Logging Evaluation Method Study Of Complex Reservoir In Baiyinchagan Sag Xilinhaolai Region

For the complex reservoir, its complex geological background led to the electricity standard chaos of oil and gas formation and water formation, and high resistivity water layer and low resistivity reservoir coexist with the normal water layer and oil and gas layer. And the oil and gas formation resistivity is close to the adjacent water layer, even lower than the shale resistivity phenomenon, so the hydrocarbon logging interpretation is extremely difficult.Baiyinchagan Depression has abundant sediment sources , rapid changes in sedimentary facies, and strong reservoir heterogeneity in lithology and pore structure , at the same time, fracture development, oil and water relationships are very complex, high-resistance gas layer, low resistivity oil and gas layer, high resistivity water layer coexist, presenting a variety of types of characteristics of hydrocarbon reservoirs. The Xilinhaolai region within the depression has a conventional oil and gas layer resistivity of 4~10? ? m, while most oil and gas layer resistivity was only 2~4? ? m. The reservoirs resistivity reservoir, so-called low-resistivity, has small differences with the water layer and rock and has certain identify difficulties, so the low-resistivity reservoir evaluation is the focus of oil and gas exploration in Baiyinchagan depression Xilinhaolai region. This paper, aims at Baiyinchagan depression Xilinhaolai region Tengger group, comprehensively analyzed the geological, drilling, coring, logging and test oil to test-drill, etc. and in-depth launched a complex reservoir log interpretation evaluation method.Through extensive analysis of complex reservoir characteristics, starting on the geological background, rock physics and logging information to study the low resistivity mechanism of complex reservoirs in Baiyinchagan depression Xilinhaolai region. Figure that the low-amplitude structures is the main geological background leading to the entire oil and gas reservoirs with low resistivity, while the complex pore structure, a high irreducible water saturation, clay additional conductive layers caused by the complex lithology also improve the conductivity of oil and gas, reducing the oil and gas layer and water layer contrast, high salinity formation water also makes the reservoir of well-developed conductive network lower resistivity, the development of the thin interbedded sand-shale to further reduce the electrical resistivity log response to the formation of the sensitivity, the conductive minerals such as iron pyrite also greatly influences the characteristics of resistivity curves, the cross-combination of these factors makes the area more subtle characteristics of reservoir, thus increasing the difficulty of identifying oil and gas layers.For the strong heterogeneity features of the complex reservoir, inducted the flow unit and classified the reservoir for three types, then calculated the permeability separately. The flow zone target can reflect the reservoir lithology, physical properties and the pore structure characteristics, and the established penetration rate model improves accuracy than the past conventional model.Baiyinchagan Depression complex lithology and physical properties result in the wide range distribution of Archie's parameters, separately studying the relationship between porosity and saturation index with the clay content, pore structure, particle size index and the porosity, then established m, n value models by the variable porosity and seeked for the formation water saturation applying the variable-parameter method to. This method improved the Archie parameters of selection and improved the water saturation model accuracy.Pointing at the problem that Xilinhaolai region oil-water layers are difficult to recognize, on the premise that only having conventional logging suite, through a comprehensive analysis of logging and oil production test data, integrated extracted the conventional logging information which have strong sensitivity, using multi - parameters of cross-combination, basing on the crossplot technique, established the oil-water layer recognition plates, considering the influence of the lithology, physical properties and water properties and other factors, amplified the tiny differences between oil and water to enhance oil and gas layer identification accuracy, and for the further exploration and development of Baiyinchagan Depression Xilinhaolai region provides a favorable technical support.