| The Wuliyasitai sag,which is located in the manite depression of the northeast of Erlian basin,is characterized by multi-source,near-source,coarse clastic and fast phase change and divided into three trough zones: northern sag,middle sag and southern sag from the north to the south.Most of the previous studies focus on the regional geological characteristics or some aspect of the southern sag.However,the in-depth analysis and comprehensive study of the single reservoir in the middle and northern sag are rare,and the comprehensive study of the important geological characteristics in the region is even less.The stratigraphic division used in H area which is one of the main oil and gas producing areas in the middle and northern sag is not consistent with that of the south of Wuliyasitai sag and adjacent depressions and the interpretation of the structural system is unreasonable,which lead to the great difference between the exploration,development plan and the actual drilling,and water injection effectiveness.The key problems to be solved in the study area are what is the situation of the stratigraphic division and correlation are,what is influence of the tectonic assemblage and sedimentary facies type on the hydrocarbon accumulation,what is the hydrocarbon accumulation model,what is the prospect of the exploration prospect,what development adjustment measures are formulated,and so on.Therefore,it is necessary to study the geological characteristics of this area.On the basis of the collected a large number of data and predecessors' research results,I have studied formation characteristics,tectonic characteristics,sedimentary micro equal geological characteristics of H area,and have established prediction model and the three-dimensional geological model of the purpose layer reservoir of major oil-producing areas,guided by the theoretical knowledge of sequence stratigraphy,structural geology,geophysical exploration,sedimentology.The structural characteristics of the controlled hydrocarbon accumulation in this area are studied,the tectonic evolution process is discussed,and the main hydrocarbon accumulation patterns and the transverse and longitudinal distribution characteristics of the remaining oil are summarized.Finally,the reserves replacement block is found by using the comprehensive research results of geological characteristics,and the comprehensive adjustment measures of the main producing area block are optimized.The main work of this paper focuses on the following aspects:1.High resolution sequence stratigraphy and well seismic method are applied to seismic,drilling and well logging data to conduct fine stratigraphic division and correlation study of H area.The research results show that the oil reservoir,which previous generalize into the first of Tengger,issubdivided the oil reservoir group into five oil reservoir groups,including the first of Tengger section,AI+AII section,AIII section and AIV section.2.In this study,multiple seismic interpretation methods,such as automatic horizon tracking,multi-line joint interpretation and three-dimensional display,were adopted to complete the structural interpretation of the study area from point-line-surface.The fault distribution characteristics in plane could be divided into four groups,and there were many combination styles on the section,forming a variety of structural traps such as cross fault blocks and complex fault blocks.Since in the early cretaceous,the sag has experienced four stages: rapid subsidence,stable subsidence,return and extinction.3.Based on reservoir petrological characteristics,sedimentary structure,particle size characteristics,and logging facies research,it is comprehensively judged that there are two types of lake and fan delta sedimentary facies developed in Tengger formation and Aershan formation of H area.A ?period of deposit underwent two lake retreats and two lakes advance,and formed two sets of thick reservoir,which are A?4 and A?2.The depositional sub facies of Tengger formation is dominated by lake phase,which have the most important hydrocarbon source rock and regional cap layer in the study area.4.The dominant attributes of the Tengger and Aershan formation oil formation,including instantaneous frequency and root mean square,were extracted.On the basis of seismic attributes and well logging data,the reservoir prediction model is established using a sparse pulse inversion method in the study area.The information of sedimentary microfacies,sand body distribution and hydrocarbon accumulation area could be obtained from the reservoir prediction model.Finally on the basis of above results I summarized four major reservoirs in the study area of oil and gas accumulation patterns,and the lateral pinch-out tectonic lithologic accumulation model of upper storage sand body of lower hydrocarbon generation of A?1 sand group got breakthrough.5.On the basis of the previous comprehensive geological characteristics research,the modeling software is used to make the geological characteristics three-dimensional visualization.The lithofacies model,porosity,permeability,oil saturation and other attribute models of the study area are established.The remaining oil distribution in the study area is obtained by numerical simulation of a three-dimensional geological model combined with production data.6.The combined application of the reservoir prediction model and the three-dimensional geological model could make the three-dimensional visualization of geological characteristics,and make the geological understanding of the study area more comprehensive and thorough.Combining the previous results of geological characteristics with the actual production situation,the reserves replacement blocks is searched,and the measures and adjustment scheme of enhanced oil recovery is completed in H area.H area is a typical complex fault block oil field with low porosity and low permeability.The comprehensive research method of geological characteristics such as high-resolution stratigraphic division and correlation,reservoir prediction and facies control modeling used in this paper can be extended to similar oil fields. |
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