针对普光气田长兴组礁滩体分布规律认识不清楚、台缘礁气水关系复杂的问题,开展了长兴组礁滩体地震识别及台缘礁内幕精细刻画工作.通过井震精细标定,明确了礁滩体储层地震响应特征,利用多属性分析等手段对长兴组礁滩体进行宏观识别,结合最新古地貌恢复结果分析了礁滩体平面展布规律;利用瞬时相位与波阻抗反演结果对台缘生物礁群的内幕结构进行了精细刻画,并结合生产动态资料分析了单礁体储层的连通性.结果表明:长兴组发育台缘礁群与台内礁滩复合区2类礁滩体,礁滩复合区的分布受到台缘礁间水道控制,宽水道对应礁滩复合区面积大,窄水道对应礁滩复合区面积小,平面上呈近似扇形分布;台缘礁群在长兴组中上部可识别2期次50个单礁体,呈现5类不同的叠加发育模式,并且2期次的单礁体储层互不连通,同一期次侧向叠置的单礁体储层普遍连通.研究结果对普光气田长兴组下步勘探及开发具有一定指导意义.

以普光地区长兴组和雷口坡组为例,展示了地震资料岩性标定在碳酸盐岩储层预测中的应用流程和思路。首先在井点处系统分析储层岩性组合的地震响应和横向变化特征;再根据实际地质情况对地震相变进行合理解译,获取相应的地震地质认识;最终结合认识将各井点处的标定结果拓展到横向上。在实际应用中,通过岩性标定识别出了能准确代表长兴组厚储层的地震响应及横向上的变化规律,为储层预测提供了依据;将90°相位转换更好的应用到岩性标定中,解决了雷口坡组薄储层的精细识别问题。应用实例表明,精细的岩性标定能够简化解释工作,并有效提高储层预测的精确度和可信度。此外,碳酸盐岩地层岩性变化缓慢,经常出现一定范围内岩性和物性相对稳定的地层,合理的利用这类地层能够有效提高岩性标定和储层预测结果的准确性。

Since there are multi-types of multi-direction faults in Dongpu depression,Wenmingzhai Oilfield is an extra-complicated faultedblock oilfield with multi oil-bearing layers.As one of the important developing blocks,Ming 1 block has multi sub-level faults and extremely complex structures.The target lower Es2 is characterized by thin single layer and large lateral alternation.Small fault recognition, low-relief structure interpretation and thin sandbody prediction is difficult in the area.By using the new acquired high-precision 3-D seismic data,we proposed the methods including combination of multi-directions cross-sections and time slices,constraint by coherent slice and seismic sections as well as dynamic and static development data,to carry out fine interpretation of small faults and crosswell buried fault.Through sensitivity analysis of seismic attributes and comprehensive application of multi seismic attributes,the sandbodies were quantitatively characterized.Through the above research, the distribution of crosswell faults with the displacement longer than 10m was interpreted,and the crosswell alternation of single sand bodies thicker than 5m were characterized.

Seismic exploration accuracy meets higher and higher requirements since the exploration targets in Dongpu Sag tend to be more subtle and complicated.For this,this paper puts forward a new method for acquiring horizon velocity based on joint inversion of stack velocity and migration velocity,improving the accuracy of velocity calculation.Through study on methods for establishing velocity field,the technology of establishing velocity field on the basis of combining such information as seismic velocity,logging,drilling and structural horizon is developed,and the velocity field reflecting the macroscopic law of velocity distribution is obtained,which is in good agreement with the well.Integrating the concept and application of seismic velocity,this paper defines the correlation of various types of velocity and its applicability,providing a complete velocity field solution for different phases of seismic exploration.Based on coordinate positioning and unified format transformation of seismic velocity data,the velocity base of all over Dongpu Sag is established,supporting seismic imaging,variable velocity mapping,and prediction of regional formation pressure technically,and yielding good results.

The prospecting extent in the whole Bachu uplift of Tarim Basin is relatively low,which however is a potential area for oil and gas exploration.The poor near-surface shooting conditions,deeply buried target areas and deep geological conditions result in the serious seismic data static correction problem,highly-developed interference wave,difficulties in correct recognition of multiple wave,improvement of the energy of deep reflection wave and accurate obtaining of the velocity and migration imaging.Low S/N ratio data and poor quality have greatly restricted the capability of solving the geological problem by using seismic data.Through an analysis of newly acquired seismic data,the authors accurately built a near-surface model for calculating accurate static values and enhancing pre-stack attenuation.Various amplitude energy compensation methods were used for accurate velocity analysis to improve the precision of the velocity field,and inner mute was adopted in near traces.Integrated application of cascade methods was adopted to eliminate multiple interference,migration method was chosen for improving the imaging quality of deep weak signal and S/N ratio in this low S/N ratio area and,as a result,event continuity and structure imaging quality were greatly enhanced and improved,thus attaining superior applying results.

Fractured mudstone reservoirs are always being found in the exploration history in Dongpu Depression.However,because of its concealment and complexity,the prediction and exploration about this kind of reservoir is very difficult.The fractured mudstone reservoirs have been found by chance in initial exploration stage.So,how to identify and predict the fractured mudstone reservoir by the use of seismic data is a key technique which requires to be resolved in the exploration of this kind of reservoir.In this paper,through the analysis of the geological and seismic features of the fractured mudstone reservoir in upper Es3 salt interbed in Liutun Sag,the characteristics of core and logging data about fractured mudstone reservoir have been studied by means of comprehensive explanation of seismic sections,drilling and well logging data.The paper conducts the petrophysical analysis and the vertical and lateral seismic response feature analysis for single well and multiple wells on the basis of normalization for logging data.It determines the geophysical features in this area which are the strong amplitude,low density,low velocity and low-impedance.On the basis of the accurate selection of sensitive seismic parameters,the fractured mudstone reservoir has been predicted and identified in this area by using the seismic attributes analysis and wave impedance inversion.And good application effects have been achieved.

The main objective of conventional 3D seismic geometry design is to obtain regularly sampled stacking dataset, which can be used to achieve good images through post-stack migration.However, pre-stack migration has strict requirements on seismic geometries.In order to exert the technical advantages of pre-stack migration and improve the accuracy of seismic images, it is very important to design seismic geometries based on pre-stack imaging. This article puts forward an approach of seismic geometry design based on pre-stack imaging.The first step is to design the basic spatial sampling of seismic geometry based on the anti-aliasing criteria of pre-stack migration.The second is to design the layout of seismic geometry according to the rule of regular sampling and uniform bin attributes. Then, it optimizes step by step and finalizes seismic geometry by using techniques such as focal beams, pre-stack migration response of scatter point, forward modeling, and wavefield illumination.This method has been applied to high accuracy seismic exploration of the Zhongyuan Oilfield in recent years and it has obtained very good results.

Utilizing the new data of gravity, magnetic, and magnetotelluric survey, we analyzed the characteristics of the three geophysical attribute (gravity, magnetic, and resistivity) interfaces and the deep architecture and structure of Kumkuli basin. The research results can provide basic data for early basin structural study. From coupled basin and mountain system, analysis of the structure, and evolution of Kumkuli basin, we found that there was zoning from north to south and from west to east. Kumkuli basin has three structural architecture layers including metamorphic crystallization basement, fold basement and sedimentary cover. Kumkuli basin can be divided into three structural units, two depressions, and one uplift. Structural evolution of the Kumkuli basin can be divided into five evolution stages, including Kumkuli microcontinent formed in Sinian-Ordovician, suture around Kumkuli basin formed in Eopaleozoic, retroarc foreland basin formed in Neopaleozoic, rejuvenated foreland basin developed in Mesozoic, and strike slip and compression basin developed in Cenozoic.

In 2005,Zhongyuan Oilfield Company carried out high-precision 3D seismic exploration in Machang area of Dongpu sag,in which the design and demonstration of geometry scheme is a key step.The main geometries utilized in the sag in the past are first analyzed by using forward modeling techniques.By comparison of simulated data,the knowledge that imaging effects can be improved with increasing spatial sampling density is cognized.The acquisition geometry is determined by analyzing the two geometries with higher spatial sampling during the survey design of high-precision seismic exploration in the area.Focal analysis shows that the designed geometry has good property in amplitude accuracy and in horizontal illumination,which is favorable for lithology recognition in final seismic data.With the practice of high-precision seismic exploration in the area,imaging quality is significantly improved and very good results are achieved,which also proves the correctness of the geometry design.

When velocity anisotropy exists in subsurface rocks,the conventional isotropic migration methods may lead to not only wrong imaging position but also inaccurate image quality.This paper presents a method of anisotropic pre-stack time migration with real 3D seismic data in Dongpu sag.First,velocity and anisotropy parameters are obtained by using bi-spectral velocity analysis,and then the pre-stack data is migrated with an anisotropic method.Good imaging results are fulfilled in real 3D data.

When velocity anisotropy exists in subsurface rocks,the conventional isotropic migration methods may lead to not only wrong imaging position but also inaccurate image quality.This paper presents a method of anisotropic pre-stack time migration with real 3D seismic data in Dongpu sag.First,velocity and anisotropy parameters are obtained by using bi-spectral velocity analysis,and then the pre-stack data is migrated with an anisotropic method.Good imaging results are fulfilled in real 3D data.

Through the discussion of the current state of lithologic & stratigraphic reservoir of Dongpu sag and the contrastive analysis of some typical basins in China,the geological conditions favorable for the formation of lithologic & stratigraphic reservoir in the sag are illustrated.The main area to explore lithologic & stratigraphic reservoir is within the area of hydrocarbon generation where structural trap is not developed.The countermeasures for exploring the lithologic & stratigraphic reservoir in the sag are analyzed and summarized.More attention should be paid to high-precision 3D information and reservoir characterization in order to effectively explore the lithologic & stratigraphic reservoir.

The carbonate platform margin of Upper Ordovician Lianglitage Formation was encircling along the Kartarke uplift,with a small gaping at western,in Tazhong area,Tarim basin.From the early to the later stage of the Late Ordovician Lianglitage Formation depositional,the platform margin migrated stepwise to the Center Faulted Zone of Kartarke uplift,and the northern of the encircling zone of platform margin migrated faster than the southern.Based on the data of wells,logging,seismic profile and other relevant analysis test,we have researched sedimentary facies,palaeo-geography,palaeo-structure and genetic model of the platform margin.According to paleo-topography,paleo-structural and waters energy environment,the four types of platform margin are divided,including steep slope-high terra,fault-high mound,fault-low mound,gentle slope-low mound,and their distribution are identified in Tazhong area.The study reveals that the different kind of platform margin had various micro-sedimentary facies and developed distinctly framework reef,barrier reef,lime mud mound and reef(mound)-bank complex.The reef(mound)-bank complex occurred frequently,decreased in size and developed immature with the platform margin migrated fast.Being in contemporaneous atmogenic rock environment,reef(mound)-beach complexes generated syn-depositional karstification,miscellaneous pores were formed when sea level was relative fall.The preserved effective pores distributed in reef(mound)-beach complexes on platform margin,formed the atmospheric lithogenic lens.Influenced by buried karstification and tectonic disruption,secondary pore spaces are developed that are corrosion pores,residual intergranular pores,and fissure pore spaces,with nonhomogeneous in intrabed and interlayer.The atmospheric lithogenic lens with 4 to 6 stages are recognized in research area,some of them were developed frequently and monolayer thickness were thin in which reef(mound)-beach complexes exists on fault-low mound and gentle slope-low mound type of platform margin.To summarize,the favorable reservoir plays are controlled by platform margin zones,high-quality vuggy reservoirs are developed in reef beach complexes,especially grain-clastic bank and reef core reconstructed by later buried karstification and tectonic disruption.Shunxi slope-break zone and Ka-4 slope-break zone developed reef beach complexes and approached source rock are new favorable prospect plays.

There exist thick marine carbonate strata of varied lithologic characters in the Lower Ordovician-Upper Ordovician Lianglitage Formation of western Tazhong area. Based on data of drill cores, logs and laboratory tests, the authors recognized three types of karstifications in the study area, namely syn-depositional, weathering-crust, and buried ones. The syn-depositional karstification occurs mainly on the platform margin of Later Ordovician Lianglitage Formation, in which atmospheric lithogenic lens are frequently seen but their sizes are not so big. The weathering-crust karstification is developed in central Kartarke uplift. The buried karstification can be divided into three stages and are distributed in areas where faulted structural belts and igneous rocks are well developed. Lithofacies and sedimentary facies, karstification and structural fissures are main factors controlling the development of Ordovician carbonate reservoirs, which constrain the development of karst reservoir rocks in different layers and positions.

台南气田为第四系生物成因气藏,埋藏深度小、气层厚度大、构造简单,有利于地震资料识别油气藏.该区以往地震资料均为常规处理地震剖面,信噪比很低、同相轴连续性差,看不出任何气层特征.为此,我们对一条过气田的测线进行了地震资料处理试验.经分析,可以认为采用主频20Hz进行目标处理最能反映气层地震响应特征,如暗点、平点、同相轴下弯、低频效应和极性反转等.依据这些特征可以预测各层段天然气藏平面分布规律,从而满足了气田开发的需求.

Reservoirs in Es4 member of Hubuzhai structure of Dongpu Depression are tight with fracture development, which are high angle and unfilling shear fractures with obvious characteristics of grouping. On the basis of core description, integral fracture recognition, lithomechanics test, 3D finite element numerical simulation is used to quantitatively predict fractural growth characteristics and distribution rules of Es4 low permeability and tight sandstones in the area. The result shows that fractures in well block of Well b1-1-b1-2, Well v353. Well v318 are highly developed, growing degree is low in the east of Well b2.

地震属性分析技术在储层横向预测中发挥着越来越重要的作用.利用多元地震属性分析技术进行储层信息预测的理论基础是,储层中岩石性质、流体性质的空间变化可引起地震反射波形、振幅、频率等地震属性的变化.本文主要阐述了利用地震属性的分类(聚类)分析和多元地震属性回归技术,来分析特定区域储层纵、横向变化特征;强调在区域地质概念模型的前提下,预测储层的分布范围和储层物性.应用实例表明,本文方法的预测结果与钻井资料吻合较好.

A foundation is provided for an integral analysis of regional exploration by using oil-bearing system. Basic geologic conditions in F Depression is analyzed, the possible reservoir forming modes are predicted by using the theory of oil-bearing system, direction and target for further exploration are pointed out, by which bases are laid down for improving success ratio and exploration efficiency.