Ordovician reef beach of Tarim Basin, whicn belongs to Yijianfang and Lianglitark Formations, is mainly distributed in Tazhong, Bachu, and Lunnan areas. The lithologic characteristics are mainly binestone, bafflestone, and framestone. Yijianfang Formation features in small scale of biologic reef and its reef communities are mainly pallet spongy and alga. While Lianglitark Formation features in large scale of biologic reef and the reef communities are mainly coral stromatoporoid reefs and calcareous alga. It is the first reef ever discovered in coral-stromatopora in China. Large reef beach developed in Tazhong I slope break zone, consisting of framestone, binestone, calcirudite, and limearenite. Vertically multi-cycle knoll reefs, lime mud mound, and grain banks developed into reef flat,which is extremely thick and the highest thickness reaches more than 300meters. Geomorphologically it shows hummocky salient. Horizontally the complex is widely distributed along the slope break belt, of which the main body is located in TZ24 and TZ82 wells and it is almost 220 kilometers long from east to west. Reef beach also developed in high-quality vuggy reservoirs, as well as dissolution pores, residual intergranular pres, fissure and skeleton pore space are the main space for oil and gas accumulation. Multi-phase reef flats are vertically superposed and horizontally integrated. Tarim Basin features in well developed carbonatite slope break belt and large area favorable for exploration. Giant reef-beach oil and gas fields have been discovered in Tazhong area. Such zones as the eastern Lungu and southern Yingmaili slopes, and the Manxi slope break belt are the important areas for discoveries of reef-beach oil and gas fields.

Late Triassic of Ordos Basin is the lake-basin sedimentary evolution period of Craton Interior Depression. It features in stable structural activities and well-developed peripheral drainage network system. It has favorable oil generating conditions and hydrocarbon generation conditions and has deposited a great number of bearing systems, including large deltas and submarine fans. Based on the research on drilling data combined with seismic sequence stratigraphy, this paper classifies the Upper Triassic Series (Yanchang Formation) as a complete secondary series of strata. By taking sedimentary cycles and three lake-flooding periods as the principle, it divides it into four tertiary series of strata, each of which is further divided into various system tracts. Based on this, it analyzes the features of source-reservoir-cap rock assemblages and the conditions for hydrocarbon accumulation in lithologic strata, putting forward some suggestions on making full use of seismic data, conducting sequence stratigraphic research and comprehensive evaluation of litho-stratigraphic traps.

Deeply buried source rocks in Qingshui Subsag of Liaohe Depression feature in well development, huge thickness, wide distribution, high abundance and good types of organic matter. Es3 source rock is mainly lacustrine mudstone and has favorable conditions for oil generation, laying a solid basis for forming large-and medium-sized lithologic oil and gas reservoirs. Reservoir sandstones developed in Dongying Formation and they are mainly floodplain fluvial deposits. Channel sandbodies developed in Ed3 with largermonolayer thickness and good reservoiring performance, providing favorable conditions of the development of lithologic oil and gas reservoirs. Favorable regional caps developed in each segment of Dongying Formation, forming good reservoir-cap assemblages combined with sandstone rocks developed in each segment in the area. Two types of oil and gas transportation systems developed in the Formation, i.e., the fault transportation system determined by structural effect and the sandstone transportation system determined by sedimentary effect, providing channels for oil and gas migration and accumulation. Research shows that the lithologic reservoir of Qingshui Subsag could be the target for next exploration.

Deep or semi-deep lacustrine oil shale is widely distributed in the Permian Lucaogou Formation in Fukang area on southern margin of Junggar Basin. Fukang research area of oil shale is located at the structural transition area between paleo-syneclise and Late Paleozoic Bogda faulted depression trough. Permian oil shale crops out due to large-scale reversed slip faults. Commercial types of ore bodies are organic sedimentary bedded deposits. Oil shale strata can be divided into four segments from old ones to new ones, as well as high-quality oil shale concentrates in the second and third ones. Trace elements analysis based on different indicators shows that most oil shale samples are categorized as land facies judged by the ratio of Sr/Ba. Baron content shows that oil shalemainly exists in freshwater sedimentary environment but with sea water effect occasionally. Fukang oil shale has extremely high value for production

Natural gas hydrate is a new alternative energy which is clean and high efficient. Baiyun Sag has favorable water depth, thermobaric and basic geological conditions for the accumulation of natural gas hydrate. Two sets of main sources rocks developed in the sag, i.e., Wenchang Formation and Enping Formation, of which TOC and Ro contents are high. The source rocks are gas-prone and have great potential of hydrocarbon generation, providing sufficient gas for hydrate accumulation. What's more, the sag has excellent migration conditions for hydrate accumulation. There are two types of migration pathways: the first one is faults connecting gas resources; the second one is diapirs. There are three kinds of migration patterns, i.e., singlefault migration, single-diapir migration, and diapir-before-fault migration. Gas hydrates are predicted in the sag for the first time and they are divided into two groups: hydrate deposits with BSR and hydrate deposits without BSR. Both single BSR hydrate deposits and double BSR hydrate deposits are discovered in the sag. Hydrate thickness of the sag is predicted to be ranging from 30m to 100m. Optimistically speaking, the hydrate resources is predicted to reach 60.4 trillion cubic meters, while it is conservatively predicted to be about 8.7 trillion cubic meters in the sag. It is shown that Baiyun Sag has broad prospect for exploration for natural gas hydrate

Deepwater area has currently become one of the most popular domains of exploration for oil and gas for its abundant oil and gas resources. The production of deepwater oil and gas and its proportion in offshore oil and gas rises continually. For example, the production of deepwater oil and gas increased to 1.4 billion barrels in 2005 rising from less than 0.2 billion barrels in 1996. It accounted for 10% and 7% in offshore oil and gas production in 2004, which will rise to 25% and 12% in 2005. Deepwater exploration is currently the most successful and most profitable domain. However, along with the development of deepwater exploration, it will face up much more difficulties, such as smaller size of reservoir, more complicated reservoir fluid, worse marine operation, and higher requirement for techniques. To solve these problems, many advanced technologies are widely applied, including high-resolution 3D seismic technology, 4C/4D seismic technology, drilling technology of horizontal wells and extended reach wells, intellectual completion technology, various types of deepwater operating platforms, and more autonomous submarine production systems. The deep area is the extension of shallow water area in China, so it has some oil and gas geological conditions similar to the shallow water area. Deepwater area in China has favorable conditions for oil and gas accumulation and broad prospect for oil and gas exploration, which has been proved by the up-to-date discovery made in Lizhiwan3-1-1. Therefore, it is urgent to accelerate exploration and development in deepwater area and make full use of the rich oil and resources there.

According to conventional seismic exploration technology, analog signals exported from analog geophones are imported into digital seismograph acquisition units or key stations for analog-digital conversion, data arrangement, and storage, and then are reprocessed in data processing centers. However, based on full-digital seismic exploration technology, the digital geophone system is employed, as well as digital signals exported from digital geophones are digitally transmitted into key stations for arrangement and storage. At last, the digital signals are processed by using the technology of digital combination and superposition and reprocessed in data processing centers. As compared to the conventional technology, the new one improves the capability for resisting electromagnetic interference in transmitting signals, enhances the instantaneous dynamic range of signals, broadens frequency bands of signals, and is favorable for improving the signal-noise ratio and resolution of seismic data. PetroChina has so far cumulatively acquired 6,485 kilometers of 2D full-digital seismic data and 936 square kilometers of 3D full-digital seismic data, of which the quality is obviously improved.

It is difficult to acquire complete data in field and enhance the signal-to-noise (S/N) ratio of data in zones where urban area is large, nearsurface conditions are complicated, main target layers are shallowly buried, S/N ratio of seismic data is low, obstacles are widely distributed, and the population are highly concentrated. Good results have been achieved in exploration, based on the design of special geometry, the selection of routes and points aided by high-precision aerophotos, the combined excitation of explosive source and vibroseis, and the embedment of geophones by using electric drill first. This fills the blank that there are no seismic data acquired in complicated city zones and meets the requirements of oilfield companies for conducting integrated research and increasing reserves and production. Practice shows that the approach is scientific and rational, and easy to operation, providing a good reference for seismic exploration in city zones with extra-shallow target layers

Restoring the exact thickness of eroded strata is critical to reconstruct the histories of initial sedimentary-structural evolution, thermal evolutions, hydrocarbon generation, expulsion, migration and accumulation, and also to quantitatively evaluate the potential of oil and gas resources. On the basis of the scientific definition of eroded thickness and the analysis of factors that affect eroded strata thickness, a new category scheme on eroded strata thickness restoration in sedimentary basins is proposed, which classifies all currently used methods into five types as geological comparison, geothermal parameters, well logging technology, sedimentary rate and the others. Four commonmethods are also discussed to analyze the basic principle, advantages and disadvantages, and applicability of the new method. It is considered that the eroded strata thickness should be restored quantitatively and synthetically by using proper method combined with other approaches based on the understanding of regional geological backgrounds and characteristic of other methods.

Headspace gas technology can be used to analyze physically absorbed and dissolved light hydrocarbons whose composition and content can directly reflect oil and gas information of the underlying strata. When used to surface geochemical exploration, it can predict and judge the position and properties of the transverse profile of the oil-gas zone. It can accurately predict and judge the position and properties of the longitudinal profile when employed to borehole geochemical exploration.

Oil and gas are nonrenewable resources. As an organization, an oil company may accomplish sustainable development by transforming itself into energy enterprise. This paper discusses three stages oil companies may undergo to accomplish sustainable development: the traditional energy production structure stage dominated by oil; the adjustment stage of energy production structure in which oil and gas are laid equal stress and gas develops rapidly; the transformation stage in which the proportion of oil and gas decreases while utilization of new and renewable energy soars. It is pointed out that the adjustment stage is the key for enterprises to realize sustainable development. Currently Chinese oil companies are experiencing the adjustment, as well as natural gas is the most critical supersede energy in the stage. To maintain sustainable development, it is necessary to develop natural gas and unconventional oil and gas resources, and actively exploit international markets in a short term. The long-term objective is to develop new and renewable energy, especially fuel ethanol, wind energy, and solar energy. This provides a solid basis for the transformation of energy structure, the accomplishment of sustainable development by transforming oil companies into energy enterprises.

Oil and gas exploration and development is systematic project that closely connects upstream, middle-stream, and downstream. Combined with the restriction and stages of exploring and developing oil and gas resources and the limits of petroleum geological understandings, this paper discusses the problems existing in China's capability in creating new petroleum geological theories. Based on adjusting the mechanism of oil and gas exploration, development, production, and research, it attempts to eliminate boundaries between petroleum geological research areas, call on all oil and gas fields to take the responsibility of conducting basic petroleum geological research, and created comfortable working environment for all qualified personnel, aiming at promoting the coordination between exploration and development, constructing an innovation system for oil companies? production and research suitable for Chinese specific conditions, exploring new approaches to effectively conduct research on new petroleum geological theories, and establishing an integrative operation mechanism proper to the development of China's oil and gas exploration and development

Marib-Shabwah Basin is a passive rift basin. It was resulted from the extensional tectonics of shear stress field. It is different from active rift basins formed by the uplift of mantle convection. The Mesozoic Era of the basin underwent two phases of rift, i.e., firstly strong and then weak. There are two sets of source rocks. Lam-Meem Formation generated in the first rift phase is the major source bed in the basin. Six hydrocarbon accumulation assemblages developed in the basin. The assemblage of Lam sandstone and Alif sandstone and the assemblage of Alif sandstone and Sabatayn regional cap rock formed the chief oil-bearing beds. The main traps include titled antithetic normal faults, drape traps, and salt structures. Research shows that Marib-Shabwah Basin has favorable hydrocarbon accumulation conditions and broad prospect for exploration

It is considered that the Chepaizi Uplift and the beltlike denudation area from Luliang to Mosuowan should be excluded from Chepaizi- Mosuowan Uplift. The main body of Chepaize-Mosuowan Paleo-uplift is situated in sags and slope area. Structural diagrams of uplift can not be drawn out only based on seismic data so far. All data used for proving the shape of anticline structure are all acquired from the profile west of Maqiao salient. They are the same as the structural characteristics of Maqiao salient while they are different from that of Chepaize-Mosuowan Paleo-uplift. So they can not be used as the representative of the Paleo-uplift. It is inaccurate to conduct research on Paleo-structure on the basis of compressed seismic profiles that have not been used for time-depth conversion. Paleo-erosion area has nothing to do with the structure-uplift effect, because batholithite rock beds with large area of gentle slope are denuded by arc shaped erosion base level next to the edge of interior basins. Denudation area does not reflect uplift structure and cannot determine oil and gas distribution. Oil and gas can only be captured in the updip pinch-out part of the closed discordance formation in denudation area, which has broad prospect.