The dual structure of the complex fault depression in Songliao Basin and its geologic historic construction determined the existence of two sets of petroleum systems and their differences. The deep fault-depression group developed during Late Jurrasic to Early Cretaceous and the particularity of the constructions of its inside sedimentary rock and volcanic rock determined the particularity of the natural gas enrichment conditions. The large thick limnetic facies in Shahezi Formation provided abundant organics for the formation of coal gas. The large-scale volcanic activities during fault-depression period and the strong geothermal field resulted from the huge thick and stable sediment during depression period sped up the transformation of hydrocarbon source rock and resulted in the formation of large amount of abiogenetic gas. The volcanic eruption within several ten thousands square kilometers during the age of Yingcheng Formation led to the formation of the favorable facies belt with the stacked explosive facies and effusive facies, and the medium-acidic volcanic reservoir with pores and fractures developed. The relative independent volcanic rock resulted in the formation of the special trap type under the huge thick seal formation. The early-formed structure provided the trapping conditions for the formation of the primary gas pool. The late structural movement destroyed the primary gas pool, and the secondary gas pool developed. Meanwhile, the deep large fault was connected with the deep inorganic gas sources, as a result, the special CO2 gas reservoir was formed.

In the past 10 years, through innovative ideas, theoretical innovation and technological innovation, important discoveries and breakthroughs have been made continuously in oil and gas exploration in Jilin exploration area. Seven 100-million-tonnage oil-rich regions and two 100-billion-tonnage gas succeeding fields have been so far discovered. Steady growth of large-scale reserves has been realized for eight consecutive years. The laws of oil and gas geology and discovery in the area are summarized. And exploration potential for oil in mid-shallow layers and for gas in deep layers in southern Songliao Basin, for oil and gas in Yitong Basin, and in Yalujiang basins are analyzed. The exploration tendency in Jilin exploration area in the next 10 years is proposed. The growth of large-scale oil and gas reserves during the 12th and 13th Five- Year Plan periods will further boost the steady and rapid development of Jilin Oilfield.

Regional geological features of Jilin peripheral basins are analyzed, it is inferred that the development and evolution of the peripheral basins are controlled by regional structural movement. Multiple peripheral basins have become multi-type superimposed basins after experiencing Paleozoic marine deposition and Meso-Cenozoic continental deposition. The basic petroleum geological conditions of peripheral basins are analyzed systematically. Two big oil and gas exploration fields are found in the basins, i.e. the Paleozoic marine carbonate exploration field and theMeso-Cenozoic continental exploration field, both of which have broad prospect for exploration. It is clear that bothmarine and continental exploration, both Paleozoic and Meso-Cenozoic exploration should be laid the same emphasis.

The Fuyu Oilfield, the first oilfield discovered in Fuxin Uplift, has been developed for 50 years, and the exploration degree is relatively higher. In recent years, more and more exploration results are obtained, with the analysis of reservoir-forming conditions of lithologic reservoirs and the application of reservoir lithology identification and modification technologies in the region. Paleouplifts developed in the Fuxin uplift zone, and "crescent-shaped" fluvial sand bodies are overlaid by a large scale, and "oilrich sags" are distributed in the surrounding areas of the paleouplifts. So the Fuxin uplift zone has favorable conditions for the formation of super large lithology reservoirs. New oil reservoirs are discovered increasingly in the surrounding areas of the old oilfields of Fuyu and Xinli, based on the full application of the 3-D seismic reservoir prediction technology and the sedimentary microfacies technology aswell as the large-scale fracturing and horizontal well technology. New layers including the Yangdachengzi layer are revealed gradually below the Fuyu Oilfield, with reserves exceeding 100 million tons.

The CO2 reservoir-forming periods in Changling fault depression of southern Songliao Basin is analyzed, by fully using the lithofacies characteristics, characteristics of homogenization temperature, gas composition and carbon isotope characteristics of inclusions. The temperature of the inclusions of the CO2 reservoir in the fault depression ranges from 160℃ to 170℃, higher than the palaeogeothermal of the area, which is inferred to be caused by heat events. Through the analysis of the tectonic environment of the basin, it is considered that the CO2 reservoirs in Changling fault depression mainly developed from late Mesozoic to Cenozoic, which should be late reservoir formation

According to the geological data, the formation process of heavy oil in Taobao area is studied, by using geochemical techniques. It is considered that the crude oil of the area began from the Qingshankou Formation of the central sag in the east, migrated for about 50 kilometers and was hindered by the Taobao adverse fault and at last was accumulated in the area. Because of long distance migration, the bed absorbing process and filtration of the reservoir leads to the low freezing point and low asphaltene of crude oil. Meanwhile, the crude oil gets heavy and dense and of high resin, due to oxidation, water washing and biodegradation of formation water. Thus the crude oil has certain characteristics of heavy oil.

According to the statistics of 29 oil and gas fields, the OIIP with low resistivity reservoir features reaches 170 million tons, which accounts for about 20% of the total of Jilin Oilfield. Using a wide range of experimental analysis data and combined with the comprehensive analysis of petroleum geological characteristics such as the sedimentary setting and the tectonic setting, low resistivity reservoirs of Jilin Oilfield were formed due to resistivity drop caused by the conductive network developed from the highly irreducible water saturation, the cation extra conductibility because of the high mineral content of adsorbing clay, the ionic conductivity caused by high water salinity and the complex pore system of heterogeneous reservoirs, In addition, the major factors controlling the formation of low resistivity reservoirs in all oilfields are pointed out clearly, providing scientific basis for the exploration and development of low resistivity reservoirs in Jilin Oilfield.

Based on the current exploration results, the gas accumulation conditions of clastic rocks in Denglouku Formation in southern Songliao Basin are discussed from the perspectives of source rocks, reservoirs, cap rocks, transporting conditions, and accumulation periods of time. In addition to superior source-reservoir-cap conditions, unrestricted carrying paths, and late accumulation period, the deep clastic rocks have other conditions favorable for gas accumulation and as a result have broad prospect for exploration. The gas migration and accumulation is controlled by the distribution of source rock in Shahezi Formation, the distribution of inherited fundamental faults, the physical property of reservoir bed, favorable microfacise and the effective matching of reservoir formation conditions to the time-limit of hydrocarbon supplying. To summarize, there are three accumulation modes, that is, "multiple source, compound migration, physical property controlling reservoir formation", "single source, erect migration, structure controlling reservoir formation" and "single source, lateral migration, unconformity controlling reservoir formation".

High-resolution 3-D seismic data are used to describe the distribution of volcanic rocks and the stages of volcanic eruptions of Changling fault depression in southern Songliao Basin, the structural characteristics of volcanic rocks in the top and the trap types of volcanic gas reservoirs are ascertained. The element capture service (ECS) logging technology and the formation microresistivity image (FMI) imaging technology are used to recognize and calibrate the lithology of volcanic rocks, and the development degree of reservoir cracks is evaluated qualitatively and quantitatively. A lot of data including MDT, NMR (nuclear magnetic resonance) measurement points, cross-dipole acoustic image are used to identify the fluid nature, describe the distribution law of fluids, and determine the gas-water interface of gas reservoirs. Effective porosity is obtained by combining NMR logging with density logging. Gas saturation is got by transforming the capillary pressure using NMR T2 Spectra. The proved reserves of volcanic gas reservoirs in Changling No.1 gas field are calculated based on all the above efforts

Luxiang fault depression is a first-order tectonic unit of Yitong Basin. The strata in the fault depression feature in new era, multiple source, and rapid deposition. There exist many problems in conventional stratigraphic division and correlation and traditional sequence division. Based on the clear understanding of two third-order sequences of Wanchang Formation in southern Luxiang fault depression, analyzing the attributes of maximum entropy spectrum, fourth-order sequences are identified accurately. The method has many advantages such as no limit to sampling length and higher resolution to the spectra. It may be used to accurately identify the location of maximum flooding surface. Furthermore, it provides a more intuitive understanding of the characteristics of system tract and cycling within the third-order sequence.

Yitong Basin is a complex fault depression basin with large-scale reserves explored in Jilin Oilfield in the past ten years. Structural interpretation and glutenite reservoir prediction are always difficult in the basin. During the process of probing into seismic data interpretation applicable to the basin, by optimizing and combining multiple applicable seismic technologies, basal conglomerate and basement granite of the target layer of the basin are identified by using instantaneous-phase attribute technologies. Effective structural interpretation of old data of the basin is fulfilled by combining the technology of time slice with the 3-D visualization technology. Lithologic traps are identified effectively based on the combination of seismic attribute analysis and wave impedance inversion.

Gas exploration in deep southern Songliao Basin is launched along with the breakthrough made in Changshen-1 well. Research results show that the volcanic rocks are the main gas reservoirs of the area and they have favorable reservoir capacity. Now volcanic rocks have been drilled in more than 60 wells of the area, featuring in multiple development phases, complex composition, and big difference in gas bearing. So systematic methods appropriate for volcanic identification are needed urgently. On the basis of in-depth study of the geological model and formation mechanism of volcanic rocks, through the combination of new geophysical exploration techniques and geological theories and using logging data, seismic data, gravitational data, and magnetic data, the characteristics of volcanic rocks in seismic profiles and logging curves are studied systematically, and a set of methods appropriate for identifying and describing volcanic rocks in Jilin exploration area are summed up. The research results may guide the deployment of Longshen-1, Longshen-2, Longshen-101 wells effectively. Great breakthroughs have been made in the exploration for deep gas in Yingtai fault depression

The volcanic rocks are buried in the depth of more than 3,500m in southern Songliao Basin, so the development effect by using vertical wells is not so satisfying. Through demonstration the method of using horizontal wells and the underbalanced drilling technique are decided to be used to realize high-efficiency development and better protect gas reservoirs. Unfavorable factors exist for Changshen horizontal well 1, such as high bottom hole temperature, long time of construction in the horizontal section, and difficult protection of sensitive gas reservoirs. Analysis shows that some problems may exist, such as wall instability and collapse, differential pressure of high-temperature drilling fluid, the pollution and damage of drilling fluid to gas reservoirs. Study is carried out including the high-temperature wall stabilization technique for deep underbalanced horizontal wells, the high-temperature rock-carrying lubrication technique, and the gas reservoir protecting technique. Good results are obtained through field application, and systematic high-temperature deep horizontal drilling techniques are developed, meeting the requirement of high-efficiency development of deep gas reservoirs.

The burial depth the reservoir of Changshen 5 well is 5,200m and the temperature reaches as high as 183℃. In view of the characteristics of the reservoir, lab test is launched on the formulations of ultra-high temperature and low-damage fracturing fluid, high-temperature crosslinker and synergist are synthesized.Meanwhile, performance evaluation is conducted on the new carboxy methyl-guanidine (CMG) ultra-high temperature fracturing fluid system. Lab test results show that the CMG fracturing fluid features in high temperature (180℃), low concentration, low residue, low damage, and low friction. The fracturing fluid system has been applied to Changshen 5 well successfully, and the production was enhanced a lot.

Songyuan City has high rise towers and the Songhua River crosses the city. It is surrounded by dunes, woodland, and farmland, Fuyu oil pipelines and facilities are construed throughout the city. Seismic acquisition is difficult to be launched in the city because it has complicated surface conditions, shallow target layers, and too many complicated faults. Through repeated demonstration, two major techniques are adopted for seismic acquisition, one is launched in the city including the design of shot points and receiver points, the combination of vibroseis with explosives, the multi-way surface investigation, and modeling all based on satellite photos, the other is high-resolution acquisition of small face, point-by-point depth design, and high-resolution static correction. They ensure the integrity and accuracy of the information of target layers. The techniques of denoising before stack, high-fidelity processing and residual static correction are used for seismic processing to improve the accuracy of information. Guided by the phase mode, the techniques of well seismic calibration and full 3-D seismic interpretation are used for interpretation, describing the faults, structures, and sand bodies accurately. Good results have been obtained by using the above methods, laying solid basis for the adjustment of the programs of exploration and development in Fuyu old oilfields, providing sufficient basis to prove and use Yangdachengzi reservoir. Hence the purpose of finding oilfields below oilfields and continuous production of old oilfields is fulfilled.

The concept of technical supervision is introduced in brief, the three basic characteristics of technical supervision in petroleum engineering, i.e. legal, technical and administrative characteristics are discussed, and the important role of technical supervision in petroleum engineering is analyzed. At the end, the development direction of technical supervision in petroleum engineering is analyzed from the perspectives of humanmanagement, resource allocation and effective use of the third-party. Furthermore, important suggestions are presented for technical supervision in petroleum exploration engineering in the future