| Caoqiao buried hill tectonic belt is located in the territory of Daying township, Guangrao county, Dongying city, Shandong province, the reservoir of is shallow, the depth of 520-840m into the mountains. The crude oil of high density, high viscosity, high viscous oil, oil density of 0.98 g/cm3 or more, the viscosity 28500-65000mPa-s, reservoir type belong to carbonate rock of porosity fracture-dissolution composite reservoir. Influenced by strata, lithology, structure and other factors, the reservoir distribution, oil water distribution, reservoir property and so on are complex and changeable. Based on the geological data obtained from the exploration, the reservoir fine description, research, evaluation and understanding of the characteristics of buried hill comprehensive geological data can effectively guide the exploration and development of this area.In this paper, Caoqiao buried hill with Caogu 1 buried hill, Guangqi 2 buried hill and Caogu 125 buried hill as the focus, based on seismic, drilling, logging, coring, logging, well testing and test data of oil production and so on, the reference for similar reservoir research, reveals the formation development characteristics and structural features of buried hill; study the Ordovician carbonate rock porosity-fractured reservoir development characteristics and the type of reservoir space; identify favorable reservoir facies and of the reservoir have been classified; evaluation of oil test capacity and fluid properties; clarify the relationship between oil and water, reservoir type and temperature-pressure systems; analysis of the reservoir structure, lithology, reservoir development and distribution, cap rock and other factors. Get a lot of new understanding1. Caoqiao buried hill formation are composed of Ordovician and Cambrian and pre Sinian. The Ordovician strata by Yeli-Liangjiashan formation, Lower Majiagou formation, Upper Majiagou formation and Badou formation of limestone, marl, dolomite and other typical characteristics of regional composition.2. The overall structure of Caoqiao buried hill is the North South high-low large slope feature and its form is "one saddle and two ancient gully, three ridges". Caogu 1 hill, Guangqi 2 hill, Caogu 125 hill etc. are South East North West High low trend, largely from the 1-5 residual hill form. The study area has more than 50 normal faults, mainly to the North West, North East, NNW and NNE trending.3. Reservoir properties of reservoir depends primarily on weathering shell holes, cavities and fractures development degree. Its reservoir has the following characteristics:(1) The reservoir space has a variety of types; (2) Fracture characteristics exhibited regularly buried the western part of the Ordovician carbonate rock reservoirs crack the most development; (3) The Ordovician weathered crust in buried hill is the most favorable reservoir facies.4. Ordovician reservoir buried relatively shallow, the formation of the top cover is weak, crude oil suffering oxidation becomes heavy, due to the different burial depths, there are some differences in different parts of the crude nature of the hill. At 50 ℃ oil viscosity has obvious variation in the plane distribution, southeastern, central well area the largest oil viscosity, increasing the depth of the reservoir to the northwest, oil density and viscosity decreases.5. Caoqiao buried hill as the normal formation pressure of high temperature abnormal oil water system, the distribution of oil and water can be divided into three well area, there are some differences in oil and water systems in each well area, according to the depth of the reservoir, Oil-water boundary between 595-710m.6. The degree of oil accumulation in Caoqiao buried hill oil reservoir is mainly controlled by factors such as structure, lithology, the development degree ofhole and seam of weathering crust, reservoir distribution and cap rock condition. |
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