Great success has been achieved for the exploration and development of marine shale oil in North America, revealing the significant value of industrial shale oil exploration and development. When shale oil exploration is practically carried out in the Jiyang depression which is the typical representative of continental faulted basin in eastern China, a series of technologies are adopted. It is revealed by the comprehensive source rock evaluation technology that the hydrocarbon generation in mud shale of saline lake is characterized by early hydrocarbon generation and high hydrocarbon-generating transformation ratio. It is confirmed by the mud shale micropore structure characterization technology that laminated lithofacies has the reservoir properties of high porosity, large pore diameter and good connectivity. And by virtue of the quantitative free oil evaluating technology, the differential enrichment mode of free oil in favorable lithofacies of mud shale in different sedimentary environments in the Jiyang depression is established. The shale oil in the Jiyang depression is compared with that in North America. It is indicated that in the Jiyang depression, the development of favorable lithofacies is the base of shale oil enrichment, appropriate evolution degree is the condition of shale oil enrichment, sufficient free composition is the key to shale oil enrichment, and good crushability is the guarantee of effective development. And finally, the shale oil zone selection and evaluation criterion suitable for the saline lake deposit within continental faulted depression in eastern China is prepared.

Although the remaining resources are still abundant in oil-rich sags such as the Raoyang sag in the Jizhong depression, it is increasingly difficult to discover more sizable reserves in these highly explored sags. To carry out re-exploration and make significant breakthroughs, it is necessary to construct a high-quality 3D seismic data platform over the entire sag. Such a platform would be helpful to investigations of overall structural framework and depositional systems, seismic reservoir prediction and fine delineation of exploration prospects. This paper proposes a new idea of re-exploration that includes optimization of seismic survey plan and acquisition parameters, obstacle avoidance over urban areas, merged processing and target fusion, and then constructs the seismic data platform for the whole Jizhong depression covering an area of 10000 km², which would play a key role for making breakthrough and discovery of more sizable reserves during re-exploration of the oil-rich sags. The proposed idea and practice can also provide references for oil and gas exploration in other similar regions.

Considering the great success in the shale gas exploration and development in the Sichuan Basin, the shale gas potential in the southern Junggar Basin is worthy of study. Accordingly, based on the surface geologic investigation and the drilling results of shale gas detection wells, analysis and comparison were carried out for the organic geochemistry characteristics of the Lucaogou Formation shale in the eastern and western parts of the Bogda Mountain, the upper, middle and lower members of the Lucaogou Formation, and outcrop and drilling samples. Moreover, the unconventional hydrocarbon potential in the Lucaogou Formation was predicted. Some conclusions are drawn as follows. First, in the Lucaogou Formation, the kerogen types discriminated with rock pyrolysis are more reasonable than those discriminated with microscopic examination, indicating primary type I and type Ⅱ₁ kerogen, a little type Ⅱ₂ and type Ⅲ, and more type Ⅲ in the eastern part than the western part of the Bogda Mountain. Second, the Lucaogou Formation has high organic matter abundance. Particularly, 77% of the samples show TOC ≥ 2%, mostly between 3.0% and 4.0%. Horizontally, the TOC is higher in the western part than that in the eastern part of the Bogda Mountain; vertically, it is higher in the middle member than that in the upper member, but higher in the upper member than that in the lower member of the Lucaogou Formation. Third, the peak Ro is mainly around 0.8%, the T_max ranges from 440℃ to 450℃, and the organic matter is mainly in mature stage. The Lucaogou Formation was uplifted and exposed earlier in the eastern part than the western part of the Bogda Mountain, and accordingly the thermal evolution in the eastern part is slightly lower than that in the western part. Fourth, the Lucaogou Formation is highly potential for tight oil and shale gas exploration, and the shale gas potential in the western part is better than that in the eastern part of the Bogda Mountain.

The Permian Lucaogou Formation in the Junggar Basin contains typical tight reservoir with low porosity, where natural fractures are of great importance for improving the seepage structure. Based on analysis of outcrops, cores, casting thin sections and scanning electron microscope (SEM), three types of natural fractures were identified in the Lucaogou Formation tight reservoir, including structural fractures, diagenetic fractures and abnormally high-pressure fractures. The structural fractures include shear fractures and expansion fractures, which are usually high-dipped and were developed during several stages of tectonic movements in the Junggar Basin. The diagenetic fractures consist of bedding, intragranular and intergranular fractures, of which the bedding fractures might be formed during tectonic action and hydrocarbon generation, while the intragranular and intergranular fractures are related to dissolution. The abnormally high-pressure fractures, mainly drainage fractures, are the products of extremely high fluid pressure which induced one principal stress to convert into tensile stress and produced fracture clusters in bent orientation and with different openings. Imaging logging statistics of 13 wells drilled into the upper "sweet spot" and 8 wells drilled into the lower "sweet spot" reveal less structural fractures-generally less than 0.5 fractures/m, and well-developed bedding fractures-generally more than 2 fracture/m. Core observation further confirms that the bedding fractures are primary in the Lucaogou Formaion tight reservoir, accounting for over 70%. Primary factors controlling the development of natural fractures in the Lucaogou Formation tight reservoir are sedimentary microfacies, lithology, heterogeneity, layer thickness, TOC and tectonic action.

Micro-pore structure is an important factor controlling the preservation properties and development results of unconventional gas reservoir. In this paper, the micro-pore structure of the Xu 5 reservoir in the western Sichuan depression was studied using SEM (scanning electron microscopy), low-temperature nitrogen adsorption, laser scanning confocal microscopy and micro-nano CT scanning techniques. The following results were obtained. First, the pore space in the Xu 5 sandstone reservoir is composed of solution pores, intercrystal pores and micro fractures, with the solution pores in dominance, and the pore space in the shale reservoir is composed of mineral matrix pores (e.g. intergranular, intragranular and intercrystal pores), organic pores, and micro fractures, of which the most developed types are intergranular and intercrystal pores. Second, the pore structure of the Xu 5 reservoir is complex, primarily consisting of mesopores and macropores which show in the shapes of wide body and narrow neck, and flat and narrow seam, with a specific surface area between 1.44 m²/g and 11.7 m²/g, and an average pore diameter ranging from 5.75 nm to 15.6 nm; the specific surface area of the sandstone is smaller than that of the mudstone, but the pore size of the sandstone is larger. Third, since the unconventional gas reservoir is very complex, single technique may only provide incomplete results, and several modern high-precision techniques can be combined together for characterizing the micro-pore structure. On this basis, the factors that control the micro-pore structure and the relationship between the production and pore types in the Xu 5 unconventional gas reservoir were analyzed, in order to provide the geological base for subsequent "sweet spot" prediction.

Based on seismic, drilling and chemical analysis data, and studies on basin development background and structural and depositional characteristics, the source rock and resource potential in the Paleogene Kongdian Formation and the fourth member of the Shahejie Formation (Sha 4 Member) in the Baoding sag, the Jizhong depression, were analyzed synthetically using logging evaluation and basin simulation techniques, and the prospect and favorable targets of oil and gas exploration were predicted. The study shows that the Baoding sag is a dustpanlike faulted depression which is faulted on the west and overlaid on the east, under the control of the fault belt on the east of the Taihang Mountain, and it has similar basin-forming background and tectonic-sedimentary evolution process as the sags on the west of the Jizhong depression, such as the Langgu sag, the Xushui sag and the Shijiazhuang sag. During the deposition of the Paleogene Kongdian Formation and Sha 4 Member, the northern part of the Baoding sag connected to the Dianbei subsag of the Baxian sag and the Xushui sag in the same confluence lake basin, where two sets of brackish semi-deep and deep lacustrine source rocks were developed, i.e. the fourth member of the Shahejie Formation-the first member of the Kongdian Formation (Sha 4-Kong 1), and the second member of the Kongdian Formation-the third member of the Kongdian Formation (Kong 2-Kong 3). The distribution area of high quality source rocks with TOC of more than 2% is 1470 km² and 910 km², respectively, and the thickness is 10-140 m in the subsags. The estimated oil resources and gas resources are (1.27-2.03)×10⁸t and (270.24-333.29)×10⁸m³ respectively in the Baoding sag, which mainly accumulate in the buried hill and the Kongdian Formation. The sag has good prospect of oil and gas exploration. In the sag, the drape anticline in the "uplift-in-sag" Qingyuan buried hill provides good accumulation conditions, which can develop into buried hill reservoirs with "new source rocks and old reservoir beds" and structural reservoirs in Kong 1 Member as favorable exploration breakthrough points.

Gas adsorption capacity of shale is a key parameter of gas potential evaluation and resource potential prediction. The marine shale of Silurian Longmaxi Formation in the Baojing area is high in thermal evolution degree, and its gas adsorption capacity is unclear and will be a focus to be figured out. In this paper, 12 core samples of Longmaxi Formation shale in Well BY-1 in the study area were collected and tested in terms of total organic carbon (TOC), thermal maturity (R_o), X-ray diffraction, field emission scanning electron microscopy (FESEM), low-pressure liquid nitrogen adsorption and high-pressure isothermal methane adsorption. The results show that the marine shale in the study area is high in organic abundance and thermal maturity with TOC and Ro in the range of 0.57%-2.16% and 2.86%-3.76%, respectively. The mineral composition includes quartz (33.7%-73.9%), plagioclase (0.7%-16.9%), and clay mineral (15.8%-54.4%). Nano-scale pores are developed in shale dominantly in the forms of intergranular pore and organic pore. According to the low-pressure liquid nitrogen adsorption test, the pore diameter of shale is in a large range and mesopores (2-50 nm) are dominant. The high-pressure isothermal methane adsorption test revels that the gas adsorption capacity of Longmaxi Formation shale in the Baojing area is high-0.82-3.56 m³/t, averaging 1.93 m³/t. The gas adsorption capacity is mainly controlled by the organic abundance and the specific areas of mesopores and micropores. The organic matter in the Longmaxi Formation shale is of high maturity. With the thermal evolution of organic matter, abundant micropores and mesopores are generated and their specific area is large, providing large space for shale gas adsorption, resulting in high gas adsorption capacity of shale.

The Tanchou block covers a large-scale salt swell developed within a salt-lake basin, where the structure is very complicated. In recent years, further investigation has been carried out into the structure and evolution in the Tankou block, revealing that this block is an S-shaped embedded structure with the characteristics of salt lake. Based on drilling data and oil and gas discoveries, it is pointed out for the first time that multi-stage slope-break fans are developed in the downthrow side of the syndepostional fault belt in the Tankou bulge, and there are four types of key exploration targets which are 1) structural reservoirs in the margin of the Tankou bulge, 2) beach bar lithologic reservoirs and underwater distributary channel structural-lithologic reservoirs in the eastern and western parts of the Tankou bulge, 3) slopebreak lithologic reservoirs and embedded structural reservoirs in the downthrow side of the syndepostional fault belt in the southern part of the Tankou bulge, and 4) the Xingouzui Formation in the high step-fault zone and the Cretaceous separate-source reservoirs.

The Devonian shale widely distributed in northwestern Central Guangxi depression is the primary target for seeking breakthrough of shale gas in the Yunnan-Guizhou-Guangxi region. In order to identify the accumulation conditions and potentials of shale gas in this region, more than 300 core samples were evenly taken (at sampling interval of 2 m) in Well GY 1 for organic geochemistry and rock mineralogy analysis. Well GY 1 is the first exploration well drilled through all Devonian shale gas formations in the Central Guangxi depression. The analysis results indicate that the Devonian shale is characterized by big thickness (470-1300 m), high TOC (0.23%-10.63%) and high maturity (R_o=1.88%-2.83%), which are favorable for the generation and accumulation of shale gas. Moreover, the shale has high content of brittle minerals and presence of organic pores and micro-fractures, implying the high probability of the shale gas reservoir to be stimulated. However, faulting activities during multi-stage tectonic movements damaged the shale reservoir, especially the gas-bearing potential. In view of exploration potentials, analysis of three sets of major shale gas formations (Liujiang Formation, Luofu Formation and Nabiao Formation) indicates that the Lower Liujiang Formation is the primary shale gas exploration target for its relatively favorable organic geochemical and physical properties and hydrocarbon accumulation conditions.

In this paper, detailed analysis was made on 3 oil samples from Well X-1 and 14 cutting samples from Wells X-1 and M-1 in the Haute Mer A Block, the Lower Congo Basin. The results show that the composite biomarker characteristics of oil produced from Well X-1 are obviously different from that of typical lacustrine source rocks in the South Atlantic. The crude oil (1982.1-1989.2 m) of Well X-1 presents the characteristics of marine source rocks with low Pr/Ph (0.97), Pr/nC₁₇ of 0.85, Ph/nC₁₈ of 0.96, C₂₆/C₂₅ tricyclic terpane less than 1.0 and low C₃₀ tetracyclic polyisoprene paraffin hydrocarbon/C₂₇ diasteranes (0.55). Its oleanane abundance is high, indicating that the oil was originated from the source rocks of Upper Cretaceous or above. Oil-source correlation indicates that the oil is genetically related to the source rocks of Upper Cretaceous-Eocene Madingo Formation. The basin modeling further proves that the Miocene Paloukou Formation source rocks are locally matured with limited hydrocarbon supplying capacity, while the Madingo Formation source rocks are currently during the peak stage of hydrocarbon generation and expulsion. The depocenter is during high-over mature stage. Well X-1 is close to the hydrocarbon generating sag of Madingo Formation, where conditions are favorable for oil and gas accumulation. Therefore, it is inferred that the source rocks of Madingo Formation serve as the major contributor to the oil of Well X-1.

To understand the distribution characteristics of less-explored granite buried hill reservoirs, based on the geological models and the effective grey energy to delineate weathering crust of granites, this paper describes the scope and thickness and analyzes the influences of tectonic activities, weathering leaching and paleogeothermal changes on the accumulation model and distribution of high quality granite reservoirs in the western segment of the Shaleitian bulge, the Bohai Sea. Finally, this paper proposes a reservoir prediction method combining geological genesis with geophysics. Application of this method in the study area shows that:1) high content of brittle minerals, such as feldspar, in the granite buried hill, provides the foundation for the development of high quality reservoir; 2) the displacement of fault walls induced the development of induced fractures, the tensile force of folded ridges promoted the development of high-dip fractures, and the temperature and pressure changes caused by structural uplifting controlled the development of nearly horizontal fractures; and 3) in the southwest margin of the study area, superposition of fractures of three types brought extremely developed fractures, and this zone evolved into good granite reservoir zone after weathering leaching for a long time. The prediction results are consistent with the actual geological conditions revealed by field drilling data, indicating that the geological genesis-geophysics method can effectively predict the distribution of high quality reservoirs in the study area. This provides a reference for prediction of high quality reservoirs in granite buried hills in less explored area.

There are two sets of thick basalts covering large areas within M Block, Iceland. Due to their strong shielding effect, the seismic acquisition in this block is rather difficult. The signal-to-noise ratio of previously acquired data is overall low with no reflected signal acquired from the underlying strata. To acquire efficient seismic data in this block, especially that of the middle and deep strata underlying the basalts, the inclined-cable acquisition mode subject to the geological targets was designed after the analysis of acquisition difficulties, key parameter demonstration and technical study. While guaranteeing the acquisition frequency width, this mode can combine with low-frequency largecapacity seismic source to improve the penetration capacity of seismic signals, thereby facilitating the acquisition of high-quality seismic data. A set of seismic acquisition technology for the geological targets under the shield of basalt is ultimately developed.