Geological characteristics of unconventional tight oil reservoir (10^(9) t): A case study of Upper Cretaceous Qingshankou Formation, northern Songliao Basin, NE China

The Daqing exploration area in the northern Songliao Basin has great potential for unconventional oil and gas resources,among which the total resources of tight oil alone exceed 109 t and is regarded as an important resource base of Daqing oilfield.After years of exploration in the Qijia area,Songliao Basin,NE China,tight oil has been found in the Upper Cretaceous Qingshankou Formation.To work out tight oil’s geological characteristics,taking tight oil in Gaotaizi oil layers of the Upper Cretaceous Qingshankou Formation in northern Songliao Basin as an example,this paper systematically analyzed the geological characteristics of unconventional tight oil in Gao3 and Gao4 layers of the Qijia area,based on the data of the geological survey,well drilling journey,well logging,and test.It is that three sets of hydrocarbon source rocks(K2qn1,K2qn2+3,and K2n1)develop in the examined area,and exhibit excellent type I and II kerogens,high organic matter abundance,and moderate maturity.The reservoir is generally composed of thin-bedded mudstone,siltstone,and sandstone,and presents poor porosity(average 8.5 vol.%)and air permeability(average 4 mD).The main reservoir space primarily includes intergranular pores,secondary soluble pores,and intergranular soluble pores.Three types of orifice throats were identified,namely fine throat,extra-fine throat,and micro-fine throat.The siltstone is generally oil-bearing,the reservoirs with slime and calcium become worse oil-bearing,and the mudstone has no obvious oil-bearing characteristics.The brittleness indices of the sandstone in the tight oil reservoir range from 40%to 60%,and those of the mudstone range from 40%to 45%,indicating a better brittleness of the tight oil reservoir.Based on the study of typical core hole data,this paper gives a comprehensive evaluation of the properties of the tight oil and establishes a tight oil single well composite bar chart as well as the initial evaluation system with the core of properties in the tight oil reservoir.This study has theoretical guiding significance and practical application value for tight oil exploration and evaluation in the Qijia area.

Unconventional Geochemical Exploration for Gold Deposits

Conventional geochemical exploration for gold deposits has not always been very satisfactory, especially for buried and blind ones. New considerations and methodology in sampling, analysis and interpretation have been developed in China during the past decade. Important considerations for unconventional gold exploration in this paper are that (1) gold is active in surface environments; (2) gold occurs not only as discrete grains, but also as ultrafine particles (submicron?to nanometer-sized particles of gold) and other complex forms; (3) regional low anomalies and superimposed anomalies over buried gold deposits are produced by ultrafine gold grains and other complex forms of gold. The methodology based on these considerations has been developed both in regional and in local geochemical exploration for gold. Examples of the preliminary application of these methods in two areas covered by transported overburden are given.

Coordinated Exploration Model and its Application to Coal and Coal-associated Deposits in Coal Basins of China

China is a top world producer of coal resources with numerous coal-rich basins country-wide that also contain coalbed methane(CBM),an unconventional natural gas resource.Recent exploration of coal and CBM resources has also led to the discovery of rare,precious,and scattered metal minerals,including sandstone-type U and Ga–Ge–Li.High-grade and industrial-value deposits have been discovered in the Ordos,Junggar,and other basins across China during exploration for coal resources.Application of coordinated exploration theories and techniques in multiple energy and coal-associated ore deposits,such as coal and unconventional natural gas in coal,achieves efficient and practical exploration of natural resources.Based on the systematic study of accumulation and occurrence of coal and coal-associated mineral resources in coal basins,the basic idea of coordinated exploration for coal and coal-associated deposits is proposed,and multi-targets and multi-methods based on a coordinated exploration model of coal-associated deposits is developed.Coordinated exploration expands the main exploration objective from coal seams to coal-associated series,extending the exploration target from targeting coal only to coal-associated deposits.Entrance times for exploration are decreased to realize coordinated exploration for coal,unconventional natural gas and syngenetic/associated mineral resources in coal by implementing a’one-time approach’―one time in and out of a coal seam to minimize disturbance and time needed for extraction.According to the differences of geological background in China’s coal basins,four coordinated exploration model types,including co-exploration of coal and coal-associated unconventional natural gas,coal and solid minerals,coal and metal minerals,and coal with water resources are established.Other models discussed include a multi-target coordinated exploration model for the combination of coal,coal-associated gas,solid minerals,and metal minerals accordingly.The exploration techniques of coal and coal-associated resources include regional geological investigation and research and synthetic application of other techniques including seismic surveys,drilling,logging,and geochemical exploration.Particularly,applying the’multi-purpose drill hole’or reworking coalfield drill holes into parameter wells,adding sample testing and logging wells,determining gas-bearing layers by logging and gas content measurement,jointly measuring multiple logging parameters,sampling,and testing of coal-strata help in the exploration and evaluation of coal resources,coal-associated unconventional natural gas resources,and coal-associated element minerals.Accordingly,a system of integrated Space–Air–Ground exploration techniques for coordinated exploration of coal and coal-associated minerals is established.This includes high-resolution,hyperspectral remote-sensing technique,high-precision geophysical exploration and fast,precise drilling,testing of experimental samples,as well as coordinated exploration and determination methods of multi-target factors,multi-exploration means,multi-parameter configuration and optimization,big data fusions and interpretation techniques.In recent years,the application of this integrated system has brought significant breakthroughs in coal exploration in Inner Mongolia,Xinjiang and other provinces,discovering several large,ten-billionton coalfields,such as the Eastern Junggar and Tuha basins,and also in exploration and development of CBM from lowrank coals in Fukang,Xinjiang,discovery the Daying U Deposit in Inner Mongolia,the Junggar Ultralarge Ga Deposit,Lincang,Yunnan,and the Wulantuga,Inner Mongolia,Ge-bearing coal deposits,and the Pingshuo Ultralarge Li–Ge Deposit.

Experimental Study of Induced Polarization Effect in Unconventional Reservoir Rocks

Unconventional hydrocarbon reserves substantially surpass those of conventional resources and therefore are extremely economically attractive. However, exploration and production of uncon-ventional reserves is challenging. This paper demonstrates that one can observe significant induced polarization effects in shale reservoir rocks, which can be used in exploration for unconventional reserves. The generalized effective-medium theory of induced polarization (GEMTIP) was used to model the complex resistivity of shale rocks. We demonstrate that GEMTIP modeling provides an evaluation of mineral composition and volume fractions in rock samples. We have conducted spectral induced polarization (IP) measurements using different types of shale rocks to test the feasibility of the IP method and GEMTIP modeling for studying unconventional hydrocarbon (HC) reservoir rocks.

Analysis of the world oil and gas exploration situation in 2021

The global exploration investment, new oil and gas discoveries, exploration business adjustment strategies of oil companies in 2021, and future favorable exploration domains are systematically analyzed using commercial databases such as IHS and public information of oil companies. It has been found that the world oil and gas exploration situation in 2021 has continued the downturn since the outbreak of COVID-19. The investment and drilling workload decreased slightly, but the success rate of exploration wells, especially deepwater exploration wells, increased significantly, and the newly discovered reserves increased slightly compared with last year. Deep waters of the passive continental margin basins are still the leading sites for discovering conventional large and medium-sized oil and gas fields. The conventional oil and gas exploration in deep formations of onshore petroliferous basins has been keeping a good state, with tight/shale oil and gas discoveries made in Saudi Arabia, Russia, and other countries. While strengthening the exploration and development of local resources, national, international, and independent oil companies have been focusing on major overseas frontiers using their advantages, including risk exploration in deep waters and natural gas. Future favorable exploration directions in the three major frontiers, the global deep waters, deep onshore formations, and unconventional resources, have been clarified. Four suggestions are put forward for the global exploration business of Chinese oil companies: first, a farm in global deepwater frontier basins in advance through bidding at a low cost and adopt the “dual exploration model” after making large-scale discoveries;second, enter new blocks of emerging hot basins in the world through farm-in and other ways, to find large oil and gas fields quickly;third, cooperate with national oil companies of the resource host countries in the form of joint research and actively participate exploration of deep onshore formations of petroliferous basins;fourth, track tight/shale oil and gas cooperation opportunities in a few countries such as Saudi Arabia and Russia, and take advantage of mature domestic theories and technologies to farm in at an appropriate time.

The mechanism of unconventional hydrocarbon formation: Hydrocarbon self-sealing and intermolecular forces

The successful development of unconventional hydrocarbons has significantly increased global hydrocarbon resources, promoted the growth of global hydrocarbon production and made a great breakthrough in classical oil and gas geology. The core mechanism of conventional hydrocarbon accumulation is the preservation of hydrocarbons by trap enrichment and buoyancy, while unconventional hydrocarbons are characterized by continuous accumulation and non-buoyancy accumulation. It is revealed that the key of formation mechanism of the unconventional reservoirs is the self-sealing of hydrocarbons driven by intermolecular forces. Based on the behavior of intermolecular forces and the corresponding self-sealing, the formation mechanisms of unconventional oil and gas can be classified into three categories:(1) thick oil and bitumen, which are dominated by large molecular viscous force and condensation force;(2) tight oil and gas, shale oil and gas and coal-bed methane, which are dominated by capillary forces and molecular adsorption;and(3) gas hydrate, which is dominated by intermolecular clathration. This study discusses in detail the characteristics, boundary conditions and geological examples of self-sealing of the five types of unconventional resources, and the basic principles and mathematical characterization of intermolecular forces. This research will deepen the understanding of formation mechanisms of unconventional hydrocarbons, improve the ability to predict and evaluate unconventional oil and gas resources, and promote the development and production techniques and potential production capacity of unconventional oil and gas.

四川盆地渝西大安地区灰质源岩气勘探突破与资源潜力

四川盆地渝西大安地区茅口组一段(茅一段)灰质源岩气勘探取得了重大突破,对灰质源岩气的源内非常规勘探具有重要借鉴和示范意义。DB1H井是四川盆地针对茅一段暗色灰质源岩非常规气藏评价部署的首口水平井,通过酸化压裂试气获得高达55.6×10^(4) m^(3)/d的测试产量。系统介绍了渝西大安地区茅一段灰质源岩气的发现历程,展望了四川盆地茅一段灰质源岩气的资源前景。通过对渝西大安地区茅一段灰质源岩地质特征研究,认为该层系岩性主要为中缓坡相深灰色—黑灰色富有机质泥晶生屑灰岩,且区域稳定分布,是中国南方中上扬子地区重要的海相灰质源岩地层。茅一段灰质源岩气整体经历了富有机质碳酸盐岩沉积—成岩—成烃—成储—成藏—赋存“源内一体化演变”成藏过程,具有“源储一体、原位富集、连续型展布”的成藏特征。以微米级为主体的源内微观孔隙及与断层伴生的溶蚀孔洞、微缝网体系为气体主要储集空间,构成了基质孔隙型(原生型)和裂缝—孔隙型(改造型)两类储层,建立了“源储一体为主兼构造转折带短距离运移富集”的灰质源岩气成藏模式和甜点评价体系。富有机质暗色灰质源岩的发育、有利的古隆起和现今背斜构造背景,及与古断层有关的断控型岩溶、张性应力微裂缝的发育叠置,为茅一段灰质源岩新型储层富集高产的关键。初步估算四川盆地茅一段灰质源岩气资源量可达2×10^(12)m^(3),将成为盆内现实增储上产战略意义的非常规勘探新领域。

细粒沉积岩典型低阻油层成因及甜点分布

细粒沉积岩已成为非常规油气勘探的重要目标,普遍发育了低电阻率油气层。利用测井、录井、地震和薄片电镜测试等资料,结合相控储层参数分布技术,揭示了细粒沉积岩典型低阻油层成因机制,并提出了3类基于低阻成因的甜点分布规律。研究表明:①低阻油层成因主要包括大比表面积、高含量伊/蒙混层矿物、发达的微孔隙网络及其内部束缚水、高矿化度水以及高含量导电矿物等5个方面。②识别出了3类细粒沉积岩低阻类型,包括高泥质含量致密型低阻油层(致密低阻型)、高含量导电矿物型低阻油层(导电矿物低阻型)和疏松砂岩强连通水网型低阻油层(强连通水网导电低阻型),并在此基础上进行了成因分析。③明确了低阻隐蔽油层的甜点分布特征。致密型低阻油层甜点主要发育在电阻率相对较高的储层中,导电矿物型低阻油层甜点主要发育在白云质粉砂岩基质溶蚀段与白云质泥/页岩裂缝发育段,而强连通水网导电型低阻油层甜点主要发育在具有双模态孔隙结构的极细粒岩性中。研究结果对于指导下一步细粒沉积岩储层油气勘探意义重大。

中国油气勘探开发成就与未来潜力:深层、深水与非常规油气——专访中国科学院院士、石油地质与构造地质学家贾承造

中国石油工业上游取得了举世瞩目的成就:在资源困难条件下石油产量保持在年产量2×108 t水平,天然气产量快速增长,2022年天然气产量2200×108 m3,成为世界第4大产气国。塔里木盆地克拉2气田的发现是中国天然气勘探史的标志性成果,主要归功于对塔里木盆地构造性质和库车含油气系统的杰出研究和资源预测。中国的风险勘探工程、岩性地层油气藏勘探工程,以及国家科技重大专项“大型油气田及煤层气开发”极大地推动了中国油气勘探开发,提升了中国石油工业勘探开发科技水平,为中国油气产量增长作出了重大贡献。中国石油工业上游未来的发展潜力在深层、深水和非常规油气的勘探开发,以及老油气田提高采收率和CCS-CCUS业务。未来石油工业的发展将更多地依靠深层、深水与非常规油气地质理论技术的创新、钻井压裂和海洋工程施工能力的建设、更高效的组织管理能力和献身于中国石油工业的年轻一代。

动态图像法检测压裂石英砂支撑剂粒度粒形

为了解决水力压裂石英砂支撑剂粒度粒形人工检测效率低、随机误差大且无法在线检测等难题,引入动态图像检测方法,不仅可以同时测量颗粒粒度、粒形,还为支撑剂在线检测开拓新思路。首先开展了石英砂动态图像处理算法研究,实现了石英砂图像中的颗粒提取及分析计算,精准求得石英砂粒度粒形参数,并设计了测试系统;其次与传统筛分法、电镜法等测量手段对比测试了20/40目、40/70目、70/140目等3种常用支撑剂,测量效率提高近200倍,重复性误差在1.7%以内,准确性误差在1.5%以内。结果表明,动态图像法可以解决人工检测效率低、随机误差大等难题,并可将检测系统安装在石英砂制备生产线上或水力压裂施工现场,实现在线测试,全面提升压裂入井材料质量管控水平。

2022年中国油气勘探形势及2023年展望

2022年,为应对世界百年未有之大变局、国际能源市场剧烈震荡等复杂形势,国内油气勘探企业和油气地质调查队伍均加大油气勘探投资力度,取得诸多油气新发现新突破。为了确保今后一个时期中国油气勘探的高质量、可持续发展,梳理了中国常规与非常规油气资源情况,分析了2022年中国油气勘探的主要特点和新亮点,结合中国油气资源潜力,展望了2023年油气勘探前景。研究结果表明:①2022年中国油气勘探的主要特点表现为中国油气勘探资金投入和油气产量回暖明显、新发现集中在已证实成藏组合的周边和深部、成熟探区的非常规油气勘探成效显著、前沿石油地质理论和技术引领油气勘探新突破;②塔里木盆地富满油田奥陶系断控高能滩、四川盆地东南部二叠系天然气和深层页岩气、东部老油田页岩油勘探等领域取得重大突破;③2023年中国油气勘探有望在深层及深海油气勘探、大型含油气盆地周缘、北方海相页岩油气和海陆过渡相页岩气等领域取得新突破。

依据物质凝聚态分类油气井用转向压裂暂堵剂

暂堵剂阻止压裂液进入不希望进入的通道而成为油气井转向压裂的关键手段之一。目前零星报道的分类,不利于现场准确选择暂堵剂提高转向压裂成功率。200多篇文献调研的暂堵剂中,有的暂堵剂改变裂缝内压力分布,有的暂堵剂改变岩石力学参数,2种机制均能降低裂缝尖端的能量释放率,进而提高裂缝承压能力实现转向。这些暂堵机制皆因物质凝聚态不同所致。遂按凝聚态将暂堵剂分为固态、液-固态、液态等3大类23种,涵盖所有的暂堵剂,提高涵盖率17%,实现了全面覆盖;暂堵剂的密度、粒径、适用温度、解封时间、封堵压力和渗透率恢复值,关联压裂液的密度和排量、封堵孔径或缝宽、储层温度、焖井返排时间、储层应力状态及物性,提高了现场选择暂堵剂的针对性。依据物质凝聚态分类油气井用转向压裂暂堵剂,解决了目前分类方法无法涵盖全部产品、不利于现场准确选择的难题。

全球油气勘探开发趋势及对我国油气行业的启示

通过对近20年来全球油气勘探开发投资、油气勘探活动、油气开发活动3个方面进行定性和定量分析,总结提炼出6点油气勘探开发趋势,并提出我国油气行业实现科学可持续发展的启示。预计未来5年全球油气勘探开发投资将回暖,但增速难达2003–2014年时期;勘探投入力度不足,可能引发资源接替问题;天然气勘探开发更受重视;深水油气资源对增储的贡献更加突出;非常规油气地位继续上升。因此,建议我国石油企业应继续保持较高的油气勘探力度,进一步加大天然气勘探开发,加强深水和非常规油气资源开发力度。

改进原型网络法诊断抽油机故障

示功图是判断有杆抽油机工作状况的重要方法。常见故障工况因数据量多使其诊断准确率可达到99%,不常见的故障数据稀少,导致诊断准确率仅有90%~92%。为了提高数据量较少时抽油机故障诊断准确率,提出了基于压缩激励模块(Squeezeand-Excitation)改进原型网络的抽油机故障诊断方法。首先引入残差连接以及注意力模块对示功图特征进行提取,然后将不同类别的示功图像映射到特征空间,经过度量距离后输入Softmax分类器,实现小样本条件下抽油机故障诊断。研究结果表明,改进的原型网络模型在不同小样本数据集上分类准确率均提高。尤其在样本数据图小于50张时,比AlexNet及ResNet34模型对正常、供液不足、泵上碰、气影响、游动阀漏失、砂阻等6种故障类型诊断准确率提高3%~20%。

Some key issues on the unconventional petroleum systems explora­

Oil and gas currently still hold a leading role in the global energy mix.The recent drastic increase in unconventional oil and gas production contributes significantly to strike a balance between the global demand and supply of oil and gas.However,a range of important fundamental questions about the unconventional oil and gas resources have not been adequately answered.Little is known about the distribution and accumulation patterns,as well as the exploration and development characteristics of unconventional oil and gas.The current status of global oil and gas exploration was reviewed and four key theoretical issues regarding the unconventional oil and gas geology were identified:(1)the traditional concept and definition of“petroleum system”needs to be revisited.The concept of a“holistic-process accumulation”model of a“total petroleum system”in petroliferous basins was proposed to analyze the unconventional hydrocarbon accumulation mechanisms from four key aspects of quantitative studies on hydrocarbon generation-expulsion-migration-accumulation processes.(2)The second issue is related to fine-grained sedimentary system and sedimentary facies of tight reservoirs.Through analyzing the relationship between fine-grained sediments and unconventional hydrocarbon accumulation,three research integration areas were put forward.(3)The third issue is on the micro-nano pore system and fluid phase behavior in shales and tight reservoirs.Five aspects of micro-nano pore system were identified to focus on unconventional hydrocarbon research,and the characteristics of micro-nano pore development and fluid phase behavior in micro-nanopores were elucidated.(4)The fourth issue is related to unconventional hydrocarbon accumulation patterns and resource evaluation.Based on the characteristics of unconventional hydrocarbon accumulation,an evaluation system for unconventional hydrocarbon resources was established and optimized.

Theory, Technology and Practice of Unconventional Petroleum Geology

0 INTRODUCTION The breakthroughs in unconventional petroleum have a great impact on world petroleum industry and innovation in petroleum geology(Dou et al,2022;Jia,2017;Zou et al.,2015b,2014a;Yerkin,2012;Pollastro,2007;Schmoker,1995).The exploration and development evolution from conventional petroleum to unconventional petroleum and more and more frequent industrial activities of exploring petroleum inside sources kitchen have deepened theoretical understanding of unconventional petroleum geology and promoted technical research and development(Jia et al.,2021,2017;Jin et al.,2021;Zhao W Z et al.,2020;Ma Y S et al.,2018,2012;Zou et al.,2018b,2016,2009;Dai et al.,2012).We have introduced and extended the theory of continuous hydrocarbon accumulation since 2008 and published several papers/books(in Chinese and English)with respect to unconventional petroleum geology since 2009,basically forming the theoretical framework for this discipline(Yang et al.,2022a,2021a,2019a,,2015a;Zou et al.,2019c,2017b,2014a,,2013a).In this paper,we present the background of unconventional petroleum geology,review the latest theoretical and technological progress in unconventional petroleum geology,introduce relevant thinking and practices in China,and explore the pathway of unconventional petroleum revolution and multi-energy coordinated development in super energy basins,hopefully to promote the unconventional petroleum geology and industry development.

页岩气及其勘探研究意义

与传统意义上的泥页岩裂缝气并不完全相同,现代概念的页岩气是主体上以吸附和游离状态同时赋存于具有生烃能力泥岩及页岩等地层中的天然气聚集,具有自生自储、吸附成藏、隐蔽聚集等地质特点。美国的页岩气勘探取得巨大成功,是投入工业性勘探开发的三大非常规天然气类型之一,目前已形成了区域性页岩气勘探开发局面。中国的页岩气研究正在起步,许多盆地及研究区具有页岩气成藏的地质条件。与美国东部地区页岩气成藏地质条件进行初步对比,中国南方具有有利的页岩气发育条件,开展页岩气研究具有重要意义。

中国非常规天然气勘探雏议

非构造控藏是包括煤层气、页岩气、根缘气、水溶气、水合物等类型在内的几乎所有非常规机理天然气聚集的共同特征,特殊的赋存状态和富集特点使它们在盆地空间内构成了依次渐变的分布序列。其中,根缘气、煤层气和页岩气的勘探开发价值较高,也是目前非常规天然气勘探中的主要类型。致密储层中的根缘气是中国非常规天然气勘探的主要类型,主要在中西部地区具有良好的发育地质条件,砂岩底部含气是其识别和勘探的主要特点。煤层气是吸附状态天然气富集的代表类型,对于大中小型盆地的油气勘探均具有重要意义。页岩气具有煤层气和根缘气在成藏意义上的双重特征,吸附机理的存在提高了页岩气资源量并延伸了勘探领域,页岩气可能是中国南方地区油气进一步勘探的重要突破口。中国非常规天然气具有广阔的勘探前景,加强理论、技术研究及交流,将能够更好地促进非常规天然气的勘探与发展。

页岩气是潜力巨大的非常规天然气资源

通过对北美页岩气藏的深入研究并系统总结其勘探开发历史与成功经验,指出页岩气藏是典型的非常规天然气藏。探讨了页岩气藏在地质特征、开发特征上与常规天然气藏的明显差异。北美油气生产商把页岩气藏作为重要天然气开发目标,其有效勘探开发的关键在于有政策引导和水平井、水力压裂等先进钻、完井技术的成功应用。借鉴其经验,认为我国对页岩气的研究与勘探开发尚处于探索阶段,存在古生界海相与中、新生界陆相两大页岩气勘探开发领域,页岩气资源潜力巨大,在地质理论和钻、完井等生产技术发展的推动下,将成为中国现实的天然气资源。建议加快我国页岩气资源战略调查,制定优惠政策,加强对外合作,推动我国页岩气勘探开发技术和产业化发展。

2021年世界油气勘探形势分析与思考

基于埃士信能源咨询公司(IHS)等商业数据库及油公司公开信息,对2021年全球勘探投资、油气新发现、油公司勘探业务调整策略、未来有利勘探领域等方面进行了系统分析。结果表明:2021年世界油气勘探形势依然延续新冠疫情以来的低迷态势,投资及钻井工作量同比小幅下降,但探井成功率特别是深水探井成功率明显提升,油气新发现储量同比略有增加;海域被动陆缘盆地深水仍为常规大中型油气田发现的主战场,陆上富油气盆地深层常规油气精细勘探依然延续良好态势,沙特、俄罗斯等多个国家致密油气及页岩油气勘探有新的发现;国际、国家及独立石油公司均在加大本土资源勘探开发力度的同时,利用自身优势持续聚焦境外深水、天然气等核心领域;全球海域深水、陆上深层和非常规油气3大领域是未来有利油气勘探方向。建议中国油公司跨国勘探业务:①通过投标超前低成本进入全球深水前沿盆地,发现规模油气后采用“双勘探模式”经营;②通过参股等多种方式进入全球新兴热点盆地未钻区块,快速发现规模油气田;③以联合研究形式与资源国国家石油公司合作,积极进入陆上富油气盆地深层;④重点关注沙特、俄罗斯等国家致密油气及页岩油气勘探合作机会,利用国内成熟理论技术优势择机进入。