Qaidam basin can be divided into three exploration provinces – Jurassic coal-type gas on the northern periphery of Qaidam Basin, Paleogene – Neogene oil-type gas in West Qaidam and Quaternary biogenic gas in Sanhu area – according to the characteristics and distribution of source rocks as well as other elements, such as the accumulation pattern and law. The source rock of coal-type gas is characterized as wide distribution, high organic abundance, strong sourcing capability, burial in the late periods, and a large amount of reserves. The key controlling factors of coal type gas accumulations in the basin margin area are ancient structures, transport systems and source trap relations. There are two types of reservoir-cap assemblages including lower assemblages (base rock-Jurassic-Paleogene) on the periphery of the basin and upper assemblages (Neogene) of the late structures within the basin. There are also two accumulation models – accumulations outside the source and accumulations above the source. The recent exploration efforts have been focused on the lower assemblages (base rock-Jurassic-E₁₊₂) in eastern segment in front of Alkin Mountains and the western segment in front of Qilian Mountains as well as the upper assemblages (N₁, N₂¹) in Lenghu and Eboliang structural belts inside the basin. Oil-type gas exploration area is characterized as three depressions, two sets of source rocks and three types of reserves, with a number of laws for gas abundance, such as distribution surrounding the depressions, nearsource accumulation, relay transport and sweet-spot accumulations. It is obvious that accumulations took place in the late periods, with a ^“relay style^” for migration and accumulations. Hydrocarbon source rock is deep in burial, high in maturity and strong in sourcing capability. The zones with a high gas-oil ratio are favorable areas for exploration of oil-type gas, such as the Shizigou-Youshashan-Yingdong structural belt and Youquanzi-Kaitemilike-Youdunzi structural belt. Biogenic gas exploration is characterized as a single kind of source rock, low abundance, and rapid deposition, in the pattern of sustainable sourcing, vertical and lateral migration and dynamic accumulations. The nose uplifts on the northern slope of Sanhu Depression and the peripheral zone of anticline are favorable exploration areas for lithologic gas reservoirs.

Lacustrine carbonate rock is widely developed in the Paleozoic and Meso-Cenozoic continental sedimentary basins in China. Oil and gas exploration has confirmed lacustrine carbonate rock is hydrocarbon source rock and reservoir rock. By the end of 2012, a total of 63 oil and gas fields of lacustrine carbonate rock have been proven in Sichuan Basin, Bohai Bay Basin and Qaidam Basin since the discovery was made in Sichuan Basin in 1956. The proven oil in place reached 5.97×10⁸t. Development and distribution of China^’s onshore lacustrine carbonate rock is controlled by a number of factors, such as structural background, paleo-climate, sedimentary source recharge and marine invasion, with development of two main types of lacustrine carbonate rock – reef and complex lithology. Generally speaking, the petrophysical properties of reservoirs are poor, except for reef reservoirs. They are typical compact oil reservoirs. Reservoirs of lacustrine carbonate rock are often interbedded with hydrocarbon source rock and have good conditions for hydrocarbon accumulations. Hydrocarbon abundance is controlled by sedimentary facies, fracture development and structural location. It is difficult to predict the sweet spot. Compact oil reservoirs mainly composed of lacustrine carbonate rock are extensive distributed in China with a great potential for resources. Assessment indicates that the distributed area exceeds 10×10⁴km² while the amount of geological resources is 57×10⁸t, showing a promising prospect for exploration and development.

Eboliang structural belt on the northern periphery of Qaidam Basin is composed of four surface structures – Eboliang No.Ⅰ, Eboliang No. Ⅱ , Eboliang No. Ⅲ and Hulushan. The latest study and re-investigation of old wells indicate that this belt has good conditions for natural gas accumulations, because it is located in the Jurassic gas sourcing depression with development of large-scale structural traps, high-quality reservoir-cap assemblages and the deep and large faults that connect gas sources. There are two patterns for gas accumulations – within the source and above the source. Significant breakthroughs have been made in the nearby Niudong structure in recent time. Gas show was found in drilling of other structures. In addition, E-7 Well obtained an industrial gas flow. Based the accumulation conditions and analysis of the current exploration conditions, this paper proposes to drill exploration wells first in Eboliang No.Ⅰ structure in this belt while making active preparations for other structures. Meanwhile, the detailed seismic exploration efforts should be focused on Eboliang No. Ⅲ structure to locate the trap for exploration.

Penglai 19-3 Oilfield is the largest oilfield found in China^’s offshore area. Part of crude oil produced in this oilfield is immature and low-mature oil. A large quantity of experimental data about crude and source rock were used to systematically analyze the physical properties, group compositions and biomarker compounds of immature and low-mature oil from Penglai 19-3 Oilfield. The study is made on the sedimentary environment of source rock, characteristics of source rock and organic matter evolution. The results of the study indicate that immature and low-mature crude oil from Panglai 19-3 is characterized with high density, high viscosity, middle sulfur content, low wax content, low saturated hydrocarbon content, low saturation-aromatics ratio, high non-hydrocarbon content and high asphaltenes ratio, low Pr/Ph, low rearrangement sterane abundance and Ts

Geophysical exploration technology is the important method and key technology to acquire information about underground oil and gas. It is the important basis for making decision on oil and gas exploration and development. In recent years, China National Petroleum Corporation has increased investment in geophysical technological research in oil and gas exploration and development in mountain front steep dip structural belt, carbonate rock, oil-enriched sag lithologic formation trap and tight (unconventional) oil and gas areas. The principles and theories of ^“wide line with large array^”, ^“wide azimuth and high density^” and ^“wide azimuth, broadband and high density^” in particular, effectively promoted integration of seismic acquisition, processing and interpretation and achieved good results in production and research projects. This paper reviews the progress of geophysical technology and its application results and looks into the future development trend for geophysical technology, thus providing useful information for the plans, research projects and application of new geophysical technology.

The single sensor high-density seismic technology has been put into wide application thanks to continual improvement of oil and gas exploration and development accuracy. The era for large seismic exploration data of oil and gas industry is coming unexpectedly, thus leading to a series of challenges for field seismic data acquisition, quality control, data processing and information study. The past seismic acquisition management pattern and data processing and interpretation environment are obviously out of date. Focusing on the issues facing oil and natural gas seismic exploration data, this paper proposes a series of technological strategies, such as use of light seismic instruments, quantification of quality control, high-efficiency acquisition of controllable source and further study of data, in cope with the challenges facing large seismic exploration data.

The present-day seismic data acquisition is characterized in massive seismic data, complex wave field and high-density spatial sampling. To design the indoor processing configuration for massive seismic data, improve efficiency of massive data processing and solve the bottlenecks of quality control in massive data processing and inadequacy of conventional process and technology, Research Institute of BGP has developed the method for rapid analysis and quality control under the condition of massive data processing, thus achieving effective compression of large dataset. Based on the current technological level in the related fields, this paper looks into the technological development trends, such as further tapping of data and information in massive data processing and analysis, data visualization and information merger, in the efforts to acquire a variety of information in the future processing large dataset.

With the exploration technological progress continually made in offshore oil seismic exploration field, the requirements on seismic data acquisition geometry have become higher and higher. It is necessary to choose the most appropriate data acquisition geometry. Based on the study of the attributions of the geometry, this paper analyzes and compares the two geometries of PATCH and Orthogonal, which are widely used in submarine cable seismic exploration, in terms of such attributions as azimuth, offset distribution, folds and acquisition footprint, and folds decreasing area. Then it summarizes the advantages and disadvantages of the two geometries in seismic data acquisition. In addition, the practice indicates that analysis of the attributions of geometry can provide the effective method and basis for selection of geometry according to the different geological exploration tasks and environmental conditions.

Usually, the quality of seismic data of Xihu Depression is not quite well. The main reasons result from the characteristics of the seismic geological conditions in this area, such as development of thin sand-shale interbedding, no abrupt change or big bench between velocity and density, and difficult to form strong reflection interface, leading to development of multiples in seismic intervals. It is well-known that seismic multiples suppression is always a bottleneck in geophysics. To solve this bottleneck, VSP forward modeling is used to study the multiples forming mechanism of Xihu Depression in order to identify the main interfaces and horizons of multiples and provide the basis for suppression of multiples in digital processing. The dynamic laws and dynamic characteristics of multiples are studied on the basis of the data from actual drilling in Xihua Depression. Then VSP forward modeling is used to find the main horizons and interfaces of multiples and determine the relative strength of multiples and the types of main multiples affecting effective seismic waves. The research results indicate that all strong reflection interfaces in this area can produce multiples. The multiples that affect the quality of seismic imaging are compound multiples stacked with multiples from the different paths.

Selecting the time window for statistical analysis, this paper summarizes three characteristics of a certain oil company in upgrading its controlled reserves. The upgrading time is usually five years following submission of the reserves. The controlled reserve of a single block exceeding 200×10⁴t is the backbone for upgrading. The petrophysical properties of a reservoir exert an important influence on upgrading of controlled reserve. The conceptions of upgrading coefficient and upgrading ratio are defined to systematically evaluate upgrading potential and capability of controlled reserve. The related parameters are also established for evaluation. Based on the company’s current accumulated controlled oil reserve, this paper evaluates upgrading and predicts the proven oil reserve growth trend. With respect to the fact that the block is in its middle and late exploration and development stage with a limited reserve, the Gompertz model and Hubbert model are used to predict the future reserve growth trend and the future quantity of reserves. It is confirmed that the error is less than 7 percent. The above-mentioned two methods make clear the trend for the company^’s newly-additional proven reserve and the quantity of additional reserves in the next five years, providing a reliable basis for formulation of exploration and development strategy. It has great significance to put them into wide application.

Pre-Caspian Basin is one of the richest oil and gas basins in the world. Based on the thick salt formation of Lower Permian Kungurian, the entire section is divided into upper-salt strata and lower-salt strata. Block S is the main exploration target in the upper-salt strata. This block has experienced four exploration stages – evaluation, summarization, breakthrough and progressive and enlarged exploration – since it was acquired in 2004. The exploration effort was focused on inter-salt and salt canopy structural traps in the initial stage. Then the effort aimed at searching of producing reserves, such as ^“salt eaves^” trap, lithologic trap and salt canopy low-amplitude structural trap. The geological reserve is increased to 9050×10⁴t at the present time from 800×10⁴t at the purchase time. The analysis indicates that the success in exploration of Block S is based on the following aspects: analysis of old data served as the basis for making breakthrough in exploration of a new block and the proposed new conception of ^“salt eaves^” holding the key to exploration success. The evaluation method for finding clues to locate salt window, searching channels to locate the position, finding the buried depth to determine strata series and searching traps to determine positions of well is the cornerstone for high-efficiency exploration.

Tectonic evolution of North Atlantic can be divided into three stages – the Permian intracontinental rift stage, the Triassic-Jurassic syn-rift and thermal subsidence stage and the Cretaceous passive continental margin stage. The passive continental margin stage includes two evolution branches. The ^“western branch^” represents Baffin Basin and West Greenland Basin formed from separation between Greenland plate and North America plate while the ^“eastern branch^” includes Faro Basin, Norwegian Shelf Basin and East Greenland Basin formed from separation between Greenland Polar plate and European plate. The Late Jurassic – Early Cretaceous period is the important hydrocarbon sourcing stage for the North Atlantic sedimentary basin with three types of source rock developed – restricted marine source rock of the transition period, restricted marine source rock of the rift stage and open marine source rock of the passive continental margin stage, of which restricted marine source rock is the most abundant in organic matter and highest in hydrocarbon sourcing ability. Based on development characteristics of source rock, horizontal distribution and exploration degree of the basins, it is pointed out that Norwegian Shelf Basin and Faro Basin have great potential for exploration while East Greenland Basin shows a large-scale prospective reserve.