OIL&GAS GEOLOGY-2002, Volume 23 Issue 2

Dai Shaowu, He Ziai, Wang Jinyi, Yu Qixiang

2002, 23(2): 107-114,126. doi:10.11743/ogg20020201

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High standard and strict requirement for bulk sealing off system have been determined by nature of easily loss of natural gas.Evaluation of the thinking shall be guided by the theory of board bucket(wooden bucket effect) and more attention shall be paid to the decisive role of locality over bulk in particular.With distinction between sealing off of natural gas and petroleum,emphasis must be placed on stereo and effectiveness when mentioning intension of bulk sealing off system.practical oil and gas exploration in eastern and northeastern Sichuan indicates that overpressure-static pressure fluid system in the lower part(Mesozoic-Palaeozoic) and high pressure-static pressure fluid system in the upper part(Mesozoic-Cenozoic) jointly constitute the stereo of bulk sealing off system,in fact a combined-sealing off system is composed of physical property,concentration and pressure.Effectiveness is decided by(1).buried depth;(2).regional hydro-dynamics;(3).late uplift;(4).time limit of uplift.Stereo is constitution and effectiveness is reconstruction,only by putting these two into one,can maximum function of bulk sealing off system be fully brought into play.

SEQUENCES, SYSTEM TRACTS, AND SUBTLE HYDROCARBONPOOLS IN LACUSTRINE BASINS

Xue Liangqing

2002, 23(2): 115-120. doi:10.11743/ogg20020202

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Main controlling factors of sequence development in lacustrine basins are tectonic uplift and subsidence,lake-level changes,and changes of sediment supply rates.Transformation of regional tectonic regimes in stacked basins is the basis for defining the first-order sequence.Sedimentary products of tectonic episodes consist of the second-order sequence,the third-and higher-order sequences chiefly reflect changes of paleogeography and depositional styles.Isochroneity of system tracts of lacustrine basin under various conditions is obviously different.System tracts defined above are isochronic when change ratios between compatible space of one "sedimentary field" controlled by one extrabasinal sediment supply or multi "sediment fields"controlled by several extrabasinal sediment supplies and sedimentation:rates are all more than 1 or less than 1.Lowstand sandstone and conglomerate bodies controlled by structural break(zone) in fault-depressed type lacustrine basin and delta-front sandstone bodies underlainl and overlain by two largest flooding acustrine mudstones in depressed-type lacustrine basin are main targets for explorating subtle pools.

SEQUENCE STRATIGRAPHY OF JURRASIC COAL-BEARING MEASURE AND SUBTLE TRAP IN THE NORTHEAST EDGE OF JUNGGAR BASIN

Zhu Xiaomin, Kang An, Zhang Qin, Zhang Manlang, Kuang Jun, Wu Xiaozhi, Han Jun

2002, 23(2): 121-126. doi:10.11743/ogg20020203

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There was a topographic break in the northeast edge of Junggar basin during Jurassic Period.Middle-Lower parts of Jurassic can be divided into 4 sequences according to sequence boundaries,such as unconformity and thick coal bed.Lowstand system tract,lacustrine transgression and highstand system tracts in the interest area can be subdivided by the repeated pattern of stratigraphy,locally distribution of coal-bearing measure and the location of topographic break in sedimentary sequence.Lowstand system tract is characterized by the incised valley(braided river) sediment,lacustrine transgression system tract is represented in nature by the widespread of lacustrine sediment and highstand system tract is featured by the prograding delta.It is predicated that,on the basis of establishing a model of sequence stratigraphy of coal-bearing measure in lacustrine basin with a topographic break belt and analyzing the conditions of hydrocarbon accumulation,the incised valley in Lowstand system tract and distant lenticular sandbody in front of the delta in highstand system tract is the area where subtle trap formed.

ORIGIN AND SEDIMENTARY SEQUENCE OF Es_3-Es₂ IN SHAHEJIEFORMATION OF DONGYING DEPRESSION

Jiang Zaixing, Yang Weili, Cao Yingchang

2002, 23(2): 127-129,153. doi:10.11743/ogg20020204

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Member Ⅲ-lower submember of Member Ⅱ in Shahejie Formation of Dongying Depression can be divided into Ⅲ third-order sequences on the basis of seismic data,lithology and electric characteristics etc.The bottom of sequence(SSI) corresponds to the lower submember of Member Ⅲ of Shahejie Formation,characterized by lowstand system tracts undeveloped,only lacustrine transgression system tracts and highstand system tracts developed,all of theses are controlled by the early tectonic subsidence and climate.Middle sequence(SSⅡ) represents the mid-submember sedimentation of Member Ⅲ in Shahejie Formation and has similar nature of the bottom sequence.SSI and SSⅡ are all T-R cyclic sedimentation.Top sequence(SSⅢ) representing sedimentation of the upper submember of Member Ⅲ-lower submember of Member Ⅱ in Shahejie Formation(forming Lowstand system tracts,water transgression system tracts and highstand system tracts) is a complete cycle.SSⅡ was formed under the conditions of tectonic activity relatively weak,climate relatively dry and water supply insufficiently.

EXPLORATION OF SUBTLE RESERVOIR IN PROLIFIC DEPRESSION OF BOHAI BAY BASIN

Yuan Xuanjun, Qiao Hansheng

2002, 23(2): 130-133. doi:10.11743/ogg20020205

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The theory of prolific depression is essentially to let us have an idea of "depression fully filled with oil and gas" namely,the depression with rich source rocks,high resource abundances,enriched-oil and gas,and to search for not only reservoirs in positive structural zone,but also more important to search for reservoirs in negative structural zone as well,and to search for different subtle reservoirs in particular. There are various subtle reservoirs such as lithologic reservoir,stratigraphic reservoir,especially as well as volcanic rock reservoir and buried hill reservoir etc.,the reserves of which making up almost 40% of the total proved reserves in the study area.The prolific depression in Dongyang,Zhanhua,Western and Eastern Liaoning,Damintun,Raoyang,Qikou and Banqiao etc.have been discovered with high resource abundances,and large well- developed subtle reservoirs with great potential for the exploration of oil and gas. Deep buried hill,turbidite body in the sag zone,sand body in the steep gradient zone,the third member from Shahejie- Formation and the Mesozic volcanic rock,water encroachment overlapping delta sand body in the gentle slope zone as well as complex subtle blocks etc.are believed to be major projecting areas for the exploration of oil and gas in prolific subtle reservoirs.

CHARACTERISTICS OF SEQUENCE STRATIGRAPHY IN THE SALINE LAKE BASIN

Huang Chunju, Chen Kaiyuan, Yang Xianghua

2002, 23(2): 134-138. doi:10.11743/ogg20020206

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There are some distinctions between sequence stratigraphy of carbonate rock and sequence stratigraphy of the saline lake basin.Therefore,the analysis of carbonate rock sediment must start from the analysis of climate,structure and sources of saline material etc.and use geochemical characteristics of the saline sediments to reveal changes of the lake surface so as to divide the saline sequence.Isotope of carbon and oxygen in the ingression of water system tracts in Qianjiang Formation of Qianjiang depression is lighter than those in the highstand and lowstand system tracts.Boron content has a similar change regularity,boron content in the late period of highstand and lowstand system tracts is normally higher while in the ingression of water system tracts it's gradually becoming lower.Qianjiang Formation of the Qianjiang depression could be divided into 3 major system tracts and 7 sequence stratigraphies on the basis of combined analysis of its different sediment sources and comprehensive factors of its palaeo-topography.

SALINE LAKE SEQUENCE STRUCTURE OF DONGPU DEPRESSION AND SUBTLE RESERVOIR

Yang Xianghua, Chen Kaiyuan, Shi Wanzhong, Zhang Hongan, L? Xinhua, Huang Longwei

2002, 23(2): 139-142. doi:10.11743/ogg20020207

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Lowstand system tracts in rock salts sequence of Dongpu depression are predominantly composed of thick-massive rock salts intercalated by thin layers of mudstone and sandstone,showing in seism a continuous reflection with strong amplitude.The lacustrine transgression phase is characterized by sandstone with intercalation of thin layers of rocks salts and gravitational flow rock of deep and semi-deep lacustrine phase.Highstand system tracts are formed by thick-massive rock salts intercalated by thin layers of mudstone and sandstone.Palaeobiological fossil data collected from Shahejie Formation of Dongpu depression indicate that the development of algal-biologies,lack of freshwater biologies and mussel-shrimps appeared in layer have given a clear picture of the depositional environment of rock salts characterized chiefly and alternately by moisture and semi-arid climate,and with clastics supply even in the background of reduced deep lacustrine and semi-deep lacustrine phase.Subtle traps of Saline lake in this region are developed commonly in salt gravitational-flow fans and gravitational lenticular sandbodies of salt clastics.

ORIGIN OF LOWSTAND FAN IN FAULTED-TOPOGRAPHIC BREAK & PLAY'S CHARACTERISTICS

Jiang Xiufang, Zong Guohong, Guo Yuxin, Li Chuanhua, Xiang Lihong

2002, 23(2): 143-144. doi:10.11743/ogg20020208

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The bottom boundary(interface) of Ⅲ sequence of Jurassic in Junggar basin could be chiefly divided into following three types in structure:(1).unconformity with basal conglomerate;(2).pseudo-conformity with weathered layer;(3).conformity with apparent variation in sedimentary type etc.In the waveform seismic phase of 40ms extension upwards and downwards in the bottom boundary of Ⅲ sequence of Jurassic,high frequency of waveform seismic type Ⅰ-Ⅱ corresponds to sediments of sandstone layered with mudstone;Low frequency of type V-VI is in correspondence with large complete set of sandstone sediments while type Ⅲ-IV waveform is in between above two types.The amplitude of seismic wave is connected with rock assemblage on the bottom boundary,the medium stronger amplitude corresponds to the sand-mudstone assemblage as well as to the assemblages of conglomerate and silt rock,the weaker amplitude is in correspondence with the large complete set of sandstone assemblage while the medium intensity of amplitude is in between above two assemblages.Moreover,the low frequency seismic wave and the medium-stronger amplitude have a good correspondence with the progradational reflection of seismic.It is believed that,by a comprehensive analysis of waveform seismic phase,the amplitude and the reflection structure,the widespread of sandbodies in large area of northwestern slopes of Mahu Lake and Shinan-Mobei region in the central part,of which sandbodies of underwater fan of Che-Guai,Mahu braided delta,delta of Zhongguai meandering river and Shinan-Xiayan meandering river delta are well-developed and are favorable for forming nonstructural traps and have good potential for prospecting hydrocarbon.

ANALYSIS OF SEQUENCE STRATIGRAPHY OF EOGENE SYSTEM IN YI-SHU GRABEN

Chen Shoutian, Zhang Kemin, Wang Qinghai, Meng Qi'an, Ren Yanguang

2002, 23(2): 150-153. doi:10.11743/ogg20020210

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Yi-Shu graben had undergone two major development processes of early faulted-depression and late died-out.These processes could correspond to the stage of major tectonic evolution,forming 4 overlapping sequences and 20 sequences.A comprehensive analysis of the distribution of source rocks and the characteristics of palaeocurrent etc.indicates that there are 3 resource areas in the upright fault depression.From Xinancun Formation to Dalianhe Formation,sediments from the deep lake facies might have migrated gradually to the sediment center,causing gradually change of layer position of hydrocarbon rocks which existed in the stage of strong faulted-depression and early stage of faulted-depression.Oil and gas accumulations in Yi-Shu graben are mainly distributed in lowstand system tracts while only small amount of the accumulations distributed in highstand system tracts.

APPLICATION OF DEPOSITIONAL BASE-LEVEL CONCEPT IN SEQUENCE STRATIGRAPHIC DIVISION AND PREDICATION OF HYDROCARBON

Cao Yinghui, Chi Yingliu, Xue Liangqing

2002, 23(2): 154-158. doi:10.11743/ogg20020211

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Changes in depositional base-level cycle control the development and evolution of sequence stratigraphy.The depositional base-level of continental basin,different from that of marine basin,is neither sea-level nor lake-level but an abstract contact equivalent to river depositional equilibrium profile.Different position with different size of compatible space during depositional base-level cycles resulted in the distribution of sediments in volume within various facies leading to the variation of stratigraphic-accumulation patterns and symmetries of stratigraphic cycles.Therefore,these variations are just markers for correlation of sequence division.According to the principal of distribution of sediments in volume in the depositional base-level cycle,the correct chronostratigraphic correlation of sequence stratigraphy with high resolution shall be that of rocks to rocks,rocks to surfaces,surfaces to surfaces or contacts to contacts instead of the correlation of lithology or isostratigraphy.During the change of depositional base-level cycle,there were very close relations between differences in the variation of compatible space size and the development of source rock,reservoir rock and cap rock in different tracts as well as the unconformity surface and the distribution of litho-pinch out.

SUBTLE TRAPS AND PREDICATION OF FAVORABLE AREAS IN SOUTHERN SONGLIAO BASIN

Li Qun

2002, 23(2): 159-161,178. doi:10.11743/ogg20020212

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Southern Songliao basin can be divided into 4 types of litho-trap and composite trap namely,channel sandbody,progradational leafy sandbody,fault-litho-trap and structural-litho-trap.Channel sandbody in seismic profile displays strong amplitude,preclination of low frequency and down concave reflection.If river bank is steep,the river bed can be defined by termination point of horizontal reflection,point sandbar showing slightly convex while channel displaying the characteristic of concave.Progradational reflection configuration of the progradational leafy body shows gentle downlap or toplap.Deltaic sheet sandbody can be defined by warped part of progradatioal bed or warped part of toplap pinch out bed.Branch channel sandbody can be identified by the abnormality of structure and waveform through amplitude.Changes for amplitude and waveform in strata series of deltaic progradation are closely connected with the sandbody.Daqingzijing area and southeasthern source area are believed to be favorable prospecting oil and gas reservoirs while Qianan-Gudian area is considered to be relatively favorable prospecting oil and gas reservoir.

EXPLORATION TREND FOR LITHO-OIL RESERVOIR IN 3rd MEMBER OF SHAHEJIE FORMATION OF HUIMIN DEPRESSION

Zhang Yu Qiu, Guiqiang, Li Chenyi, Fan Cuntang

2002, 23(2): 162-165. doi:10.11743/ogg20020213

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sequence interfaces can be identified through demarcation by well drilling and seismic detection in 3rd member of Shahejie Formation of Huimin depression,of which T7,T6,,T4,T3 are believed to be maximum lake flooding plane and T6-1,T4-1,T-3 are discovered to be transitional plane of sedimentary process.Therefore,3rd member of Shahejie Formation can be divided into 3 middle basic level cycles(C3,C2,C1).During C3 period,small-scale of turbidite fans were formed due to intensely deposition of the basin.During C2 period,central uplift belts were formed.In C1 period,wide spread of stable mudstone intervals were developed due to gradually weakening of fault-controlled activities.Litho-hydrocarbon reservoirs might have been developed in Jishan sandbody and in the area of JiangJjiadian on the basis of above sequence analysis.Jishan sandbody was largely formed in the period of C2 cycle,developing in turn turbidite fan sandbodies,delta of twist embankment(offshore underwater fan body)-turbidite fan litho-traps were developed along down-dropped blocks of Xiakou fault.

EVOLUTION AND SEQUENCE STRATIGRAPHIC FRAMEWORK OF LOWER CRETACEOUS IN CHAGAN DEPRESSION

Guo Yanru, Yu Junmin, Fan Tailiang

2002, 23(2): 166-169,182. doi:10.11743/ogg20020214

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Lower Cretaceous of Chagan depression,situated in the northwest corner of YinE basin,can be divided into one first-order sequence;two second-order sequences and seven third-order sequences according to its data of seism,lithology,palaeobiography, geochemistry and well-logging etc.Ⅰ annd Ⅱ order sequences were shaped during Ⅰ and Ⅱ member deposition of Bayin Gebi Formation,Ⅲ,Ⅳ and Ⅴ-order sequences were formed in the deposition of Suhongtu Formation while Ⅵ and Ⅶ-order sequences formed in the deposition of Yingen Formation.Well-logging data collected from Chagan depression indicate that 58% oil and gas bearing-formation are distributed in lowstand system tracts,30% in highstand system tracts and 12% in lake ingression system tracts.

ANALYSIS OF SEQUENCE STRATIGRAPHY IN CHANGLING DEPRESSION

Wei Zhiping, Tang Zhenxing, Jiang Tao, Jiang Chengfu, Wang Anhui

2002, 23(2): 170-173. doi:10.11743/ogg20020215

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On the basis of the larger regional unconformity,Changling depression can be divided into 2 second-order sequences of Quantou Formation-Qingshankou Formation and Yaojia Formation-Nenjiang Formation.Marked by the local unconformity and sedimentary transformation base,Qingshankou Formation can be subdivided into 4 third-order sequences.In Daqingzijin region situated in front of the deltaic sandstone body of Baokang,sandstone bodies are widely spread in sequence S1 and S2 of lowstand system tracts which are main oil-bearing strata in that region.Sequence stratigraphy does not only control the type of oil and gas accumulation but also control the nature of oil bearing.60% of industrial oil and gas wells are estimated to locate in the low level system tracts.

CHARACTERISTICS OF GAOBEI SUBTLE HYDROCARBON RESERVOIR AND EXPLORATION METHOD

Wang Xudong, Lu Guixiang

2002, 23(2): 174-178. doi:10.11743/ogg20020216

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Gaobei subtle hydrocarbon reservoir is situated in northern flank of Gaoshangpu buried hill of Nanpu depression. The reservoir was formerly considered to be a structural hydrocarbon reservoir controlled by the fault.It is discovered by re-analyzing thickness of the skeletal sandstone and orientation of material sources that the reservoir is a type,composed of "sand wrapped by mud",of litho-reservoir against structural background with feature of high production of energy initially and degrading quickly late on.Exploration process for the reservoir indicates that a thorough study of micro-sedimentary phase of reservoir shall be emphasized in the first place when searching for subtle hydrocarbon reservoir,restoring the reservoir by means of seismic inversion,defining the type of hydrocarbon reservoir by studying on comprehensive analysis results.

ORDOVICION REEF IN LUNAN-BACHU AREA AND THEIR RESERVOIR CHARACTERISTICS

Hu Minyi, Zhu Zhongde, He Ping, Zhang Jun, Wang Qingchun

2002, 23(2): 179-182. doi:10.11743/ogg20020217

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Ordovicion reef in Lunan-Bachu area of Tarim basin have been discovered recently in Middle Ordovicion Yi Jianfang Formation and Upper Ordovicion Sang Tama Formation.The reef-build-up organism are mainly composed of Calathium,Lithistida,Batostoma and Archaeoscyphia etc.The reef body,small in size and variety in type,is generally made up of reef base,reef core and reef cap.Characterized by low-porosity-low permeability or low porosity-middle permeability based on the analysis of porosity and permeability,rocks of reef reservoir are not good in general,but the porosity of reef base and reef cap is higher than that of reef core.The reservoirs,controlled by sedimentary structure and diagenesis,are mainly in types of fracture and pore-fracture.

CHARACTERISTICS OF O₂₊₃ LIMESTONE RESERVOIR RIFT IN TAZHONG 1# FRACTURE ZONE

Qin qirong, Liu Sheng, Su Peidong

2002, 23(2): 183-185,202. doi:10.11743/ogg20020218

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O₂₊₃ limestone reservoir rift in Tazhong 1# fracture zone can be divided into two types of structural rift and non-structural rift.It is believed that,on the basis of intersected relations of the rift and testing results of homogeneous temperature of calcite packet and rock Kaiser,O₂₊₃ limestone had gone through three times of tectonic movements,forming corresponding 3 phases of structural rifts.During the period of Late Caledonian and Early Hercynian,after the formation of diagenetic rift of paralle-bedding plane along O₂₊₃ limestone plane in the process of static pressure and in the process of NE-SW structure,a series of conjugate shear rifts of vertical bedding plane,high-angle stylolites as well as longitudinal and transverse tensional rifts due to accumulation of stress.The rifts of this period are filled with calcites.During Late Hercynian,early rifts were enlarged by the tectonic movements and new shear rifts were produced.In the late period of Late Hercynian,the tectonic movements were relatively static,rifts were filled with semitransparent calcites.Unfilled vertical structural shear rifts with good orientation of non-big scale were formed by the influence of the tectonic movements again during Himalayan period which played very important role in hydrocarbon accumulation.

CHARACTERISTICS OF GAS RESERVOIR AND ITS CONTROLLING FACTORS IN Es³ OF QIAOKOU STRUCTURE

Wang Shenglang, Ren Laiyi, Wang Hongbin, Huang Guoping, Zhang Hong

2002, 23(2): 186-189. doi:10.11743/ogg20020219

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Gas reservoir in Es³ interval of Qiaokou structure is characterized by its great buried depth,long gas-bearing interval,poor physical property,great change longitudinally and transversally,low productivity of gas bearing strata and unstable pressure.It is believed,by analyzing structure of litho-composition,sedimentary facies belts,physical property,overburden,structure and hydrocarbon evolution,that sedimentary facies is the main factor among several controlling factors,gravitational flow channel sandbody and physical property of fan-braided channel in the sublacustrine fan is not good but also buried in mudstone of hydrocarbon genetic depression which is favorable for hydrocarbon trapping and accumulating to reservoir.Therefore,it is necessary to stress the importance of next step exploration by strengthening a carefully study of sedimentary facies,analyzing those favorable sedimentary facies by combining seismic data with data of well-logging,predicating reservoir.

DEEP BASIN GAS RESERVOIRS OF LATE PALAEOZOIC IN NORTHERN ORDOS BASIN

Li Kemin

2002, 23(2): 190-193. doi:10.11743/ogg20020220

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A large stable regional slope formed by the process of uplifting of Ordos basin as whole during Late Palaeozoic Era provided necessary structural conditions for the generation of deep basin gas.With good gas-genetic conditions,coal measure strata in both Taiyuan Formation and Shanxi Formation laid a foundation materially for the generation of deep basin gas;With great thickness,widely distribution and tight lithology,sandbodies in Taiyuan Formation,Shanxi Formation and Lower Shihezi Formation are decisive factors for generating deep basin gas.Gas reservoirs along Yishan slope and Tianhuan depression mainly produce gas,while western Shanxi fault fold belt to west edge of fault fold belt produce both gas and water,No.12 Yi Well to No.2 Ha Well produce water only.Located in gas-bearing belt of deep basin reservoir and with rich abundance,the main body of Yishan slope and Tianhuan depression will be the most potential for gas exploration.

PREDICATIVE METHOD OF PRODUCTIVE CAPABILITY OF NON-FLOWING OIL WELL AND ITS APPLICATION

Miao Mincai, Wang Weiying, Zhang Gongshe

2002, 23(2): 194-195. doi:10.11743/ogg20020221

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Use data of bottom pressure restoration of well with right angle coordinate system to draw P-T curve,and then chose two time-points(t₁,t₂₃) from the average value,read out corresponding P₁,P₂ and P₃ value,produce time curve slope and productivity index on the basis of the plate.Interval between each point shall be chosen as following rule;interval between t₁ and t₂ shall not be too small,40mm for t₁ and 300mm for t₂.The establishment of this method is mainly on the basis of theory of slug flow test.Predicative results got from an oil field in eastern China by this method are almost as same as practical testing results.

STUDY ON CARBONATE FRACTURE-CAVITY SYSTEM ——STATUS AND PROSPECTS

Chen Qinghua, Liu Chiyang, Wang Shuxiang, Li Qin, Wang Shaolan, Xiao Hongping, Zhang Fengqi

2002, 23(2): 196-202. doi:10.11743/ogg20020222

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With well development of rift and karst,carbonate rock stratum might be a high quality of reservoir,Tahe No.4 oilfield is a typical example.The rift can be divided into various types on the basis of factors of its distribution pattern,occurrence,size,filling,connection and origin.stages division of the rift can be done according to various intersect relations of the rift,various filling compositions,filling stages,logging corresponding characteristics and different structural stress fields.Lithology,rock stratum thickness,fracture process,structural stress field,local structure,stratum load and karst process are all main controlling factors for the development of the rift.Palaeokarst process mainly consists of several types of sediment karst,weathered crust karst and karst of rift-cavity system etc.Paleaokarst had experienced periods of syndeposition,crust of weathering,burial and epigenetic variation in the course of evolution.Paleaokarst might be classified,paternally as karst trace,karst cave,karst pore and cave,vertically as surface karst belt,seepage flow karst belt and underflow karst belt.The development of paleaokast is controlled by several factors of climate,lithology,structure,hydrology and landform.The study of karst of rift-cavity system shall be divided into 3 stages:study karst of rift-cavity' occurrence,organizational system,development,origin,filling and distribution by observing outcrops and rock cores.Distinguish regularity of rifts and their distribution and development by studying and interpreting data collected from well drilling,logging,seism and rifts logging etc.predicate karst of rift-cavity by seism,logging and simulation of structural stress fields.The study of karst of rift-cavity system shall be based on improving and perfecting available technical methods,enforcing application of new technical methods,stressing the importance and orientation of comprehensive application of various methods by seeking more effective theories and technical methods.

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