Research And Sculpture Of Seismic Attributes On Carbonate Reservoirs In Lunnan Buried-hill

Lunnan area is one of the most important exploration blocks in Tarim oil field, it is also one of the target areas for oil reserves, Lunnan is the research area, and the Ordovician buried-hill is an object. The task uses a lot of seismic attributes(such as coherent,RMS,Perigram data, etc.), and uses geology,well drilling and well logging data to study the characters of buried-hill reserves in Lunnan, to know the statuses of the Ordovician buried-hill fractures tread,the development and types of reservoirs,the connection of fractures and holes and the enclosed oil and gas in reservoirs, and at last, to describe the tops of the "oil units"in detailed, to summarize the control factors of carbonate reservoirs, to forecast the advantaged reservoirs positions and determine the advantaged oil and gas zones in the research areas. It points out the next evaluation and development drilling wells positions, and the achievements of this research is the basis of the oil reserves for Tarim oil field. Lunnan area is a large multi-types oil gathering area, taking Lunnan buried-hill as a integrated karst system, it has different karst zones,different ancient geography environments and different reservoirs rocks, it depends on these different factors, establishes many different traps,reservoirs and oil models to study the karst characters of Ordovician buried-hill, to study the relationships of the advantaged reservoirs and seismic responds, the relationships of the different seismic attributes and oil and gas. There are channels and ridges on the tops of the Ordovician carbonate buried-hill in Lunnan region, and the karst peaks are standing, the channels are crossing, and there are lots of dolinas everywhere, it has the typical karst features, the ancient rivers are inside of the buried-hill, the horizontal underground water systems are up and down, all these constitute the large ancient karst system, it can be contrasted to the modern karst system. The ancient karst highlands and the cavities and fractures systems are the basic units for controlling the oil and gas, the ancient karst highlands can be or not oil and gas reservoirs, it depends on three factors, they are the reservoirs,the covers and the seal conditions of the ancient ridges up-lift; the reservoirs distribute along the ancient karst highlands, and the shape of the reservoirs are irregular, and be controlled by karst cavities and fractures system with the tree branch shape; the whole Lunnan region develop many the ancient karst highlands and the karst cavities and fractures system, the area of the advantaged oil and gas covers 1000Km2 ,forecasting the geological oil and gas reserves 6.5 hundred millions tons. Lunnan is the most advantaged area for oil and gas in Tarim basin, and it is also an actual area. The ancient karst system in Lunnan are majo carbonate reservoirs, the first reservoirs are the karst opertures,caves and underground rivers, the second one are crevices, the reservoirs are very inhomogeneous horizontally. This task uses the advantaged 3D seismic interpretation techniques to describe the distribution characters of the ancient karst cavities and fractures system on plane, to determine the next advantaged oil and gas zones and objects, and to point out the next exploration for development and evaluation on the karst areas. The comprehensive achievements had beenproven and used in Tarim basin oil and gas exploration, more than 50 wells were proposed, 34 wells were accepted by Tarim oil field, among these 34 wells, the ratio of meeting karst reservoirs was 100%, the ratio of meeting oil and gas was more than 80%, the ratio of high oil and gas production was up to 60%, LG15,LG15-1,LG100 and LG100-6 had obtained high industrial oil and gas production, LG15 had 750 tons per day, it was the most high production in Tarim oil field in one day, and it discovered the secret veil of Lunnan buried-hill large-size oil and gas reservoirs, so, this task did a number of contributions for Tarim oil field, it had good benefits in economy and society. This task achievements belong to the comprehensive research results in seismic exploration fields. It first time takes the modern karst theory into the seismic data interpretation, it studies the relationships of the seismic attributes and the karst reservoirs, uses the advanced geophysical processing and interpreting techniques to establish the ancient karst system in Lunnan buried-hill, and to summarize a series of seismic comprehensive interpretation methods for carbonate reservoirs, it acquires many achievements in exploration techniques and comprehensive research work. Lunnan buried-hill has four stages of faults development, middle and early time faults dominate the ancient karst development mostly, the more faults correspond to the ancient eroded channels, and they control the development and dimension of the karst reservoirs, the later time faults dominate the passages mostly, which are for oil and water migrating, these types faults affect the high and stable production wells very much, so, pay more attention to these faults during the selecting the wells positions.The ancient karst reservoirs in Lunnan buried-hill develop along the ancient faults and the ancient rivers system, which distribute with the strip shape, the development dimension of the ancient karst reservoirs concern the ancient faults ,the ancient water currents,the rocks and the ancient karst landforms, to divide the ancient karst system units using the modern karst landforms, to predict the vertical and horizontal development rules of the ancient karst reservoirs, to indicate the oil and gas advantaged zones, and to select the drilling positions using these results. This task study the relationships of the seismic attributes and the carbonate reservoirs, to sculpture the many seismic attributes by 3D seismic visualization technology, to show the Lunnan buried-hill karst reservoirs development rules on the lane and in the space directly; this task first time introduce the "oil units"concept in the seismic data interpretation, to recognize and depict the characters of the "oil units"thoroughly during the research, to know the close relationships of the oil and gas distribution and the "oil units", at present, the "oil units"map is one of the maps which are for determining the drilling positions on the carbonate buried-hill, combining with the seismic attributes sculpture of the carbonate reservoirs, to develop the research of the reservoirs quantitative analysis, and to get satisfactory results. Summarizing and improving the seismic comprehensive interpretation techniques of the carbonate reservoirs-karst seismic interpretation techniques, using the modern karst theory to guide the analysis of the carbonate reservoirs in Lunnan ancient buried-hill, to develop the research of the multi-subjects and a number of seismic attributes, and to provide the completely new technological thinking...