The discoveries, theoretical and technical progress of shale oil exploration of the 7th member of Triassic Yanchang
Formation (hereinafter referred to as Chang 7 member) are summarized during the 13th Five-Year Plan period. The resource potential is predicted, and the exploration targets are proposed during the 14th Five-Year Plan period. There are four types of shale
oil in Ordos Basin, including gravity flow interlayered type, delta front interlayered type, laminar shale type and laminated shale
type. Among them, a one-billion-ton-level Qingcheng Oilfield has been discovered in the central lake basin, and large-scale reserves of 5×108 t preliminarily been defined in the peripheral lake basin; In addition, promising signs have been observed in the
risk exploration of laminar shale type shale oil. The study results show that high-quality source rocks supply a large amount of
liquid hydrocarbon for shale oil enrichment. Multiple types of reservoir space and continuous high-pressure charging caused by
hydrocarbon generation pressurization inside the source rock are the key to the large-scale oil accumulation and high yield of
sweet spots. The widely developed sandy deposits in deep water areas are sweet spots for shale oil exploration. A series of supporting technologies, such as comprehensive evaluation technology of geological-engineering sweet spots, anti-collapse fast and optimal drilling and completion technology of cluster horizontal well, and “advanced energy storage and subdivision cutting”
volume fracturing technology of horizontal well, are important guarantees for the discovery of large-scale shale oil reserves. The
fruitful exploration results achieved during the 13th Five-Year Plan period support to strengthen the confidence in expanding the
scale of gravity flow interlayered type shale oil enrichment area in the central lake basin and exploring new fields of delta front
interlayered type shale oil in the peripheral lake basin. Meanwhile, new supporting technology is actively researched, so as to
provide a solid resource foundation for the high-quality and rapid development of shale oil exploration of Changqing Oilfield
Company.

During the 13th Five-Year Plan period, PetroChina has kept up with the development trend of advanced artificial intelligence and major needs in the fi eld of geophysical prospecting, planned in advance and actively deployed researches, which highly promotes the development of intelligent geophysical technology. Till now, two major technology series of intelligent seismic processing and interpretation have been developed, and intelligent seismic software platform and label data set software been released. Meanwhile, PetroChina has led an innovative “6+1” intelligent “industry-university-research institute” alliance for geophysical exploration consisting of Peking University, etc., which effectively promotes the innovation of PetroChina intelligent geophysical technology and achieves the synchronous development with the international intelligent geophysical technology. During the 14th Five-Year Plan period, PetroChina will focus on the strategy of “digital transformation and intelligent development” and clarify the development plan and direction of “123456”, so as to conform to the global energy transformation and intelligent development trend. Based on module replacement, PetroChina will actively explore process regeneration and promote the innovative development and application of intelligent seismic processing and interpretation technology. In labor-intensive scenarios, intelligent module replacement will be implemented to improve effi ciency of seismic processing and interpretation, support industrial production to improve effi ciency and reduce costs. Meanwhile, in technology-intensive scenarios, intelligent process will be regenerated to improve accuracy of seismic processing and interpretation, forming a world-class series of intelligent seismic processing and interpretation technologies, and realizing the self-reliance of intelligent geophysical exploration technology, which supports to comprehensively promote the intelligent development of geophysical business of PetroChina, ultimately achieves the intelligent petroleum exploration, and provides realtime guidance for horizontal well drilling.

The petroleum exploration in most of the domestic petroliferous basins has entered or will step into the stage of unconventional oil and gas exploration and development. The wireline logging technologies should be promoted to meet the development trend timely and effectively. The current situation, challenges and new requirement of logging technology in China are systematically analyzed by considering the characteristics of unconventional reservoir, oil and gas reservoir and engineering conditions. Finally, development countermeasures are proposed in detail by benchmarking international leading logging technology, which are: (1) Improve the performances of conventional wireline logging tools. The high-precision, high-resolution and high-safety conventional logging tools should be developed and put into production, with vertical resolution of 5-10 cm, density logging accuracy of 0.01-0.015 g/cm³. The high-yield controllable neutron tube technology will enable the safe density and neutron logging without radioactive source. (2) Develop high-performance imaging logging technology. Firstly, focus on the technology of 2D NMR logging with short echo interval (no more than 0.3 ms), high vertical resolution (about 10 cm), high signal-to-noise ratio (more than 8), and simultaneous detection of longitudinal and transverse relaxation; Secondly, research fi ne calculation of mineral compositions and accurate determination of fl uid properties applicable for tight reservoirs, such as the full spectrum of elements, multi frequency dielectric log, downhole real-time fl uid analysis and pressure measurement tools, and horizontal well multiphase fl ow imaging logging technology; Thirdly, promote 3D acoustic logging technology with the capabilities of fi ne azimuth resolution and ultra-far detection to describe the stratigraphic structure near the borehole of horizontal well, fault system, and spatial distribution of hydraulic fractures. (3) Speed up the research on high-performance through-pipe logging tools. The logging items should include conventional logging, electric imaging logging and array acoustic logging. The element full spectrum logging should gradually be supplemented, with its data accuracy and vertical resolution consistent with those of wireline logging data. The density and neutron logging tools should adopt miniaturized, high-yield and controllable neutron tube technology. The miniaturization of NMR logging should be enhanced to develop through-pipe NMR logging with its technical performance matching with that of wireline logging. (4) Emphasize the research on near bit and far-detection edge LWD technology. First is to establish a complete LWD logging series including GR and resistivity azimuth imaging logging, with the distance of less than 1 m between the detection point and drill bit; Second is azimuth far-detection edge technology with radial detection range of 20-30 m and azimuth resolution of at least 90°; Third is the forward-looking detection technology that can distinguish the formation interface or fault more than 5 m in front of the bit.

There many deficiencies of the existing information system of oil and gas enterprises, such as the inconsistent data standards,the scattered sources of energy effi ciency data, redundant data construction, and diffi culties in data circulation. By analyzing the causes and formulating countermeasures, a multi-source data fusion model and method are developed based on various verifi cation rules for different energy effi ciency metadata, realizing the actual application and feasibility verifi cation of energy effi ciency data fusion, which makes active progress for the subsequent construction of a fusion system of oil and gas production and energy effi ciency management.

The deep-water area of Qiongdongnan Basin has abundant oil and gas resources. A giant gas fi eld with resources of over 100 billion cubic meters has been discovered in Ledong-Lingshui Sag in the western deep-water area. While no breakthrough has been made in Baodao- Changchang Sag in the eastern deep-water area due to the great burial depth, poor reservoir physical properties and poor understanding of hydrocarbon accumulation conditions. Recently, a risk exploration Well BD21, located at the northern fault terrace zone in Baodao Sag, obtained high-yield condensate oil and gas production of 200.2m³/d and 73.12×10⁴m³/d in the 3rd member of Lingshui Formation, which was a remarkable breakthrough in the eastern deep-water area in recent 30 years. Based on the drilling results of Well BD21, geological conditions and enrichment law of hydrocarbon accumulation are systematically summarized in the northern fault terrace zone in Baodao Sag. Study results show that a large-scale source rock of Yacheng Formation is developed with high maturity and strong capacity of hydrocarbon generation. The fault activity was weak during the two stages of hydrocarbon charging, and the tectonic evolution matched well with the timing of hydrocarbon supply. The high-effi ciency hydrocarbon migration pathways are formed by the combination of reservoir and faults which connect with source rock in both vertical and short-distance lateral directions. The regional caprock covers the whole spatial range of hydrocarbon generation, migration and accumulation, providing good sealing capacity. The northern fault terrace zone is favorable exploration target in Baodao Sag, which shows great potential of large-scale structural-lithologic oil and gas reservoirs in deep-water slope zone.

The Middle Triassic Leikoupo Formation is a major strategic replacement fi eld for petroleum exploration of PetroChina Southwest Oil and Gas Field Company in Sichuan Basin. The exploration situation is changing, and the rule of reservoir distribution in basin scale is necessary to be identifi ed, so as to provide guidance for gas exploration in the near future. The lithofacies paleogeography within sequence framework is further understood and reservoir characteristics are comprehensively analyzed by using a large number of core samples, well logging, seismic and outcrop data. The results show that: (1) It was a limited platform environment in Sichuan Basin during the deposition of Leikoupo Formation. The formation is subdivided into four tertiary sequences, and the favorable reservoirs are mainly developed in L1 1(1st sub-member of the 1st member of Leikoupo Formation), L33 and L43 sub-members of transgressive system tract; (2) The paleogeographic pattern of “one subsag and two uplifts” during the deposition of Leikoupo Formation controlled the distribution of beach reservoir, in which it was composite superimposed in the piedmont of Longmen Mountain in the western basin while it was migration superimposed of themarginal beach body of gypsum salt lake in the eastern basin; (3) There are two types of reservoirs of Leikoupo Formation, i.e., the faciescontrolled reservoir and karst reservoir. The former is dominated by grain beach dolomite and microbial dolomite, which is mainly developed in the basin margin and paleo highs inside the basin, while the latter is developed in the superimposed area of favorable facies zones and karst residual mounds. Finally, the favorable exploration targets are proposed by comprehensively considering source rocks, reservoir types and trap conditions, including grain beach dolomite and microbial dolomite reservoirs of L3 and L4 members in Jiange-Jiangyou-Mingshan area, beach dolomite reservoirs of L1 member in Ziyang-Nanchong area and the western margin of Luzhou paleo uplift, and karst reservoir in central Sichuan region.

The deposition conditions, sedimentary characteristics and deposition pattern of lowstand system tract sandstone are
analyzed and hydrocarbon accumulation conditions studied, so as to identify the development degree of lowstand system tract
sandstone of Qingshuihe Formation in Fukang Sag in Junggar Basin and its exploration potential. The study results show that base
Cretaceous Qingshuihe Formation is a third-order sequence boundary, and multi-stage slope breaks are developed near the
depo-center of Fukang Sag, providing favorable conditions for the deposition of lowstand system tract sandstone. Multi-stage
lowstand system tract sandstones are developed below the slope break of large-scale depressed lake basin, with large thickness,
widespread area, superior reservoir physical property and lateral sealing capacity, which have good conditions for developing
lithologic traps. In addition, two sets of faults are developed in deep and shallow formations, forming a “Y” shaped configuration
in vertical direction, and connecting source rock with lowstand system tract sand bodies. As a result, the lowstand system tract fan
sand body in the study area has excellent hydrocarbon accumulation conditions, which is the most favorable field for lithologic oil
reservoir exploration in the near future.

The shale gas resources are abundant of the Lower Cambrian in southern China, which is expected to be a major replacement fi eld for increasing reserves and production. However, geological conditions of the Lower Cambrian are more complex than those of Silurian shale gas. By taking the Lower Cambrian Hetang Formation in the southern Anhui of lower Yangtze area as study object, the geological characteristics and main controlling factors of shale gas accumulation of the Lower Cambrian are studied based on well drilling, logging, core sample, outcrop and lab test data. The results show that the effective hydrocarbon source conditions, reservoir conditions and preservation conditions are the basis for shale gas accumulation, and the proper dynamic coupling and space-time confi guration of the three are the key to shale gas enrichment. (1) The remained hydrocarbon is material basis for shale gas accumulation, and the degree of thermal evolution is the main factor affecting hydrocarbon expulsion effi ciency; (2) The degree of thermal evolution and preservation conditions jointly control the shale gas enrichment. The best window for the coupling of gas generation and reservoir occurs when R_o ranges from 1.8%-3.2%, and high pressure to overpressure formation is conducive to the maintenance of pores; (3) The preservation conditions are the key factors for the formation of shale gas reservoir. The tight roof and fl oor conditions and lateral reverse faults are favorable for the formation of “sealing box”, and the burial history of “late hydrocarbon generation and late tectonic uplift” is conducive to continuous hydrocarbon generation and slow down gas escape. The main target of shale gas exploration of the Lower Cambrian is structural stable areas with weak reformation and moderate thermal evolution.

The Upper Triassic Baiguowan Formation is a major shale series in Mishi Sag in Xichang Basin. The shale distribution
characteristics, geochemical characteristics, reservoir properties, gas bearing properties and preservation conditions are studied by
geological survey, systematic coring, core observation, and lab test, so as to investigate its geological conditions and exploration
potential of shale gas. Furthermore, these parameters are compared with other domestic continental shale series that have obtained gas discoveries. The results show that: (1) The organic rich shale of Baiguowan Formation is relatively developed in Mishi Sag,with large thickness, moderate organic carbon content, moderate maturity, high content of brittle minerals, high porosity and good gas bearing property, which has favorable geological conditions for shale gas accumulation; (2) The key parameters such as porosity,TOC, Ro and gas content of Baiguowan Formation shale in Mishi Sag are basically consistent with those of continental
shale that have obtained gas discoveries in China; (3) By comprehensively considering the development degree of organic rich
shale, burial depth, preservation and surface engineering conditions, five favorable areas of Tergo, Qiliba, Lewu, Sikai and
Xichang North are selected for shale gas exploration of Baiguowan Formation in Mishi Sag, which have great exploration and
development potential.

The heavy oil reservoir varies greatly from conventional oil reservoir in terms of oil properties, oil-water contact and preservation mechanism, and its oil accumulation process is extremely complicated. Taking the LD16 oil-bearing structure in Liaodong Bay Depression in Bohai Sea area as an example, the main characteristics of heavy oil reservoir is summarized in this study by using logging, core description, seismic and geochemical analysis data. Based on the characterization of reservoir heterogeneity and stereoscopic fault analysis, a quantitative migration simulation technique combining the charging section and reservoir heterogeneity is proposed to fi nely describe the hydrocarbon migration pathway, and further to study the heavy oil accumulation process. The results show that: (1) The active rate and curvature shape of faults determine the effective hydrocarbon migration section in fault zone; (2) The reservoir physical property and structural morphology jointly determine the dominant migration pathway of heavy oil, and the amount of oil charging and high porosity/permeability zone result in the irregular distribution of heavy oil; (3) The heavy oil reservoir is formed by the migration and adjustment of crude oil along the fault that was primarily degraded of Dongying Formation paleo oil reservoir during the neotectonic movement. The stable caprock and the abrupt increase of oil viscosity due to the decrease of temperature and pressure are the key factors for hydrocarbon accumulation in glutenite reservoir of Guantao Formation.

The structural-lithologic reservoir has the characteristics of thin thickness of sand body, rapid lateral change of reservoir and complex fault boundary. Therefore, the seismic prediction and boundary description of this oil reservoirs are challenging with low accuracy. In order to improve the prediction accuracy of thin sand reservoir, a seismic data processing method is innovatively proposed in this study by using steerable pyramid decomposition technology, which mainly includes the creation of pyramid structure (image decomposition) and image reconstruction after decomposition. The multi-scale decomposition and combination of seismic data allow to extract the geological body information in different scales and directions. Then the combination of seismic data of different scale is selected based on requirements of geological body description, so as to highlight and describe the characteristics of geological body from macro and micro perspectives. Finally, the seismic attributes and seismic inversion study are carried out on seismic data processed by this method. The reservoir prediction results are more in line with the rules of geological body when seismic data are selected with proper scale, avoiding the limitations of describing macro geological rules by using small-scale data and the uncertainty of characterizing micro heterogeneity of sand body by using largescale data.

The Lower Paleozoic dolomite reservoir in sub-salt and buried hill is widely distributed in Tarim Basin, with multiple types of oil and gas reservoirs, which is the characteristics of typical superimposed composite basin and have good prospects for petroleum exploration. Fracture-vuggy type reservoir is the most representative and favorable among dolomite reservoirs. Fine evaluation of fracture-vuggy type reservoir is helpful to improve geological understandings and reservoir identifi cation in the region. First, the fracture-vuggy type reservoir can be classifi ed into two sub-categories based on the pore features by core observation both microscopically and macroscopically, as well as petrophysical experiments, i.e., simple combination type and dissolution enlargement type. Then, the logging response characteristics of two sub-categories of fracture-vuggy type reservoirs are analyzed by using electrical imaging logging and conventional logging data, and the characteristic parameters are extracted, such as peak of porosity spectrum, width of porosity spectrum, deviation of acoustic velocity, fracture porosity and matrix permeability. Finally, the semi-quantitative discrimination chart for classifi cation of reservoir type is established by combining with application examples. The results show that the method of combining electrical imaging logging and conventional logging has good application result in identifying reservoir types. The dissolution enlargement type fracture-vuggy dolomite reservoir of sub-salt is the most developed in Tazhong area, while the simple combination type fracture-vuggy reservoir is dominated in Tabei area. This classifi cation method is of great practicability and generalization.

The construction of gas storage is now the only practical solution in economically developed areas of central and eastern China since the natural gas pipeline and LNG can no longer satisfy the peak demand modulation and supply guarantee. In addition, another two types of targets, depleted gas reservoir and salt cavern in central and eastern China are not suffi cient to construct gas storage. The aquifer target has complex structure and low level of exploration, which is challenging to select favorable site and carry out preliminary evaluation. By analyzing the aquifer conditions for gas storage construction at home and abroad and the characteristics of aquifer target in China, such as great burial depth, complex structure and poor physical properties, evaluation criteria and methods for aquifer sites selection are put forward. As a result, Baiju aquifer structure with relatively good conditions for gas storage construction is selected as the study object in the central and eastern China. The results show that: (1) The maximum fl ow pressure that the aquifer can withstand is 15.0 MPa and the enhanced pressure factor is 1.2; (2) The effective space volume of gas storage is 3864×10⁴m³, gas saturation is 64.7% and total gas storage capacity is 17.5×10⁸m³; (3) There are many uncertain factors in the plugging treatment of the two open hole wells at the top of the aquifer structure, and the risk of gas storage construction is high. It is suggested that the subsalt aquifer with shallow burial depth, good physical properties and large-scale water body in the central and eastern China should be selected for gas storage target.