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On Interpretation Method Of Complex Oil Zone And Water Zone In Southern Gulong Area

Posted on:2012-11-18Degree:MasterType:Thesis
Country:ChinaCandidate:D X ChenFull Text:PDF
GTID:2120330338955212Subject:Earth Exploration and Information Technology
Abstract/Summary:PDF Full Text Request
With the development of exploration and exploitation in oil field, focus has been turned from reservoirs with good geological conditions and simple oil and water distribution to reservoir with poor geological conditions and relatively complex oil and water distribution. Low resistivity reservoirs have already become focus in exploration and development. Since both low resistivity oil reservoirs and high resistivity water reservoirs are present in Putaohua Formation of southern Golong area, it is difficult to determine oil zone and water zone correctly. Typical core samples are selected from low resistivity oil reservoirs, conventional oil reservoirs and high resistivity water reservoirs, and meseaurements of their porosity and permeability, particle size, mercury, NMR and X-diffraction done. By comparison, it find out that low resistivity of the oil reservoirs are caused by fine-grained lithology, high shale content; high clay-excess conductivity; more microscopic cappillary pore, high irreducible water saturation. High resistivity water reservoirs are caused by residual oil and calcium cement. This provides a theoretical basis for identification and interpretation of low resistivity reservoirs. In this paper, conductive law of reservoirs in Putaohua Formation of southern Golong area is studied detailedly with resistivity measurements of samples in formation temperature and pressure. The result shows that m and n in low oil reservoirs is lower than others. Interpretation models to calculate shale content, porosity, permeability, irreducible water saturation, cation exchange capacity and calcareous conten are established by using experimental data of rock samples and log data. The accuracy of the calculated parameters is high and can meet the needs of quantitative interpretation. Based on the results of genetic mechanism and conductive law achieved in low resistivity oil reservoirs and high resistivity water reservoirs, a new effective medium conductivity model is proposed with symmetrical effective medium conductance theory. Since the model considers capillary bound water conductance, clay excess conductance, free water conductance and the effect of calcium cement on rock conductance, the model is more applicable to interpret low resistivity oil reservoirs caused by high shaliness, high clay excess conductivity, high capillary bound water, or irreducble water saturation, and also applicable to interpret high resistivity water caused by calcarious cement. The program is developed to interpret log data of eight wells, and the results are in good agreement with measured water saturation or production test results. It shows that the proposed interpretation method is suitable for fluid identification and evaluation in Putaohua Formation of southern Golong area.
Keywords/Search Tags:southern Gulong area, low resistivity oil reservoirs and high resistivity water reservoirs, petrophysical experiment, symmetrical effective medium conductance theory, saturation model
PDF Full Text Request
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