Study On Logging Interpretation And Fluid Identification Of Acidic Vocanic Reservoir In Xujiaweizi Area

With the growing increase in energy demand globally, oil and gas exploration in the igneous rock had been an assignable part. Oil-gas identification in the igneous rock reservoir have already attracted attention from working staff whose occupation dealing with oil both home and abroad, it has already been an important research subject accordingly.The Xushen1 well obtains 1,000,000 cubic high gas production is as the symbal of the discovery of gas reservoir in deep-seated igneous rock of Xujiaweizi area.and to be a new breakthrough in oil-gas exploration of Daqing Oil Field, which is of significant importance to steady output of oil field. Meanwhile, in terms of comprehensive evaluation and analysis of igneous rock reservoir, working staff whose occupation dealing with oil are now facing the challenge. The previous interpretation and evaluation technology directed at the clastic rock reservoir aims at the matrix porosity ,is not applicable to double porosity system of igneous rock reservoir.As for the research both home and abroad, former Soviet Union, US, Libya, Venezuela and and our country's Bohai Gulf, Erlian of Inner Mongolia, Zhunger, Talimu, Jiangsu and so on places , the discovered igneous rock reservoir is mainly oil-producing, lithology is medium-basic in majority. The Nangang gas reservoir is rhyolite gas reservoir, Schlumber undertakes the acquisition of wireline logging ,but for the limits of technological development, only conventional programs of CSU system are acquisited, the data acquired is limited and is far away for evaluating the reservoir elaborately. Therefore, to improve the study of logging interpretation technology of igneous rock so as to meet the needs of oil field exploration had been the first thing .The geology condition of Songliao Basin is complex. Most of the igneous reservoir's thickness is more than 100meters,and the depth is usually more than 3,500 meters.The main characteristics namely the difficulties are as follows: The lithology is complex, including igneous rock,athrogenic rock and also transition rock. The type of acmulating is complex, not only porosity but also fractures and caves . The deep-seated igneous rock reservoir of Xujiaweizi area belongs to low porosity-permeability reservoir with high anisotropy. There are many problems in logging interpretation, especially in measurement and analysis of lab rock resistivity relations of igneous rock, study on electric conduction mechanism of igneous rock, the establishment of saturation model for igneous rock when fluid is gas and water, fluid identification in diplopore medium of igneous rocks. The paper is directed towards many difficult problems occurred in diplopore medium of igneous rocks, seize the chance of acceleration of oil exploration and development in deep level, notable increase of varies kinds of logging data and other interrelated business data. On the basis of laboratory investigation, comprehensive interpretation and evaluation study combined with conventional logging technology, microresistivity scanner, NMR imaging logging technology had been carried out, which had lay a foundation for logging interpretation improvement.1. Based on the rock analysis data, the matrix parameter of acid igneous rock is derived from cross plot technology, the matrix porosity and permeability evaluation method of conventional data and nuclear magnetic data in igneous rock reservoir is established.The absolute error of calculative porosity is less than 1.5%, the calculative permeability can keep the error within same quantity degree.Based on the microfracture modeling well data, established the evaluation method of fracture parameter, ensure the relation between the true fracture parameter and the logging image.Improve the accuracy of image logging interpretation.According to the results of computing we can see that all the computed fracture width are bigger than the true fracture width. For the fractures of 1.5mm and 2.0mm,the the calculated resultes are close the true data,but for the 0.6mm and 0.2mm fractures, the repeatability and relative error are big.2. Many application already proved that Archie formula is not applicable to complex lithology. In order to study the conductive mechanism of acidic igneous rock reservoir, proceeding full diameter core petrophysics experiment.Comparing and analyzing the double porosity system saturation equation of Xinjiang Kelamayi oil field and Jilin university and Schulumberger. According to the truth that fluid property of deep igneous rock reservoir is gas-water in Xujiaweizi region in Songliao Basin, the dynamic saturation theory varying with porosity is put forward, and the corresponding interpretation model and the applicable saturation equation is established. 3. In the igneous rock reservoir before, the lithology has great effect on the log response, fluid response is weak, and the resistivity in identifying fluid property underplays. According to the truth that fluid property of deep igneous rock reservoir is gas-water in Xujiaweizi region in Songliao Basin, the combined identify method of fluid property of conventional, nuclear magnetic, XMAC data in igneous rock reservoir is established, the fluid property identify technology is enhanced and the interpretation coincidence rate is improved. A suite of well logging interpretation method appropriate for the igneous rock reservoir of Xujiaweizi region in Songliao Basin is introduced. The reservoir parameter computation precision and fluid property identify precision are all improved. These made the well logging interpretation of igneous rock play an active role in the deep gas exploration.