| This specification is set for the theses of Chengdu University of Technology. The Tarim Basin is the largest inland superimposed basin which enriches oil and gas resources in China. Oil and gas exploration in the basin has experienced almost50years, and we have made a series of significant breakthroughs in Tazhong, Tabei, Bachu, Kuche and other areas, and have found the largest marine carbonate oil field, marine sandstone oil field and continental high pressure gas field in our country. In recent years, CNPC and Sinopec attaches great importance to marine oil and gas exploration in the Tarim Basin, especially to research of oil and gas accumulation in Lower Paleozoic marine carbonate rocks. The discoveries of Lower Paleozoic oil and gas fields in Lunnan, Tahe and Tazhong areas indicate the great prospects of oil and gas exploration in marine carbonate rocks.The carbonate reservoir evaluation is a world problem in the process of oil and gas exploration and development. Carbonate fractured reservoirs have extremely complex pore space structure and strong anisotropy, which also has been a huge problem troubling logging interpretation workers, especially in the fluid properties that has relatively low interpretation accuracy. Some seemingly good reservoirs are water layers after actual testing, and some logging display poor reservoirs are productive oil layers after acid fracturing. As most of the logging instruments and logging methods are for homogeneous strata, and there is not a perfect logging evaluation method for carbonate fractured reservoir, we make further analysis and research on carbonate reservoir in this thesis based on all the above issues and previous studies, and the main achievements are as follows:1, Vertical and horizontal contrast analysis of logging information in Tazhong area reveals that oil and gas shows mainly concentrate in Carboniferous Bachu formation, Devonian Donghetang formation, Silurian Kepingtage formation, Ordovician Lianglitage and Yingshan formations in the vertical, among which Yingshan formation has the most frequent oil and gas shows; there are better oil and gas shows in Kal area and Shuntuoguole area in the plane.2, In the vertical multiple sets of reservoirs are developed in Tianshannan area, and have many gas shows in drilling which are mainly concentrated in the Bashijiqike formation, ShuShanRiver formation of Cretaceous and Lower Tertiary KumuGeliemu formation. Seen from logging interpretation of each set of reservoir, reservoir physical properties of Bashijiqike formation, Suweiyi formation, and KumuGeliemu formation are relatively good, and Yageliemu formation has the worst physical property because of less drilled wells and complex rock composition.3, According to the analysis of four characters of reservoir:properties and relationship of porosity and permeability in Carboniferous and Devonian Donghe sandstone in Tazhong area are relatively good, and that of Devonian and Ordovician are worse. Fine-grained sandstones are main reservoir lithology in clastic rocks, and limestone and dolomite are likely to become reservoirs in carbonate strata; reservoir properties from Cretaceous Suweiyi formation to Kapushaliangqun formation are relatively good in Tianshannan area, which are mainly low porosity and permeability, and reservoir type is pore space reservoir distributed in the medium-thin sandstone. Since that lithology is one of the main control factors of the property of oiliness, and different lithologys have different properties of oiliness, fine-grained sandstone has the best properties of physic and oiliness, that of muddy siltstone and conglomerate are the worst; there are some relationship between reservoir properties of physic and oiliness, the better the physical properties, the better the oil and gas shows of reservoirs; with increased hydrocarbon saturation, the resistivity rises.4, We adopt this method to identify the reservoirs of clastic rocks in Tianshannan area:first identify sandstone (conglomerate), then search for pore growth section in sandstone (conglomerate), and determine the reservoir electrical minimum:GR <90API; AC≤67μs/ft; CNL≥9%.5, According to geological studies and core observation, we believe that reservoir types of Ordovician reef-bank in Tazhong area can be divided into:Vuggy type, fractured type, Fractured-Vuggy type and cavernous type.We Systematicly summarize the geological features and logging response characteristics of these several types of reservoirs, establish the corresponding identification standards, research on the effectiveness evaluation method of Vuggy and cavernous reservoir, and put forwards identification methods of filling and filling degree of vug and caves.6, We establish a series of methods to identify fluid properties, such as absolute value of resistivity discriminate method, porosity and water saturation intersection method, bound water saturation and water saturation overlapping method, resistivity and porosity intersection method, three porosity overlapping method and so on for Tianshannan clastic rocks; and explore to establish classification fluid properties discrimination plates, the resistivity index fluid identification plates and water resistivity distribution of imaging logging apparent formation fluid properties identification technology for carbonate rocks in Tazhong area.7, On the basis of research on four characters of reservoir, we establish logging reservoir parameters calculation model of permeability, saturation, lithology, and fracture porosity in Tazhong area and Tianshannan area with division of blocks, formations and reservoir types. Processed reservoir parameters have good correlation with core analysis data, which confirms that the model of the reservoir parameters can meet with the computing requirements in this district.8, We summarize Ordovician fracture types and imaging characteristics of Tazhong area, analysis the effectiveness of fracture discrimination and make vertical and horizonal contrast analysis of fractures in Kal area and Shuntuoguole area according to interpretation results of the FMI fractures, and results show that: fractures in Kal area are mainly developed in the Yingshan formation and the upper Lianglitage formation in the vertical, and the development degree of fractures in Zhong18, Zhong19well area is poorer. Fractures of Shun2well in Shuntuoguole area near Tazhong No.1fault are most developed, that of Shun6well are secondary, and that of Shun4well are worst because of its smooth structure. The lateral changes of the fracture trend of all wells are so big that fractures can be divided into single direction, double direction and multi-trends. Analysis from fractures trend and tectonic line, fracture trends of part of the wells, such as Tazhong86, Tazhong85, Tazhong66, Zhonggul, Gulong1, Zhong2, Zhongl6and so on, are more consistent with structure line, which explains that stress of present structure and the ancient structure has some similarity.9, Analysis of relationship between FMI fracture strike and the direction of maximum principal stress in Tazhong area shows that the stress orientation in this area is NE-SW in general, but that of Zhong4, Zhong41in Ka4area becomes NW-SE, and that of near Gulongl is approximately by East form North to South, and approximate to orientation of the large fault near the well. The direction of the stress orientation and FMI fractures are overall consitent, which shows that at present stress direction is propitious to fracture growth, while there is a larger angle between fracture strike and stress orientation in Zhong2and Zhong17, and it is not conducive to fracture growth.This thesis researches from the actual data, based on theoretical analysis, laboratory data analysis and actual logging data research, establishes a pore-fracture-cave reservoir logging evaluation methods, which are applied and validated in several Tarim oil and gas fields, and receives significant effect. Therefore, the research results not only have strong theoretical significance, but also have important practical value. |
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