Callovian-Oxfordian sedimentary microfacies in the middle of Block B on the right bank of the Amu Darya Basin,Turkmenistan

The right bank of the Amu Darya Basin enjoys abundant natural gas resources,on which the Callovian-Oxfordian strata in the middle of Block B serve as the major horizons for natural gas production.However,the characteristics and distribution patterns of the sedimentary microfacies in these strata are yet to be further explored.Based on the analysis of data on drilling,logging,cores,and thin sections from 29 typical wells,as well as the regional sedimentary background,this study inferred that the middle of Block B evolved from the Callovian ramp platform into the Oxfordian rimmed platform.Moreover,this study determined that the inner-ramp intertidal-subtidal shallow-water subfacies mainly developed during the Callovian and transitioned into the shallow shelf subfacies during the Oxfordian.This study identified eight sedimentary microfacies,namely reef knoll,reef-shoal complex,bioclastic shoal,psammitic shoal,bioherm,lime mud mound,intershoal(intermound),and static-water mud.Based on research into the high-precision sequence-sedimentary microfacies framework,this study built a geological model for the development of sedimentary microfacies in the study area.According to this geological model,the sedimentary microfacies in the study area are characterized by vertical alternation of reef-shoal complex,bioclastic(psammitic)shoal,bioherm,and intershoal microfacies.Moreover,they show the development of reef knoll,reef-shoal complex,bioclastic(psammitic)shoal,and bioherm(or lime mud mound)laterally from west to east,with the physical properties of the reservoirs deteriorating from west to east accordingly.The microfacies of reef-shoal complex and the bioclastic(psammitic)shoal predominate in the study area,and their deposition and development are controlled by sequence boundaries and are also affected by paleo-landforms.The Oxfordian reef-shoal complexes were largely inherited from the Callovian uplifts and show lateral seaward progradation.

Correlation analysis between the Aral Sea shrinkage and the Amu Darya River

The shrinkage of the Aral Sea,which is closely related to the Amu Darya River,strongly affects the sustainability of the local natural ecosystem,agricultural production,and human well-being.In this study,we used the Bayesian Estimator of Abrupt change,Seasonal change,and Trend(BEAST)model to detect the historical change points in the variation of the Aral Sea and the Amu Darya River and analyse the causes of the Aral Sea shrinkage during the 1950–2016 period.Further,we applied multifractal detrend cross-correlation analysis(MF-DCCA)and quantitative analysis to investigate the responses of the Aral Sea to the runoff in the Amu Darya River,which is the main source of recharge to the Aral Sea.Our results showed that two significant trend change points in the water volume change of the Aral Sea occurred,in 1961 and 1974.Before 1961,the water volume in the Aral Sea was stable,after which it began to shrink,with a shrinkage rate fluctuating around 15.21 km3/a.After 1974,the water volume of the Aral Sea decreased substantially at a rate of up to 48.97 km3/a,which was the highest value recorded in this study.In addition,although the response of the Aral Sea's water volume to its recharge runoff demonstrated a complex non-linear relationship,the replenishment of the Aral Sea by the runoff in the lower reaches of the Amu Darya River was identified as the dominant factor affecting the Aral Sea shrinkage.Based on the scenario analyses,we concluded that it is possible to slow down the retreat of the Aral Sea and restore its ecosystem by increasing the efficiency of agricultural water use,decreasing agricultural water use in the middle and lower reaches,reducing ineffective evaporation from reservoirs and wetlands,and increasing the water coming from the lower reaches of the Amu Darya River to the 1961–1973 level.These measures would maintain and stabilise the water area and water volume of the Aral Sea in a state of ecological restoration.Therefore,this study focuses on how human consumption of recharge runoff affects the Aral Sea and provides scientific perspective on its ecological conservation and sustainable development.

Multi-resolution graph-based clustering analysis for lithofacies identifi cation from well log data: Case study of intraplatform bank gas fi elds, Amu Darya Basin

In this study, we used the multi-resolution graph-based clustering （MRGC） method for determining the electrofacies （EF） and lithofacies （LF） from well log data obtained from the intraplatform bank gas fields located in the Amu Darya Basin. The MRGC could automatically determine the optimal number of clusters without prior knowledge about the structure or cluster numbers of the analyzed data set and allowed the users to control the level of detail actually needed to define the EF. Based on the LF identification and successful EF calibration using core data, an MRGC EF partition model including five clusters and a quantitative LF interpretation chart were constructed. The EF clusters 1 to 5 were interpreted as lagoon, anhydrite flat, interbank, low-energy bank, and high-energy bank, and the coincidence rate in the cored interval could reach 85%. We concluded that the MRGC could be accurately applied to predict the LF in non-cored but logged wells. Therefore, continuous EF clusters were partitioned and corresponding LF were characteristics ＆different LF were analyzed interpreted, and the distribution and petrophysical in the framework of sequence stratigraphy.

A graphical model for haloanhydrite components and P-wave velocity:A case study of haloanhydrites in Amu Darya Basin

Wave velocities in haloanhydrites are difficult to determine and significantly depend on the mineralogy. We used petrophysical parameters to study the wave velocity in haloanhydrites in the Amur Darya Basin and constructed a template of the relation between haloanhydrite mineralogy （anhydrite, salt, mudstone, and pore water） and wave velocities. We used the relation between the P-wave rnoduli ratio and porosity as constraint and constructed a graphical model （petrophysical template） for the relation between wave velocity, mineral content and porosity. We tested the graphical model using rock core and well logging data.

Investigation of crop evapotranspiration and irrigation water requirement in the lower Amu Darya River Basin, Central Asia

High water consumption and inefficient irrigation management in the agriculture sector of the middle and lower reaches of the Amu Darya River Basin(ADRB)have significantly influenced the gradual shrinking of the Aral Sea and its ecosystem.In this study,we investigated the crop water consumption in the growing seasons and the irrigation water requirement for different crop types in the lower ADRB during 2004–2017.We applied the FAO Penman–Monteith method to estimate reference evapotranspiration(ET0)based on daily climatic data collected from four meteorological stations.Crop evapotranspiration(ETc)of specific crop types was calculated by the crop coefficient.Then,we analyzed the net irrigation requirement(NIR)based on the effective precipitation with crop water requirements.The results indicated that the lowest monthly ET0 values in the lower ADRB were found in December(18.2 mm)and January(16.0 mm),and the highest monthly ET0 values were found in June and July,with similar values of 211.6 mm.The annual ETc reached to 887.2,1002.1,and 492.0 mm for cotton,rice,and wheat,respectively.The average regional NIR ranged from 514.9 to 715.0 mm in the 10 Irrigation System Management Organizations(UISs)in the study area,while the total required irrigation volume for the whole region ranged from 4.2×109 to 11.6×109 m3 during 2004–2017.The percentages of NIR in SIW(surface irrigation water)ranged from 46.4%to 65.2%during the study period,with the exceptions of the drought years of 2008 and 2011,in which there was a significantly less runoff in the Amu Darya River.This study provides an overview for local water authorities to achieve optimal regional water allocation in the study area.

August–September Runoff Variation in the Kara Darya River Determined from Juniper(Juniperus turkestanica) Tree Rings in the Pamirs-Alai Mountains, Kyrgyzstan, Back to 1411 CE

A 606 year runoff reconstruction of the Kara Darya River was developed, based on the tree-ring width chronology of Turkestan juniper(Juniperus turkestanica) from the Pamir-Alai Mountains of Kyrgyzstan. Preliminary comparison between the snow cover variation and these climate/runoff reconstructions found that Central Asian snow cover may have strong associations with large-scale ocean-atmosphere-land circulations. The runoff reconstruction demonstrated that instrumental runoff was not representative of runoff over the past 606 years. The drought of the 1960 s-1990 s resulted in low runoff levels during the past 50 years;however, this probably does not represent a worst-case scenario for the Kara Darya because the runoff reconstruction showed additional extremely low runoff prior to the 20 th century. The reconstruction will provide a long-term perspective on runoff variation in the Kara Darya River basin, aid sustainable water resource management and be useful in guiding expectations of future variations and water resource planning.

Characteristics of an Upper Jurassic Carbonate Ramp in the Northern Amu-Darya Basin

Overemphasizing the value of reefs in oil and gas exploration, reef-oriented geologists explain all carbonate platform deposits using the Wilson model. In their eyes, rimmed shelves are more valuable than carbonate ramps. However, organic banks are excellent reservoirs generated by carbonate ramps in the study area, as verified beyond doubt through petroleum exploration, such as this thesis, which investigates the genesis, types, and distribution of carbonate deposition in the north zone of the Amu-Darya Basin. Monoclinal palaeogeomorphology and rudists suggest shallow environments. Given that oolite shoals and rudist patch reefs were observed in the study area, the depositional system is interpreted to be a carbonate ramp. The Callovian-Oxfordian stage consists of nine lithofacies: oolitic limestone, skeletal limestone, micritic limestone, bioturbated limestone, and crystalline limestone, which are grouped into three facies associations presenting outer ramp, mid-ramp, and inner ramp facies associations. Five depositional sequences can be distinguished in the Callovian-Oxfordian stage. Each third-order depositional sequence is composed of transgressive systems tracts (TST) and highstand systems tracts (HST). The TST consists of mudstones with a higher response to natural gamma rays, whereas the HST contains various types of grainstone, with subordinate dolostone. The vertical and lateral distributions of sedimentary facies, and their interpreted depositional environments, revealed a ramp exhibiting a gradual southeast-northwestward environmental change from outer ramp, mid ramp, and inner ramp carbonate facies.

Seismic geomorphology and stratigraphic trap analyses of the Lower Cretaceous siliciclastic reservoir in the Kopeh Dagh-Amu Darya Basin

Lower Cretaceous Shurijeh–Shatlyk Formations host some of the main reservoirs in the Kopeh Dagh-Amu Darya Basin.Exploration in this area so far has focused on the development of structural traps, but recognition of stratigraphic traps in this area is of increasing importance. Integration of 3D seismic data with borehole data from thirteen wells and five outcrop sections was used to identify potential reservoir intervals and survey the hydrocarbon trap types in the East Kopeh Dagh Foldbelt(NE Iran). Analyses of horizontal slices indicated that the lower Shurijeh was deposited in a braided fluvial system.Generally, three types of channel were identified in the lower Shurijeh Formation: type 1, which is low-sinuosity channels interpreted to be filled with non-reservoir fine-grained facies;type 2, which is a moderately sinuous sand-filled channel with good prospectively;and type 3, which is narrow, high sinuosity channel filled with fine-grained sediments. Results indicate that upper Shurijeh–Shatlyk Formations were deposited in fluvial to delta and shallow marine environments. The identified delta forms the second reservoir zone in the Khangiran Field. Study of the stratigraphic aspects of the Shurijeh succession indicates that both lower and upper Shurijeh reservoirs are stratigraphic reservoir traps that improved during folding.

Impact of aridization on soil cover transformation of the Aral Sea and the modern Syr-Darya Delta

The effects of human activities on the soil cover transformation in the eastern part of Kazakhstan were investigated during the period of 1956-2008.The results of the research for different soil types in Priaralye indicated that there was 643.3×103 hm2 solonchaks,accounting for 38.5 % of the total area（1670.5×10^3 hm^2） in 2008.Vast areas are occupied with dried lakeshore soil（311.1× 10^3 hm^2）,sandy soils（147.6×10^3 hm^2） and grey-brown desert soils and solonetzes（146.7×10^3 hm^2）.In 2001 the area of solonchak was 755×103 hm2 and decreased to 643.3×10^3 hm^2 in 2008,which due to the shrinkage of the Aral Sea,the areas of marsh and lakeshore solonchaks decreased with the increase of dried bottom of the Aral Sea.The level of soil cover transformation in the modern delta of the Syr-Darya River can be seen from the comparison of the results obtained from the different years in the study area.The area of solonchaks increased by 10×10^3 hm^2 and the area of alluvial-meadow salinizied soils increased by 17.9×10^3 hm^2 during the period of 1956-1969.It means that many non-salinizied soils were transformed into salinizied ones.Striking changes occurred in the structure of soil cover as a result of aridization.So,the researches in1969 significantly determined the areas of hydromorphic soils subjected to desertification（it was not fixed on the map before 1956）.Later,these soils were transformed into takyr-like soils.The area of takyr-like soils increased almost by 3 times for 34 years（from 1956 to 1990）.The long-term soil researches on soil cover transformation in Priaralye have shown that the tendencies of negative processes（salinization and deflation） are being kept and lead to further soil and eco-environment degradation in the region.

阿姆河右岸中-下侏罗统烃源岩地球化学特征及其沉积环境研究

阿姆河盆地是中亚地区天然气资源最丰富的盆地。阿姆河右岸区域的主力烃源岩存在于中-下侏罗统的煤系地层中,但烃源岩的地球化学特征、有机质来源及沉积环境还需进一步明确。本文以阿姆河盆地右岸地区侏罗系烃源岩为对象,在利用烃源岩样品开展系统的地球化学测试的基础上,对样品有机碳、镜质体反射率、饱和烃与芳烃气相色谱及有机碳同位素等数据进行了分析。结果表明:1)阿姆河右岸中-下侏罗统烃源岩的有机质丰度及生烃潜力较高,有机质类型以Ⅱ_(1)与Ⅱ_(2)型为主,存在少量Ⅲ型干酪根,烃源岩整体处于成熟—高成熟阶段;烃源岩以生油为主,兼生气。2)阿姆河右岸中-下侏罗统烃源岩大部分沉积于高盐度的强还原环境,少数沉积于低盐度氧化环境中。3)阿姆河右岸中-下侏罗统烃源岩中有机质母质的来源主要为低等浮游生物,部分有机质来源于高等植物。

巨厚膏盐岩形变机制解析及其对油气成藏的影响——以阿姆河右岸东部阿盖雷地区侏罗系为例

阿姆河右岸侏罗系钦莫利阶发育巨厚膏盐岩,其对油气富集成藏具有重要影响。综合利用钻井岩心测试资料和地震资料,通过剖面地质形态分析与地震分频属性刻画,对阿姆河右岸东部阿盖雷地区侏罗系与膏岩层相关的典型构造样式进行了识别,并解析了其形变机制,恢复了关键成藏期的古构造,探讨了不同时期构造运动对油气运聚成藏的控制作用。研究结果表明:①阿盖雷地区侏罗系上盐层上部及上覆地层发育滑脱褶皱,下部发育少量大型盐枕构造,中石膏—下盐层—下石膏层整体变形程度较低,下盐层内发育3种形态小型盐枕构造及盐缩颈,盐枕构造间可识别典型礁/丘滩体。②研究区构造挤压应力和重力滑脱作用是形成膏盐岩形变的主要动力,考虑“2期主要构造运动、先存地貌/构造、多层差异化变形塑性地层、纵横向复合叠加变形”4项关键因素建立了多层叠覆型复杂构造变形模式。③采用基于盐层流动增厚量回填的厚度图法恢复了研究区上盐层沉积前、早白垩世末生烃高峰期的古构造,综合生排烃史、构造发育史、气井产量,明确了基于膏盐岩形变恢复的古构造是天然气富集高产的重要因素,具有“天然气持续充注、多期动态成藏”的演化特征,古、今构造继承性发育区为天然气富集的最有利区。

碳酸盐岩构造裂缝特征与形成期次分析:以阿姆河盆地右岸东部为例

碳酸盐岩裂缝对石油和天然气勘探开发具有重要意义,但碳酸盐岩构造裂缝特征描述、形成和影响因素一直是油气储层研究的重点。综合利用岩心、测井解释和分析测试等资料,对阿姆河盆地右岸东部地区侏罗系卡洛夫-牛津阶碳酸盐岩储层内构造裂缝特征进行研究,划分构造裂缝类型及发育期次,明确影响构造裂缝发育的影响因素,分析多期次裂缝对天然气聚集的影响。结果表明:(1)构造裂缝是阿姆河盆地右岸东部侏罗系卡洛夫-牛津阶储层中发育的主要裂缝类型,按照产状分为水平缝、低角度缝、高角度缝和垂直缝;卡洛夫-牛津阶储层构造裂缝总体上走向以NW-SE向为主,但不同裂缝的走向差异性较大,反映了裂缝具有多期发育的特点,不同类型的构造裂缝在产状、密度和规模存在差异,中下侏罗统的XVa1层中最发育,平均裂缝密度为1.48条/m;构造裂缝的规模普遍较大,在上侏罗统的XVhp层裂缝宽度和裂缝高度最大,平均裂缝宽度约0.08 mm、平均裂缝高度67.1 cm,构造裂缝的倾角多介于40°~70°;(2)阿姆河盆地右岸东部侏罗系卡洛夫-牛津阶储层构造裂缝的发育程度存在较大的差异,这是由于裂缝的发育不仅受到岩性的控制,还受到多期构造运动的影响,亮晶砂屑灰岩和生物礁灰岩为构造裂缝发育的优势岩性;新近纪的挤压作用强烈,在侏罗系卡洛夫-牛津阶岩心中形成相互交错的网状裂缝,为裂缝期次划分提供有利证据;(3)阿姆河盆地右岸东部侏罗系卡洛夫-牛津阶中构造裂缝形成于燕山晚期到喜山中期,其中晚期裂缝的形成不仅改善了储层物性,也促进天然气聚集和成藏。

射线域弹性阻抗反演在阿姆河右岸碳酸盐岩气藏储层预测中的应用

阿姆河右岸阿盖雷气田中上侏罗统卡洛夫—牛津阶碳酸盐岩储层勘探难度大、地震反射能量弱、地震资料信噪比低。以储层特征及岩石物理分析为基础,通过叠前道集优化处理、井-震联合低频阻抗建模以及叠前射线域弹性阻抗反演方法,对该地区含气储层进行了预测。研究结果表明:①阿盖雷气田中上侏罗统卡洛夫—牛津阶储层主要为台地前缘缓坡相碳酸盐岩,岩性主要为砂屑灰岩和生屑灰岩,储集空间以孔隙-裂缝型为主,具有低孔、低渗和非均质性强的特征;有效含气储层主要表现为低纵波阻抗、低剪切模量、低体积模量特征,剪切模量对含气储层的敏感程度最高。②通过预测剔除去噪,奇异值分解去噪和谱平衡能量补偿手段对叠前道集进行处理可以有效去除异常振幅等高频及随机噪音,提升有效信号强度并增强远偏移距AVO特征;井-震联合建模方法通过引入低频层速度解决因地震数据低频信息缺失而造成的反演多解性问题,提高了反演精度的同时有效表征了储层横向变化;叠前射线域弹性阻抗反演方法在研究区应用效果好,纵、横波阻抗反演体在纵、横向上均表现出较高的分辨能力,预测的含气储层厚度与测井解释的成果吻合度达85%以上,反演体显示气层的横向连续性较差,符合缓坡滩沉积特征。③研究区碳酸盐岩储层具有良好的勘探开发潜力,东部和西南部的未钻区域有多处明显的含气显示;上部Gap—XVhp段含气显示更好。

阿姆河盆地东北部碳酸盐岩区域性地层超压成因

由于碳酸盐岩沉积成岩作用与碎屑岩不同,碳酸盐岩地层超压具有高度非均质性,然而阿姆河盆地东北部地区碳酸盐岩地层却发育了大面积区域性超压现象。本文运用实测地层压力和钻井液密度计算压力的方法,刻画了研究区碳酸盐岩地层异常超压的空间分布特征及其与上覆膏盐岩地层压力的垂向叠置关系,运用碳酸盐岩物性、压汞分析和烃源岩生烃模拟及构造挤压增压模拟等方法,从纵向与横向对比超压与常压差异分布的角度,探讨了碳酸盐岩超压成因。研究表明:盐下碳酸盐岩发育常压与强超压,强超压区大面积连续发育,与局部构造和断裂无关。盐下致密碳酸盐岩形成封闭体系,虽然构造挤压作用发育了断层与裂缝,但是由于膏盐岩的塑性,未破坏盐下碳酸盐岩封闭体系,是超压区域性连续发育的前提;同时,强烈构造挤压对超压发育有重要贡献。由于膏盐岩的良好封闭性,使膏盐岩层与碳酸盐岩层之间优质烃源岩(TOC最高达6%)生成液态烃类向盐下碳酸盐岩排烃,也促进了超压发育;由于膏盐岩与碳酸盐岩之间发育的泥岩隔层,石膏矿物脱水作用不是碳酸盐岩超压的成因,并且,石膏成岩脱水作用对盐下碳酸盐岩开放体系作用微弱。研究成果对盐下异常超压的预测具有借鉴意义。

Carbon and Oxygen Isotope Stratigraphy of the Oxfordian Carbonate Rocks in Amu Darya Basin

Based on the detailed research on petrologic and geochemical characteristics of deposi- tion and diagenesis of Oxfordian carbonate rocks in Amu Darya Basin, Turkmenistan, carbon and oxygen isotopes were analyzed. The results show that the paleoenvironmental evolution reflected by the samples with well-preserved original carbon isotopes coincides with the carbon-isotope stratigraphic curve and is almost consistent with the global sea-level curve, the Mid-Oxfordian wide transgression, and the positive carbon-isotope excursion event. The Mid-Oxfordian continuing transgression not only laid the foundation for the development of the Oxfordian reef and shoal reservoirs in Amu Darya Basin but also provided an example for the Oxfordian global transgression and the resulting development of reefs and banks and high-speed organic carbon burial events. The response of oxygen isotopes in diagenetic environment showed that micrite limestones and granular limestones underwent weak diagenetic alteration, and the samples largely retained the original seawater features. Dolomitization and the precipitation of hydrothermal calcites filling solution vugs and fractures before hydrocarbon accumulation occurred in a closed diagenetic environment where the main controlling factor is the temperature, and the diagenetic fluids were from the deep hot brine. The chalkification of the lime- stones after hydrocarbon accumulation occurred in the oilfield water systems.

Baseline determination,pollution source and ecological risk of heavy metals in surface sediments of the Amu Darya Basin,Central Asia

Central Asia(CA)is one of the most fragile regions worldwide owing to arid climate and accumulated human activities,and is a global hotspot due to gradually deteriorating ecological environment.The Amu Darya Basin(ADB),as the most economically and demographically important region in CA,is of particular concern.To determine the concentration,source and pollution status of heavy metals(HMs)in surface sediments of the ADB,154samples were collected and analyzed for metals across the basin.Correlation and cluster analysis,and positive matrix factorization model were implemented to understand metals’association and apportion their possible sources.Cumulative frequency distribution and normalization methods were used to determine the geochemical baseline values(GBVs).Then,various pollution indices and ecological risk index were employed to characterize and evaluate the pollution levels and associated risks based on the GBVs.Results indicated that the mean concentrations of HMs showed the following descending order in the surface sediments of ADB:Zn>Cr>Ni>Cu>Pb>Co>Cd.The spatial distribution maps showed that Cr,Ni,and Cu had relatively high enrichment in the irrigated agricultural area;high abundances of Zn,Pb,and Cd were mainly found in the urban areas.Four source factors were identified for these metals,namely natural sources,industrial discharge,agricultural activities,and mixed source of traffic and mining activities,accounting for 33.5%,11.4%,34.2%,and 20.9%of the total contribution,respectively.The GBVs of Cd,Zn,Pb,Cu,Ni,Cr,and Co in the ADB were 0.27,58.9,14.6,20.3,25.8,53.4,and 9.80 mg/kg,respectively,which were similar to the regional background values obtained from lake sediments in the bottom.In general,the assessment results revealed that surface sediments of the ADB were moderately polluted and low ecological risk by HMs.

阿姆河右岸区域构造大剖面解析及成因探讨

阿姆河盆地右岸区块地理位置位于土库曼斯坦的阿姆河流域北侧至土库曼斯坦—乌兹别克斯坦国境线南侧之间,西南紧邻吉萨尔山脉,是中石油重要的海外油气勘探开发基地。开展其构造特征解析和成因机制探讨,对研究含盐盆地分层构造变形特征和促进能源勘探开发均具有重要意义。以构造建模和构造复原理论为指导,精细解释过阿姆河右岸区块的东西向地震大剖面,分析其地质结构特征和形成演化过程。结果表明:阿姆河右岸区块纵向上发育前二叠系基底和二叠系—第四系沉积盖层。以上侏罗统基末利—提塘阶膏盐岩为界,盐上和盐下构造形态具分层变形特征;盐上多发育陡窄的滑脱褶皱,断裂以倾向NW的小断距正断层和走滑断层为主;盐下多发育宽缓的冲断褶皱,断裂以倾向SE的大断距逆断层为主。受基底构造楔楔入影响,研究区自西向东构造抬升和挤压幅度逐渐增大。根据平衡剖面复原并结合区域地质背景,将研究区构造演化划分为前二叠纪基底形成期、二叠—三叠纪弧后裂谷期、侏罗—古近纪稳定沉积期和新近纪以来挤压抬升期共4期构造演化阶段。新生代多方向构造叠加影响、基底构造楔活动和膏盐岩对分层构造变形的调节作用是阿姆河盆地右岸地区纵向分层、横向分带构造特征的主要控制因素。

碳酸盐岩裂缝型储集层全直径岩心水侵规律实验

阿姆河右岸海相碳酸盐岩气藏断层及裂缝发育,局部水体能量活跃,开发效果受水侵影响显著。通过高温高压复杂缝洞储集层全直径岩心驱替实验,分析裂缝渗透率、裂缝贯穿程度和水体倍数对气藏水侵的影响,结合水气比动态变化特征,研究不同裂缝岩心的水侵规律。结果表明,裂缝贯穿程度越高,裂缝渗透率越大,水体倍数越高,则对应水侵模式中水气比曲线的斜率越大,说明水侵、水窜越严重,而裂缝未贯穿区域对暴性水淹能起到较好的抑制作用。在上述认识基础上,通过水侵模式分析诊断曲线,进一步分析了不同水侵模式的特征,优化了研究区气藏水侵诊断的指数图版。

中亚阿姆河右岸东部地区侏罗系盐下碳酸盐岩储层特征及预测新方法

以岩心、薄片及测井资料为基础,分析了中亚阿姆河右岸东部地区侏罗系牛津阶储层的岩性、储集空间及物性特征,利用三维地震数据,通过正演地震模拟、波形聚类技术、分频RGB融合技术以及集成学习等方法,对储层分布及厚度进行了半定量预测。研究结果表明:①阿姆河右岸东部地区侏罗系牛津阶储层岩性主要为生屑灰岩、颗粒灰岩及泥晶灰岩,为裂缝-孔洞型储层,储集空间以生物格架孔、粒内孔和裂缝为主,裂缝为后期溶蚀流体提供了通道;储层平均厚度为41.6 m,平均孔隙度为4.65%。②研究区储层多发育于XVhp层,根据其在XVhp层的分布位置可分为顶部型、底部型和两期型,顶部型储层主要分布于研究区中部及东部,底部型储层主要集中于西部,而两期型储层大量发育于西北部;研究区西部和东北部储层发育较好,厚度为45~75 m,多沿断裂发育带分布,东南部储层发育较差,厚度小于30 m,距离断层更远。③利用集成学习方法计算研究区储层厚度时,采用异质集成方法中的Stacking方法进行模型运算,以基于箱线图的离群值剔除方法剔除极端数据,以交叉验证法评估模型的预测性能,得到的储层厚度与11口实钻井储层厚度的变化趋势相符,相关系数为0.74。

阿姆河盆地别什肯特坳陷及邻区中下侏罗统烃源岩地球化学特征与勘探意义

阿姆河盆地别什肯特坳陷及邻区中下侏罗统发育一套潜在烃源岩,此烃源岩也是一套潜在的含油气系统,但是目前研究仍然薄弱。为此,通过钻井岩心和岩屑有机地球化学分析及盆地模拟方法,研究了别什肯特坳陷及邻区中下侏罗统烃源岩的有机质丰度、类型与成熟度等地球化学特征及烃源岩的形成环境,并明确了油气勘探的方向。研究结果表明:①中下侏罗统海陆过渡相泥岩段烃源岩有机质丰度介于0.50%~3.53%(平均值为1.27%),有机质类型为偏腐殖混合型,有机质热演化程度为介于0.7%~1.1%,为有效烃源岩;②泥岩段上部的浅海相泥质石灰岩段有机质丰度低,为非烃源岩;③泥岩烃源岩可溶有机物以低碳数正构烷烃为主,呈典型单峰,C27甾烷含量高于C29甾烷,三环萜烷和四环萜烷含量高,但是饱/芳比低,孕甾烷含量高,芳烃硫芴含量高,因此,有机质可能来自浅水的宏观底栖藻类,形成于潟湖环境。结论认为,别什肯特坳陷中下侏罗统烃源岩在早白垩世晚期已成熟,以生气为主,生油为辅,现今仍处在生烃高峰阶段,与构造圈闭形成时期配置好,具备较大的成藏潜力;致密砂岩气是该套含油气系统的重要勘探方向。