Logging Evaluation Of Buried Hill Reservoir In Archaean Metamorphic Rock Of Xinglongtai Area

Although with many years of exploration in buried hill zone of Xinglongtai area, there are still a number of problems needed to be studied intensively. On the basis of large amounts of detailed work, with relatively mature newly-developed techniques,theories and methods on buried hill, petroleum geology of low buried hill is recognized and summarized again from comprehensive and unique perspectives in order to develop a series of exploration technique with characteristics of Liaohe Oilfield. This paper focuses on key factors of hydrocarbon accumulation in inner buried hill. According to practical exploration situation, with regard to complexity of lithology, indistinctness of fracture development and difficulty in effective reservoir identification, in-depth research is proceeded with emphases. Following results are obtained:Geologic characteristics of buried hill reservoir are studied using data of seismism, geology, testing and analysis etc. Emphasis is put on establishing standards and models for lithology discrimination, reservoir identification, fracture characteristics and parameter interpretation for buried hill in Xinglongtai area to determine various parameters such as net pay thickness and effective porosity etc for calculating reserves.According to comprehensive geologic characteristics of Xinglongtai buried hill zone, Archaean buried hill reservoir is mainly composed of biotite plagioclase gneiss, containing migmatitic granite and intermediate acidity igneous rock. Reservoir space mainly consists of disrupted pore, macrostructure and microstructure fractures. Reservoir rock exhibits medium low-low permeability.Starting with log response mechanism in the study for Archaean buried hill rock, principal petrogenetic minerals are identified based on thin section and X-diffraction bulk-rock analysis. According to differences in characteristic logging values of various petrogenetic minerals, gamma ray, density, neutron and photoelectric cross-section index logs are adopted as the main way of lithology discrimination. Qualitative identification method for Archaean lithology and quantitative division standard for reservoir rock are established. And relatively good result is obtainedOn the basis of the five principal petrogenetic minerals (quartz, potassic feldspar, plagioclase, blotite and amphibole) of Archaean buried hill rock determined by thin-section and X-diffraction bulk-rock analysis as well as density, neutron and moveout logs sensitive to lithology and reservoir, main log characteristics for lithology discrimination are formulated. Processing and interpretation of imaging log data for this area are completed. The method for fracture evaluation and effective thickness division is developed using conventional and acoustoelectric imaging logs. This lays a solid foundation for comprehensive evaluation of reservoir...