Geochemical Logging Evaluating Methods And Its Applying Research Of Low Permeability Reservoir In Changqing Prospect Area

In recent years, with the petroleum resource becoming increasingly tense, the domain of petroleum exploration and exploitation has been continuously expanded and extended. At the same time, the exploration targets have become more complex, the technical difficulty of the discovery of new oil (gas) reservoir (field) is also growing. Low permeability oil and gas resources found in the oil and gas resources as the proportion has increased year by year. Low permeability lithology reservoir (Field) has strong concealed, not typical four of the relationship, more complex oil and water relationships features, the use of conventional geological logging, logging and other technology tools in the discovery and evaluation of low permeability reservoir ( possession) often encountered some technical difficulties.Geochemical logging technology is a technology with the organic geochemistry detection technology development and improvement, combined with the oil and gas exploration and production technology needs, some people will be able to quickly detect reservoir the testing technology used in oil and gas drilling with logging work, and gradually develop and improve the technology of a quarry path in the 20th century to the late 1980s and early 1990s. The geochemical logging technology include many test technology which are used in oil quantitative and qualitative such as the reservoir rock pyrolysis, gas chromatography, fluorescence quantitative, UV, IR, and so on. And the characteristics of the geochemical logging technology is fast direct access to hydrocarbon reservoir rocks contained in the volume and composition of the exact nature of the information, thus, not rock, rock - relations, the impact of factors such as the accurate found and identification of low permeability reservoir (possession), with its own technological superiority.The long-term exploration practice revealed that the Ordos Basin Reservoir extension of a typical low permeability, ultra-low permeability characteristics, and makes low single well production, development difficulties and therefore find the relative quality reservoir hypertonic (fields) as oil exploration priorities and difficulties. At the same time, the major group of low permeability reservoir, causing low-permeability characteristics: (1) reservoir lithology is the most important reservoir type, the greater the hidden nature; (2) reservoir heterogeneity of the strong, Seepage of the reservoir capacity significantly, (3) changes in the oil water heterosexual large (4) of the oil reservoir and the relationship between a typical uncertainty of oil low resistivity and high water blocking layer (testing), (5) zone between the group and reservoir wettability of the reservoir there are differences of similar oil reservoir, the oil test results to vary (6) as the low permeability reservoir is generally very low pressure reservoir vulnerable to pollution, drilling in the process of formation of natural gas wells to be no significant influx, the gas log shows that lower-class, are many factors interference can not reflect the true reservoir gas content. Because of the above reasons, to greatly increase the quality reservoir accurate identification and rich reservoir of the difficulty of determining the accurate, and so the traditional geologic logging, logging and other identification on the basis of reservoir technology, there is an urgent need to use new identification technology and integrated reservoir identification technology so as to enhance the accuracy of reservoir identification, wildcat Optimization of the test reservoir to provide a scientific basis.In this Paper, we choose the typical low-permeability petroliferous basins - Ordos Basin Jiyuan region as our research area, the application of hot rock pyrolysis and gasification phase chromatography, and other geochemical methods for oil exploration in the oil and gas accurate identification of the technical problems can be optimized Direct detection of reservoir rocks oil volume and composition of the nature of reservoir rock pyrolysis, thermal gasification and gas chromatography, and other technologies as a means of logging, use of a large number of reservoir properties, the formation of high-pressure oil and crude oil all hydrocarbon chromatography, reservoir rocks Gas Chromatographic Analysis of hydrocarbon residue on the basis of information to determine the oil reservoir rocks level interpretation of the parameters established for the study area oil reservoir level interpretation methods, standards and maps, and through trial and the results of comparative analysis oil , confirmed its accuracy and effectiveness. Its good trial results, especially in the low resistivity and high water blocking formation of accurate identification, such as a show of superiority in technology, the technology has demonstrated a good promotion prospects.The paper in resolving the Ordos Basin in low permeability reservoirs of oil and oil accurately identify technical problems that logging has made the following main innovation of progress:1. Reservoir rock cuttings pyrolysis - Gas Chromatographic Analysis of available hydrocarbon Chromatogram thermal evaporation, can be used for accurate identification of reservoir oil or not, oil reservoir discrimination generally, as well as the authenticity of oil and gas shows. A lot of testing data shows that, in Jiyuan region, different areas of the oil reservoir rock hydrocarbon Chromatogram thermal evaporation is very similar to n-alkanes mainly distributed in the C12 to C34 between isoparaffin, heterocyclic paraffin content low. Therefore, the technology should be focused on the oil and gas shows in the qualitative identification.2. Through crude oil chromatographic analysis and reservoir rocks rapid chromatographic analysis of the spectra compared, we determine the thermal analysis of the samples before processing nC12loss of the group, calculated in accordance with reservoir rock pyrolysis total hydrocarbon recovery factor of 1.4.3. According to oil saturation and reservoir rock pyrolysis of hydrocarbons relations theory, the adoption of test results and oil and logging parameters of the comparison and analysis, and taking into account reservoir characteristics, sub-regional and determined the fuel reservoir, the water layer identification standard and theoretical chart.4. We apply this technology to explain the Jiyuan region Yan'an group and Yanchang group 27th-storey, compared to the results of the test oil one in 21 of the conclusions and interpretation of logging test results in line with oil, and not in line with a six-storey, the congruous rate is 78%, significantly increased levels of logging comprehensive interpretation, and solve the identify problem s of low permeability reservoir evaluation of oil-water layer.5. Solve the problems of low resistivity reservoir identification. Oil and gas reservoirs low resistivity layer resistivity of less than or close to the same geological conditions in the region under the water layer resistivity, high salinity in the region is even lower than rock resistivity. Low resistivity reservoir accurate identification is the difficulty of logging technology. Through rock pyrolysis parameter analysis, gas chromatography analysis, oil reservoir in nature, the establishment of low resistivity reservoir, the reservoir was oxidized to explain methods of logging. Geng132 wells on the technical analysis of log interpretation, reservoir found a layer of low resistivity, made Chang2 layer the oil-producing 10 t/d the outcome of the formation of low resistivity timely detection and accurate identification is of great significance.In a word, the research object of this paper is the technical problems we encountered in actual exploration and production, petroleum geology study area characteristics of understanding, test methods, the establishment of a representative of several complex evaluation of oil-water model to study papers District petroleum geological characteristics of knowledge-based, seize the reservoir rock pyrolysis, gasification phase chromatography and thermal logging data interpretation of this critical link, through means test to determine the parameters of the explanations, which has established a representative Several of the complex evaluation of oil-water layer model, the composite conventional logging, laboratory analysis, logging, test data and other oil comprehensive explanation, see the application in the production of good results and solve the current exploration and development constraints wellbore evaluation of development Evaluation of the water problem; its interpretation of evaluation findings for the development of the perforation programme reasonable judgement oil fracturing test results provide a reliable basis to reduce exploration risk and enhance the efficiency of exploration, from a qualitative interpretation of the quantitative evaluation leap. The paper has important signification in both technical practices and the academic theory, at the same time, the development and application of the new geologic logging technology of new technology must be closely integrated with the geological and academic thinking has also been embodied better.