Effect of CO_(2)flooding in an oil reservoir with strong bottom-water drive in the Tahe Oilfield,Tarim Basin,Northwest China

The dissolution and diffusion of CO_(2)in oil and water and its displacement mechanism were investigated by laboratory experiment and numerical simulation for Block 9 in the Tahe oilfield,a sandstone oil reservoir with strong bottom-water drive in Tarim Basin,Northwest China.Such parameters were analyzed as solubility ratio of CO_(2)in oil,gas and water,interfacial tension,in-situ oil viscosity distribution,remaining oil saturation distribution,and oil compositions.The results show that CO_(2)flooding could control water coning and increase oil production.In the early stage of the injection process,CO_(2)expanded vertically due to gravity differentiation,and extended laterally under the action of strong bottom water in the intermediate and late stages.The CO_(2)got enriched and extended at the oil-water interface,forming a high interfacial tension zone,which inhibited the coning of bottom water to some extent.A miscible region with low interfacial tension formed at the gas injection front,which reduced the in-situ oil viscosity by about 50%.The numerical simulation results show that enhanced oil recovery(EOR)is estimated at 5.72%and the oil exchange ratio of CO_(2)is 0.17 t/t.

Quantitative characterization of deep fault-karst carbonate reservoirs: A case study of the Yuejin block in the Tahe oilfield

The Ordovician reservoirs in the Tahe oilfield are dominated by fractured-vuggy carbonate reservoirs, of which fault-karst reservoirs are a hot topic in recent years. Fault-karst reservoirs feature high production, large burial depth, and strong heterogeneity under the control of faulting and karstification. Based on geological, logging, and seismic data, this study classified the Ordovician fault-karst reservoirs in the Yuejin block of the Tahe oilfield into three types, namely karst-cave, dissolved-vug, and fractured types, and established the integrated identification criteria of the three types of reservoirs. This study characterized karst caves, dissolved vugs, and multi-scale faults through seismic wave impedance inversion and frequency-domain detection of multi-scale faults. 3D geological models of different types of reservoirs were built using the combined deterministic and stochastic methods and characterized the spatial distribution of multi-scale faults, karst caves, dissolved vugs, and physical property parameters of reservoir. This study established the method for the geological modeling of fault-karst reservoirs, achieved the quantitative characterization and revealed the heterogeneity of fault-karst reservoirs. The karst-cave and dissolved-vug types are high in porosity and act as reservoirs, while the fractured type is high in permeability and act as flow pathway. This study lays the foundation for the development index prediction, well emplacement, and efficient development of the fault-karst carbonate reservoirs.

Research progress and potential of new enhanced oil recovery methods in oilfield development

This paper reviews the basic research means for oilfield development and also the researches and tests of enhanced oil recovery(EOR)methods for mature oilfields and continental shale oil development,analyzes the problems of EOR methods,and proposes the relevant research prospects.The basic research means for oilfield development include in-situ acquisition of formation rock/fluid samples and non-destructive testing.The EOR methods for conventional and shale oil development are classified as improved water flooding(e.g.nano-water flooding),chemical flooding(e.g.low-concentration middle-phase micro-emulsion flooding),gas flooding(e.g.micro/nano bubble flooding),thermal recovery(e.g.air injection thermal-aided miscible flooding),and multi-cluster uniform fracturing/water-free fracturing,which are discussed in this paper for their mechanisms,approaches,and key technique researches and field tests.These methods have been studied with remarkable progress,and some achieved ideal results in field tests.Nonetheless,some problems still exist,such as inadequate research on mechanisms,imperfect matching technologies,and incomplete industrial chains.It is proposed to further strengthen the basic researches and expand the field tests,thereby driving the formation,promotion and application of new technologies.

Performance Evaluation of the Halophilic Crude Oildegrading Bacterial Consortium XH-1 for Oilfield Wastewater Treatment

A total of 14 halophilic hydrocarbon-degrading strains were isolated from crude oil-contaminated sites,using petroleum as the sole carbon and energy source.Among these,four highly efficient strains were selected to create the mixed bacterial agent XH-1.These four strains were identified through 16S rRNA gene-based sequencing as belonging to Acinetobacter,Bacillus paramycoides,Rhodococcus sp.,and Enterobacter sp.,respectively.The optimal cultivation time for the mixed consortium XH-1 was found to be 48 h,and a nitrogen-phosphorus molar ratio of 10:1 was determined to be beneficial for crude oil degradation.XH-1 showed notable crude oil degradation even at a salinity of up to 30 g/L,with little inhibition observed at sulfide concentrations as high as 150 mg/L and initial oil concentrations of 500 mg/L.Gas chromatography analysis revealed that XH-1 was able to efficiently degrade C9–C29 n-alkanes.Moreover,a bio-contact oxidation reactor enhanced by XH-1 showed promising results in treating oilfield wastewater.These findings suggest that XH-1 can be applied for the treatment of oilfield wastewater.

Types of Karst-fractured and Porous Reservoirs in China's Carbonates and the Nature of the Tahe Oilfield in the Tarim Basin

Almost all the oil and gas reservoirs developed in marine sedimentary strata of China have undergone processes of multi-phase reservoir formation and later modification. The irregular reservoirs are classified into three types as the Naxi, Tahe and Renqiu ones, increasing successively in the development degree of karstificated pores and fissures and the connection degree of independent reservoirs. In these reservoirs, the unity in the fluid feature, pressure and oil-gas-water interface also increases successively from the Naxi to the Renqiu type. The main body of Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin is a network pool rather than a stratified, massive, stratigraphically-unconformed or weathering-crust one. The fluid nature of oil, gas and water, the interface positions and the pressures, as well as the dynamic conditions of fluids within the reservoirs during the production are all different from those in stratified or massive oil and gas reservoirs. Carbonates in the Akekule uplift and the Tahe Oilfield are assemblages of various types of reservoirs, which have an overall oil-bearing potential and obvious uneven distribution. Testing and producing tests are the major means to evaluate this type of reservoirs and acid fracturing improvement is a key link in petroleum exploration and development.

Burial Dissolution of Ordovician Granule Limestone in the Tahe Oilfield of the Tarim Basin,NW China,and Its Geological Significance

With a comprehensive study on the petrology, geology and geochemistry of some Ordovician granule limestone samples in the Tahe Oiifieid of the Tarim Basin, two stages of burial dissolution were put forward as an in-source dissolution and out-source dissolution based on macro-microcosmic petrology and geochemistry features. The main differences in the two stages are in the origin and moving pass of acid fluids. Geochemical evidence indicates that burial dissolution fluids might be ingredients of organic acids, CO2 and H2S associated with organic matter maturation and hydrocarbon decomposition, and the in-source fluid came from organic matter in the granule limestone itself, but the out-source was mainly from other argillaceous carbonate rocks far away. So, the forming of a burial dissolution reservoir resulted from both in-source and the out-source dissolutions. The granule limestone firstly formed unattached pinholes under in-source dissolution in situ, and afterwards suffered wider dissolution with out-source fluids moving along unconformities, seams, faults and associate fissures. The second stage was much more important, and the mineral composition in the stratum and heat convection of the fluid were also important in forming favorable reservoirs.

A Study of the Genesis of Karst-type Subtle Reservoir in Tahe Oilfield

The genesis of the Ordovician karst in the Tahe Oilfield is hypothesized on the basis of many analyses of the geo-chemical data and the sporopollen. Ordovician carbonate rocks experienced multistage karst reconstructions under the condition of low-temperature oxidation meteoric water on the surface or near-surface. The karst occurred mainly in the early Hercynian, which has undergone three stages of karst cycle and developed three sets of cave reservoirs under the influence of the tectonic uplift, and the upper of the cave was formed earlier. The evidence of karst was found in the Caledonian. On the above basis, the genetic prediction pattern of the Ordovician palaeokarst reservoir in this region was set up.

Quantitative assessment and significance of gas washing of oil in Block 9 of the Tahe Oilfield,Tarim Basin,NW China

Some Ordovician and Triassic oils in Block 9 are characterized by light oils,which have distinctly differentiated from heavy oils in other blocks in the Tahe Oilfield,Tarim Basin.Based on the whole oil gas chroma- tograms,this paper estimates the effect of oil migration and fractionation and the amount of depletion(Q)in terms of the n-alkanes depletion model.The results showed that the amount of depletion in the Ordovician reservoir is highest in the east of this block,e.g.the depletion is 97% in Well T904.The amount of Q gets lower to the west,e.g.the depletion is 53.4%in Well T115 and there is no sign of depletion in Well S69.It is suggested that the direction of gas washing is from the east to the west.The compositions and isotopic characteristics of associated gas in Ordovician oils indicated that the gas might be derived from Cambrian source rocks of the Caohu Depression which lies to the east of Block 9.In contrast,no obvious depletion of n-alkanes in Triassic oils was found,suggesting that the migration pathway of natural gas has been limited to the Ordovician karst fracture system formed in the Early Hercynian Orogeny.Different depletions of the Ordovician and Triassic oils can reveal fault activities in this region.

Reservoir characterization of the Odovician oil and gas pools in the Tahe Oilfield, Tarim Basin, Northwest China

About 88. 1% of the proven reserves in the Tahe Oilfield in the Tarim Basin of Northwest China are trapped in Ordovician carbonate reservoirs. These reservoirs are formed by unconnected and interconnected networks of karstic porosity forming a heterogeneous and complex reservoir system. Oil, water and gas characteristics vary significantly in different portions of the Ordovician reservoir. There is no uniform oil/water contact in the field, adding to its complexity.An acid fracture treatment is beneficial in 76% of the wells, stimulating nonproductive wells and enhancing production in other wells by fracturing into unconnected reservoirs and enhancing flow pathways with acid. Acid fracture treatments should be a standard procedure for developing this and similar oil fields.

Distribution of the Ordovician Fluid in the Tahe Oilfield and Dynamic Response of Cave System S48 to Exploitation

The Tahe Oilfield is a complex petroleum reservoir of Ordovician carbonate formation and made up of spatially overlapping fracture-cavity units. The oilfield is controlled by a cave system resulting from structure-karst cyclic sedimentation. Due to significant heterogeneity of the reservoir, the distribution of oil and water is complicated. Horizontally, a fresh water zone due to meteoric water can be found in the north part of the Akekule uplift. A marginal freshening zone caused by water released from mudstone compaction is found at the bottom of the southern slope. Located in a crossformational flow discharge zone caused by centripetal and the centrifugal flows, the main part of the Tahe Oilfield, featuring high salinity and concentrations of CI^- and K^＋＋Na^＋, is favorable for accumulation of hydrocarbon. Three types of formation water in the Tahe Ordovician reservoir are identified： （1） residual water at the bottom of the cave after oil and gas displacement, （2） residual water in fractures/pores around the cave after oil and gas displacement, and （3） interlayer water below reservoirs. The cave system is the main reservoir space, which consists of the main cave, branch caves and depressions between caves. Taking Cave System S48 in the Ordovician reservoir as an example, the paper analyzes the fluid distribution and exploitation performance in the cave system. Owing to evaporation of groundwater during cross-formational flow, the central part of the main cave, where oil layers are thick and there is a high degree of displacement, is characterized by high salinity and Br^- concentration. With high potential and a long stable production period, most wells in the central part of the main cave have a long water-free oil production period. Even after water breakthrough, the water content has a slow or stepwise increase and the hydrochemistral characteristics of the produced water in the central part of the main cave are uniform. From the center to the edge of the main cave, displacement and enrichment of oil/gas become weaker, residual water increases, and the salinity and concentration of Br^- decrease. At the edge of the main cave, although the wells have a high deliverability at the beginning with a short stable production period and water-free production period. After water breakthrough, the pressure and deliverability drop quickly, and the water content rises quickly. The hydrochemistral characteristics of the produced water are relatively uniform. Wells in the branch caves have a relatively low deliverability at the beginning, with a short stable production period. Water breakthrough appears quickly and then the pressure and deliverability drop quickly. The salinity and concentrations of CI^-and K^＋＋Na^＋ are usually fluctuant or descend slowly in the produced water. Wells in low areas of ancient karst have a low deliverability and a short stable production period. The yield drops quickly and the water content is high, while the characteristics of the produced water may vary significantly well to well. The salinity and concentrations of CI^-and K^＋＋Na^＋ in the produced water are usually fluctuant with a precipitous decline.

Migration,filling history and geochemical characteristics of Ordovician natural gases in the Tahe Oilfield,Tarim Basin,Northwest China

Ordovician natural gases in the Tahe Oilfield are composed predominantly of hydrocarbon gases dominated by methane with a significant amount of heavy hydrocarbon gas component. The non-hydrocarbon gases include N2, CO2 and minor H2S. The Ordovician natural gases are believed to have originated from the same source rocks, and are composite of gases differing in thermal maturity. Carbon dioxide was derived from thermal metamorphism of Ordovician carbonate rocks. The generation of natural gases involves multiple stages from mature normal oil and condensate-associated gas to thermally cracked gas at the maturity to over-maturity stages. In the main part of the Tahe Oilfield, the Ordovician natural gases appear to be filled in two major phases with a typical petroleum-associated gas from southeast to northwest and from east to west in the early stage; and a thermally cracked gas from east to west in the late stage. At the same time, the oil/gas filling boundary has been primarily established between the two stages.

Hydrocarbon Inclusion Characteristics in the Cambrian-Ordovician Carbonates of the TS2 Well:Implication for Deep Hydrocarbon Exploration in the Tahe Oilfield,Tarim Basin,Northwest China

Going deep has been the strategy for the sustainable development of the Tahe Oilfield.Following the TS1 well in block 1,which revealed excellent combinations of hydrocarbon generation,migration and accumulation in the deeper parts of the Tarim Basin,the TS2 well was drilled to learn more about the prospectivity in the deeper parts of the main blocks of the Tahe Oilfield.Seventeen core samples were collected to perform fluid inclusion studies,including petrography,fluorescence microspectrometry,and microthermometry.The results show that the deeper parts of the Tahe Oilfield have a good hydrocarbon potential.The Cambrian source rocks can supply sufficient oil for not only the Cambrian reservoirs,but also for the Lower Ordovician reservoirs.The CambrianOrdovician carbonates reservoirs experienced at least three oil charging events and one late gas charging event.Oil accumulations formed in the early stage of basin evolution were likely destroyed in the late stage with deep burial,tectonic movements,or invasion of hydrothermal fluids.Therefore,the deep hydrocarbon exploration of the Tahe Oilfield,even the whole Tarim Basin,should focus on gas accumulations,although oil accumulations,especially in Cambrian reservoirs,cannot be neglected.

Architecture characterization of Ordovician fault-controlled paleokarst carbonate reservoirs in Tuoputai,Tahe oilfield,Tarim Basin,NW China

Based on outcrop,core,logging,seismic and production data,and the formation of fault-controlled karst reservoirs,the types and characterization of Ordovician fault-controlled karst reservoir architectures in the Tuoputai area of the Tahe oilfield are studied.According to the concept of genetic geologic body,the fault-controlled karst reservoir is divided into architecture elements of four levels,the strike-slip fault impact zone is the level-1 architecture element,the fault-controlled karst reservoir the level-2 architecture element,the fracture-cave zone(which can be further subdivided into dissolution cave,dissolution pore and vug,and fracture zones)inside the fault-controlled karst reservoir the level-3 architecture element,and fillings inside caves is the level-4 architecture element(which can be further divided based on the filling degree and lithologic types of the fillings).Specific characterization techniques have been optimized according to the characteristics of various architecture elements.The zone impacted by strike-slip fault is characterized by seismic coherence and artificial interpretation.Under the constraint of zone impacted by strike-slip fault,fault likelihood(FL)property is used to characterize the outline of fault-controlled karst reservoir.Under the constraint of fault-controlled karst reservoir outline,the internal structures are divided based on seismic texture attribute.Finally,the cavern filling pattern is interpreted based on drilling and logging data.The fault-controlled karst reservoirs can be interpreted in 3-dimensional space by architecture element levels,and the characterization technology combining log and seismic data for fault-controlled karst reservoir has been worked out,which has complemented the development theory and technologies for this kind of reservoirs in the Tahe oilfield.

Origin, hydrocarbon accumulation and oil-gas enrichment of fault-karst carbonate reservoirs: A case study of Ordovician carbonate reservoirs in South Tahe area of Halahatang oilfield, Tarim Basin

Based on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir in Yueman block of South Tahe area, Halahatang oilfield, Tarim Basin, were studied systematically. And the regular pattern of hydrocarbon accumulation and enrichment was analyzed systematically based on development practice of the reservoirs. The results show that fault-karst carbonate reservoirs are distributed in the form of "body by body" discontinuously, heterogeneously and irregularly, which are controlled by the development of faults. Three formation models of fault-karst carbonate reservoirs, namely, the models controlled by the main deep-large fault, the secondary fault and the secondary internal fault, are built. The hydrocarbon accumulation and enrichment of fault-karst carbonate reservoirs is controlled by the spatiotemporal matching relation between hydrocarbon generation period and fault activity, and the size and segmentation of fault. The study results can effectively guide the well deployment and help the efficient development of fault-karst carbonate reservoirs of South Tahe area, Halahatang oilfield.

Development of Karst Formation in Area 4 of Tahe Oilfield

The main oil-bearing formation of Area 4 of Tahe oilfield is in Yingshan Group of Ordovician consisted of thick pure limestone. The types of the pore space contain the pore, fissure, cave as well as fracture formed by solution collapse. The primary porosity and tectonic fracture are of poor growth. Therefore, the formation growth is mainly controlled by hydraulic units of the palaeo-karst. There are three palaeo-hydraulic zones: vadose zone (including infiltration sub-zone and percolation sub-zone), phreatic zone and tranquil zone. They are identified by retrieving the palaeo-geographical karst environment. The pore space of the infiltration zone is mainly solution fissures, small solution cavities and solution pores. The growth and lateral connection of the formation are favorable. The reservoir/formation ratio is 0. 54. The pore space of the phreatic zone developed large size cavities and fractures related to cave collapse. The height of the cavity can reach 71m. The fractures by collapse have a influencing range of more than 100m, and its reservoir/formation ratio is 0. 51. But the lateral connection is unfavorable. The percolation subzone and the tranquil zone are of relatively poor growth with the reservoir/ formation ratio less than 0. 3.

塔里木盆地塔河油田塔深5井震旦系原油地球化学特征及地质意义

塔深5(TS5)井于2021年完钻,井深9 017 m,是目前亚洲第一深井,同时也是塔里木盆地台盆区第一口在8 780~8 840 m的上震旦统白云岩段获得油气突破的钻井,也是继轮探1井寒武系盐下突破后,超深层白云岩领域的又一重大发现。为了探究其油气成因,分别对TS5井震旦系凝析油和上部奥陶系重质油,及其邻区寒武系挥发油和奥陶系凝析油进行了有机地球化学特征对比。结果表明,TS5井震旦系凝析油和白云岩储层氯仿抽提物的正构烷烃系列均分布完整,指示了其生烃母质形成于强还原环境;其与奥陶系正常油-超重质油和雅克拉地区凝析油总体具有相似的生物标志化合物和碳同位素分布特征,反映均具有相似的油源;其等效镜质体反射率(Rc)值为1.7%,成熟度高于奥陶系重质油、寒武系挥发油,与邻区凝析油相当,处于高成熟阶段。综合生物标志化合物和碳同位素证据,推测TS5井震旦系油气源来自下寒武统玉尔吐斯组,其与上覆玉尔吐斯组泥页岩构成良好的储盖组合,喜马拉雅晚期来自周边较低部位玉尔吐斯组生成的高成熟凝析油气,沿斜坡运移至震旦系白云岩构造圈闭内形成了一定规模的凝析气藏。TS5井震旦系油气突破,发现了新的含油气层系,丰富了超深层油气成藏过程,为塔里木盆地超深层勘探指明了新的探索方向。

Quantitative research method for tectonization intensity:a case study in Tahe-Lunnan oilfield of Xinjiang

The research on tectonization intensity plays an important role in the analyses of basin evolution and hydrocarbon accumulation. At present, methods in this field are almost qualitative, and the quantitative one is still rarely reported. In this study, a quantitative research method for tectonization intensity is proposed. The research result on Tahe-Lunnan oilfield shows that this method can not only quantitatively express the tectonization intensity, but also qualitatively reflect the macroscopic deform property and the evolution history of strata. Therefore, it is an effective method for analyzing the characteristics of tectonization. In addition, the realization of the method also can provide qualitative information for studying the influence and control of tectonization on hydrocarbon accumulation.

Production evolution patterns and development stage division of waterflooding oilfields

The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle model. With the new model, the statistical correspondence between the production decline stage and the reserve-production imbalance is clarified,and the correlation of water cut with the recovery percent of recoverable reserves is discussed, providing quantitative basis of reservoir engineering for dividing development stages of oilfield and defining mature oilfields. According to the statistics of oilfields in eastern China, the time point corresponding to the reserve-production balance coefficient dropping to less than 1dramatically is well correlated the beginning point of production decline, thus the time when the reserve-production balance coefficient drops dramatically can be taken as the initiation point of production decline stage. The research results show that the water cut and the recovery percent of recoverable reserves have a good statistical match in the high water cut stage, and it is more rational to take both the start point of production decline stage and the water cut of 90%(or the recovery percent of recoverable reserves of 80%) as the critical criteria for defining a mature oilfield. Five production evolution patterns can be summarized as follows: growth–peak plateau–stepped decline, growth–stepped stabilizing–stepped decline, growth–stepped stabilizing–rapid decline, growth–peak plateau–rapid decline, and growth–continuous decline.

塔河油田走滑断裂与古岩溶耦合关系研究及其对奥陶系储层发育的影响

走滑断裂与古岩溶作用耦合关系方面的研究报道较少。本文通过对TH12518走滑断裂在奥陶系一间房组地层内构造样式时空叠加改造特征和不同期岩溶作用的研究,明确不同期次走滑断裂内幕结构与古地貌、古水系间的耦合关系。在TH12518走滑断裂在多期构造活动改造下,一间房组地层构造样式多次差异叠加,形成5种分段类型:Ⅰ型,拉分+平移+拉分段;Ⅱ型,拉分+平移+平移段;Ⅲ型,平移+挤压+拉分段;Ⅳ型,平移+挤压+平移段;Ⅴ型,逆冲推覆改造段。即加里东中期Ⅰ~Ⅲ幕形成平移段和拉分段;加里东晚期形成平移+挤压段、拉分+平移段、逆冲推覆段3种样式;海西早期发生“弯曲效应”,形成平移+挤压+平移段、拉分+平移+平移段、平移+挤压+拉分段、拉分+平移+拉分叠加构造样式。不同期岩溶地貌差异大。加里东中期Ⅰ幕岩溶台地水系欠发育;加里东中期Ⅱ-Ⅲ幕,北部抬升形成岩溶准平原,南部岩溶斜坡区发育近南北向地表水系及暗河;加里东晚期,岩溶斜坡区发育多组水系,沿北东东向断裂新形成北东东向暗河和地表水系。海西早期,岩溶斜坡发育大型曲流河。一间房组地层在不同岩溶期,不同区域不同类型段的岩溶作用不同。加里东中期Ⅰ幕整体发育开发式裸露型岩溶,沿断裂带下渗溶蚀,北北东向断裂拉分段溶蚀较强。加里东中期Ⅱ-Ⅲ幕北部发育开发式裸露型岩溶,南部为半开放式承压型岩溶,拉分段溶蚀进一步增强,Ⅱ幕还发育“下降型”埋藏断控岩溶。加里东晚期发育开发裸露型岩溶、半开放承压岩溶和“下降型”埋藏断控岩溶,北部受岩溶基准面控制,向下在寒武系顶面白云岩岩性界面岩溶作用受阻。南部不受基准面控制,向下至少溶蚀至寒武系阿瓦塔格组顶面,纵向上岩溶缝洞体分层明显。海西早期,发育半开放式承压型岩溶,除弯曲效应拉分段外,岩溶作用较弱。在空间上存在某一区域储层由某一期或多期关键岩溶期和关键岩溶方式控制决定,如覆盖区加里东中期Ⅱ幕“下降型”埋藏断控岩溶作用是奥陶系一间房组顶面缝洞型储层形成的关键因素。研究成果有助于为滚动开发实践提供地质依据。

塔河油田下寒武统烃源岩生排烃史差异演化及成藏效应

针对塔河奥陶系油藏多相态油气富集主控因素认识不清的问题,采用盆地模拟技术再现了塔河油田下寒武统烃源岩热演化史、生烃史及典型剖面油气运聚过程。研究表明:塔河地区下寒武统烃源岩从加里东早期进入成熟阶段,目前处于高成熟—湿气阶段,发育断续埋藏、持续埋藏和长期浅埋藏3种热演化模式,分别对应油气并举双峰型、油强气弱型、单峰型3种生烃模式。烃源岩热演化差异致使奥陶系油气发育多期充注、垂向疏导、侧向调整改造的演化历史,油气相态呈现轻质油藏—中质油藏—重质油藏的有序分布格局。塔河地区不同构造带下寒武统烃源岩热演化具有由北西向南东递增的趋势,与油气相态差异呈现明显的正相关性,体现出“源控”特征,喜山期控制了现今油气藏分布。研究发现,塔河油田盐下、托甫台生烃强度高,喜山期生烃总量相对较大,可作为下一步勘探开发的有利区。研究结果对塔河油田深层油气资源和目标评价有一定指导意义。