口取心井岩心、薄片、碳氧同位素、测井曲线等资料的综合分析,厘清了 Mishrif组碳酸盐岩不同级别、不同类型层序界面的识别特征,以及在层序界面控制下早成岩作用对储层的影响.研究表明:R油田Mishrif组属于二级层序海退半旋回上部,可细分为1.5个三级层序(S1,S2)及5个四级层序(FS1-FS5).其中,三级层序S1为一个海退半旋回,S2为一套完整的海进海退旋回,其顶界同为二级层序界面.识别了 3种四级层序界面类型,分别为中期地表暴露型、短期地表暴露型和水下硬底型,三级层序界面为中长期间歇暴露硬底型,二级层序界面为长期地表暴露型.不同类型层序界面沉积与早成岩特征各不相同,造成了油藏内部结构和储层品质的变化.因此,层序格架建立及其层序界面差异早成岩特征研究可为储层成因分析与油藏地质建模提供基础.

The study on the flow behaviors of oil and water two phases in porous media and their influencing factor is very important to adjust the porous carbonate reservoir development strategy and enhance the oil recovery. Based on the CT (computed tomography) scanning of real carbonate reservoir core sample, the micropore structure was reconstructed, and the effects of different factors (injection rate, oil-to-water viscosity ratio, and contact angle) and secondary development methods (higher injection rate and water displacement direction optimization) on the flow behavior of oil and water two phases were explored by numerical simulation in this paper. It is found from the study that the pores in the porous carbonate reservoirs have good structural connectivity. During the displacement process, the oil-water interface mainly resides at the pore throat junction with a large change of pore size, and the Haines jumps exist in the oil-water movement; the areal sweep efficiency of the water phase is jointly affected by the viscosity effect, interfacial tension, pore structure, and injection rate. Under the minimum injection rate and oil-to-water viscosity ratio, the maximum oil recovery can be obtained, and the oil recovery is 52.62% and 57.01%, respectively. The recovery efficiency and swept area are better in a water-wet system than oil-wet system. During the secondary development, the remaining oil is hardly displaced even with the injection rate increased by a factor of 50, and it shows improvement after 250 times of initial injection rate. Changing the position of water inlet and the produced fluid outlet results in better recovery since the remaining oil near the new inlet and outlet can be effectively produced.

A significant behavior of carbonate reservoirs is poor correlation between porosity and permeability. With the same porosity, the permeability can vary by three orders of magnitude or more. An accurate estimation of permeability for carbonate reservoir has been a challenge for many years. The aim of this study was to establish relationships between pore throat, porosity, and permeability. This study indicates that pore throat radius corresponding to a mercury saturation of 20% (R20) is the best permeability predictor for carbonates with complex porous pore networks. Quantitative analysis was made to achieve three different patterns of pore throat for 417 carbonate samples which cover all pore types of carbonate rocks. Different relationships between porosity, pore throat radius, and permeability have been identified in different patterns, which are utilized to predict more accurate permeability by different pore throat patterns.

Beach-bar deposit is a typical sedimentary system in the shore shallow lake sedimentary environment, which is mainly composed of thin interbedded deposits. In recent years, with the exploration of lithologic reservoirs, it has gradually become the focus of geologists. Around the combination characteristics and difficulties in hydrocarbon accumulation of the beach-bar in Tanan depression, this paper studies the sedimentary characteristics and distribution rules of beach-bar sand in the period of Tongbimiao formation in Tanan depression, and makes clear the accumulation model and enrichment rules of beach-bar sand reservoir in Tongbomiao formation. The results show that the beach-bar sand in Tongbomiao formation of Tanan depression is mainly of two genesis: the beach-bar sand of the lateral margin formed by the modification of the front edge of the delta sedimentary system by the lake waves and formed by the control of the basement paleouplift, and the distribution morphology is mainly controlled by the palaeowind direction and palaeogeomorphic during the sedimentary period. The accumulation model can be divided into the composite accumulation model of “source reservoir integration” and the lateral accumulation model of “source-reservoir docking”, which are respectively developed in the near-source sag and the middle of ancient slope zone. The research results have certain guiding significance for the accurate development of Tanan oilfield.

碳酸盐岩储层非均质性极强,孔喉结构复杂,且孔隙度与渗透率相关性差.中东地区白垩系Mishrif组发育典型的孔隙型碳酸盐岩储层,相同孔隙度条件下渗透率相差达3个数量级,给准确评价该类储层的渗透能力以及合理的储层分类带来了极大挑战.为深入分析中东地区Mishrif组孔隙型碳酸盐岩储层渗透率的主控因素,基于M油田415个高压压汞实验样品数据统计对比,明确了研究区Mishrif组碳酸盐岩储层具有多种模态并存的孔喉结构特征,其中单模态孔喉结构储层的孔渗相关性明显好于双模态和多模态孔喉结构储层;进而对孔喉结构特征参数进行定量分析,明确多模态孔喉结构碳酸盐岩储层孔隙度和渗透率随孔喉结构参数变化的规律.研究表明,汞饱和度为20％对应的孔喉半径(R20)与渗透率的相关性最好,将R20作为特征孔喉半径与孔隙度和渗透率进行相关性分析发现,随着孔喉半径的增加,孔隙度先线性增加,至一定程度后维持稳定不再增加,与之形成对比的是随着R20的增加,渗透率持续增加.

基于岩心、测井、薄片、阴极发光等资料,系统梳理了中东地区X油田Mishrif组生物碎屑灰岩的主要岩石特征、岩相类型以及各岩相差异成岩作用特征与序列、多期白云岩化作用特征与其成因模式,并分析了各成岩作用对储层品质的差异控制.研究结果表明:根据生屑类型与结构特征将X油田Mishrif组生物碎屑灰岩分为12种岩石类型以及5大类岩相类型,其经历溶蚀、胶结、白云岩化、压实以及压溶等多种成岩作用.对比区分各岩相差异成岩作用类型与强度,并着重分析多期次大气淡水胶结、海水胶结作用、地层水胶结作用以及白云岩化作用发育特征与相互次序.研究区生物碎屑灰岩发育早、中、晚3期4种白云岩化作用,通过对不同岩相白云岩化产物特征分析认为,早期第1种白云岩化作用为回流渗透白云岩化作用,早期第2种为混合水白云岩化作用,中期、晚期为埋藏白云岩化作用,并对混合水白云岩化作用成因模式进行探讨.在对储层品质差异控制方面,部分岩相早期生屑颗粒间的胶结作用有助于孔隙的保存,有利于储层品质提高;早期白云岩化作用一般有利于局部渗流能力的增强,晚期白云岩化作用形成的白云石占据储层残余空隙,降低储层品质.

Paleogeomorphic restoration plays an important role in sedimentary basin research which has a great geological significance of establishment the sedimentary system and understanding of hydrocarbon accumulation rules. Based on 3D seismic data, drilling data and core data, this paper quantitatively restored paleogeomorphology of Tongbomiao formation in Tanan depression of Haita basin from two aspects of tectonic recovery and sedimentary recovery, and clarified the paleogeomorpholog controlled sedimentary system and oil and gas distribution. This paper indicates that ① the sedimentary period of the Tongbomiao formation has the characteristics of “extensive troughs and multi-sources sediment”, The source is mainly the fan delta in the direction of NW-SE and WS and the paleo-uplift in the depression; that ② the sedimentary period of the Tongbomiao formation main developing alluvial fan, nearshore underwater fan, fan delta and coastal shallow-lake facies, the formation and distribution of alluvial fan were controlled by the ancient uplift in the depression; and that ③ The source faults and the paleogeomorphology features controlled the regular of oil and gas accumulation, the oil migrated by faults in the direction of NE, and the further migration to the north of Tanan depression is the resulted of paleogeomorphology characteristics which is “lower from north to south, lower from west to east”, and oil accumulated in the midwest of the depression.

白垩系Mishrif组是伊拉克南部碳酸盐岩主力产层,属于典型的碳酸盐缓坡沉积,其中内缓坡高能滩相是优质储层最发育的部位.通过对伊拉克南部多个油田资料深入分析,发现Mishrif组中普遍存在有潮道沉积特征的优质储层,且多数潮道沉积在过去被当作另一种滩相沉积.笔者综合大量的岩心、铸体薄片、测井以及地震资料分析后,证实这部分储层为潟湖环境中潮道沉积,其分布广泛,是具有代表性的沉积亚相.潮道沉积岩石颗粒分选、磨圆较好,发育层理构造,粒级向上表现为正韵律或均质特征,对应为"钟形"或"箱形"测井响应特征以及弱波峰夹层地震响应特征,平面上呈北东-南西向条带状分布,整体上表现为由北东向南西迁移的特征.该研究说明碳酸盐岩地层中也发育成规模的潮道沉积,对缓坡背景下沉积模式研究是重要发现和补充.碳酸盐缓坡潮道的认识也为储层预测提供了新思路,进而为该类油藏开发方案设计与调整提供地质基础.

Due to the severe heterogeneity of carbonate reservoirs, the traditional reservoir engineering methods for waterflooding performance forecast, mainly including the material balance equation, waterflooding characteristic curve and production decline curve, suffer from less reliability. The fine-scale reservoir numerical simulation is extremely time-consuming, because petrophysical properties in carbonate geological models change so drastically. To predict the development performance rapidly, a new method for large-scale thick carbonate reservoirs is proposed. By combining the geological characteristics and dynamic performance of each well, vertical stacking pattern of the reservoir are classified, and also good insights into the lateral distribution of typical stacking patterns are also gained. The stacking pattern distributions are further projected onto the waterflooding well pattern, followed by rapid evaluation of production and injection rate of every block. Based on the simulation results for typical stacking pattern blocks, type curves of water flooding on different stacking pattern reservoirs are workout. Then the waterflooding performance for the whole carbonate reservoir is step-by-step quickly predicted at a constant liquid rate so as to keep the reservoir injection-production balance with voidage replacement ratio 1. Finally, a large-scale thick porous carbonate reservoir in the Middle East is taken as an example to show the workflow of the proposed method. The accuracy is further validated by comparing the predicted results from numerical simulation, indicating that the proposed method can save a lot of calculation time while ensuring the accuracy of performance forecast.

A oilfield is one of the first overseas oilfields in daqing oilfield’s going-out strategy. There is only a few years from the end of the development period. It is now in the middle and late stage of development. In the past two years, the water cut has increased greatly, the decline has accelerated, and the development cost has increased year by year. So it is urgent to study the limit value of production and water cut. At present, the calculation method of limit value is not suitable for the overseas oil field where the production needs to be divided. Therefore, this paper uses the break-even principle, combines the reservoir engineering theory knowledge and the overseas oilfield development contract, establishes the suitable overseas oilfield production and water cut calculation model. This model is used to calculate the limit value of A oilfield, and the result shows that the limit value of production and water cut of overseas oilfield has a great relationship with the contract proportion and oil price. Under the same oil price, the higher the proportion is, the lower the production limit is and the higher the water cut limit is. Under the same contract proportion, the higher the oil price is, the lower the production limit is and the higher the water cut limit is. In this paper, for the first time, a calculating model is established which can be used to calculate the limit value of production and water cut in overseas oilfields.

Abstract The giant H oil field was discovered in 1976 and put into development in 2008. The Mishrif reservoir has half of the geological reserves, and the current development challenges are greater. First, the sedimentary evolution is very complicated (inner ramp, lagoon, shallow sea, et al), the existing facies model is generally derived from rock type interpolation with kriging algorithm, and does not reflect sedimentary understanding, and is quite different from the actual situation displayed by seismic data. Furthermore, the variogram of rock types is also difficult to be accurate, resulting in poor fitting of reservoir simulation. Second, the seismic data quality is generally low, and its correlation with rock types is worse. If it is directly used to constrain rock type interpolation, the accuracy is generally unsatisfactory. In order to solve these problems, this study first comprehensively studied the core, thin slices, scanning electron microscopy, X-ray diffraction, electron probe and other data for sequence stratigraphy and sedimentary research. Secondly, based on the single well facies interpretation, combined with the inversion data, the dimension, spatial relationship and variogram of each depositional element were studied. Thirdly, the facies model was built using the Sequential Indicator Simulation (SIS) algorithm, and was manually modified zone by zone according to the sequence stratigraphy and sedimentary understanding. Finally, the relationship between depositional elements and rock types was studied, and the probability bodies of different depositional elements with different rock types were obtained. Based on this, the SIS algorithm was used to simulate rock types. Then this could be further used as a constraint to build petrophysical models. The results showed that the correlation between the depositional elements and the rock type was obviously better than the inversion wave impedance. The artificially modified facies model could better reflect sedimentary appearance, and various static and dynamic data. The rock type model obtained under the constraint of the facies model also bypassed the problem that the seismic data quality was not good enough for direct rock type interpolation. It was verified that with the new modeling workflow, the preliminary numerical simulation fitting rate reach over 80%. The facies model was then verified with water flooding test in H oil field and had good results. This workflow could provide a good reference for similar oilfields in the Middle East.

Heterogeneity of permeability is an important factor affecting the production of a carbonate reservoir. How to correctly characterize the heterogeneity of permeability has become a key issue for carbonate reservoir development. In this study, the reservoirs were categorized into four superimposed modes based on the actual logging data from a super-giant heterogeneous carbonate reservoir in the Middle East. A modified permeability formula in terms of the variogram method was presented to reflect the heterogeneity of the reservoirs. Furthermore, the models of oil production and water cut were established and the analytical solutions were obtained. The calculation results show that the present model can predict the productivity of wells with different heterogeneous layers more accurately and rapidly. The larger the varigoram value, the stronger the heterogeneity of the reservoirs, and the faster the decline of production owing to a quicker reduction of formation pressure. With the increase in variogram value, the relative permeability of the oil phase is smaller and the water phase larger, and the water cut becomes larger. This study has provided a quick and reasonable prediction model for heterogeneous reservoir.

Abstract For the same reservoir geological model, different simulation models could be obtained through history match calibration by different engineers. In other words, there are certain uncertainties within the calibrated simulation models. So how to reduce the uncertainty during history matching is still a problem. This paper presents how to quantify the waterflooding uncertainty and reasonably forecast waterflooding performance through reservoir simulation for a large multi-layered sandstone reservoir in Middle East. Based on the results of detailed geological characterization, dynamic description and parameter uncertainty analysis, three fine geological models are built, which stand for upside model, expected model and downside model. Then parameter sensitivity on waterflooding performance is conducted based on sector model simulation, and waterflooding development strategies are also optimized. The results are firstly applied for the three full field model calibration by reservoir history matching. After that the calibration models are used for waterflooding performance forecast and the performance uncertainty are also quantified. Take a large multi-layered sandstone reservoir in Middle East as an example. The MU reservoir is still under primary depletion with only 5% recovery currently, and waterflooding is urgent. Firstly, sector models are used for parameter sensitivity analysis and development strategy optimization. Then based on parameter sensitivity analysis results, the three full-field model are all calibrated with good history match. And different model calibration need different parameter adjustment, such as downside model has stronger aquifer support than that of upside model and expected model because of the poorer connectivity. So different models show different characteristics, such as most of west-south flank of MU reservoir are flooded for Downside model, while only some local area and some zones are water flooded for Expected and Upside model. Then waterflooding performance of different development plans are forecasted and compared based on the optimum development strategies and calibrated models. Furthermore, the performance uncertainty are quantified based on the three models. This paper offers a methodology and a case study of reservoir simulation history matching in order to reduce uncertainty and better waterflooding performance forecast for a large sandstone reservoir in Middle East. Comparison of the three models can help to better understand the reservoir. And the results are valuable for the following development options decision making. It also provides a reference for performance forecast and uncertainty analysis of similar reservoirs.

Abstract The inter-zone and intra-zone heterogeneity are the key issues for multi-layered sandstone reservoirs. While usually lots of equal probability fine geological models which match all constrained data can be built, and how to select the representative models for reservoir simulation is a problem. This paper presents how to compare different geological models and select representative models in detail for a multi-layered sandstone reservoir in Middle East. Through detailed geological characterization and dynamic description, different equal-probability geological models are built. And through geological check and analysis on each model, a preliminary comparison and understanding of each model are conducted, including gridding method comparison, vertical and lateral connectivity comparison etc. Then based on streamline numerical simulation, performance of each zone, each well for each model are compared in detail. Most performance are as we expected, but some are outliers. Through detailed analysis, the fundamental reasons for performance difference and major factors impacting on reservoir performance are determined. Finally, three models are selected for next reservoir simulation. Take K reservoir in Middle East for example, it is a large multi-layered sandstone reservoir of deltaic environment. K is influenced by fluvial, tide and wave, which results in great variations of sand bodies’ distribution, reservoir quality and connectivity. Nine equal-probability geocellular models of K reservoir are built, which use three different lateral connectivity patterns with three vertical gridding approaches representing different vertical connectivity during modelling. Model expected performance are firstly determined based on geological analysis of each model. Then, based on streamline simulation, performance comparison including water cut variation, recovery, etc. are conducted to all models for the zone level, member level and model level. Three models are finally selected which represent Upside model with good lateral and vertical connectivity, Expected model with medium connectivity and Downside model with poor connectivity respectively. These models can be used for reservoir development strategy and risk management study. This paper offers a case study of geological model comparison and selection mainly based on streamline simulation for a multi-layered sandstone reservoir. It ensures the selected models have reservoir heterogeneity correctly characterized, and the selected models are then used for the next development strategy and risk management study. It also provides a methodology and reference case for engineers to study on other similar reservoirs.