The Study Of Geological Modeling Of Chang-8-1 Reservoir In Heshui Block, Xi'feng Oilfield

Building a quantitative geological model that can reflect the reservoir geologic characters and scales is the core and purpose of modern reservoir description, the key of reservoir simulation and dynamic prediction, also the base of knowing the reservoir objectively and truthfully and developing the reservoir efficiently and accurately.The paper focuses on the fine geological modeling, and takes the Heshui block Chang-8-1 reservoir in Xi'feng oilfield as an example, using different theories and techniques of many subjects including sedimentary, sequence stratigraphy, petroleum geology, development geology, reservoir engineering and so on. Aiming at the reservoir geological character, on the base of basic geological study, it sets up the 3D geological modeling of the Heshui Chang-8-1 reservoir. The model shows the underground geological characters objectively, correctly and externally, reveals the concentration rules of oil and gas, and settles the base of developing this reservoir efficiently and accurately. And some outcomes have been achieved based on this study.1. Under the guidance of traditional method of"correlating according to sedimentary and geological hierarchy control", about 94 wells in work area have been correlated referring to the control of marker bed, so the Chang-8-1 is divided four substratums.2. Based on the core observation, according to lithology, physical property, and sedimentary structure, depositional sequence, areal distribution feature of sand body and the character of well logs, the sedimentary facies in work area is identified as braided river delta front subfacies, and four kinds of microfacies are recognized: distributary channel, mouth bar, distal bar and interdistributary area.3. The study on reservoir shows that the reservoir in the work area has the pore structure characters of small pore and small throat, represents low porosity and low permeability, and has two kinds of interlayer including shale interlayer and calcareous interlayer, and their electric log curves have different characters.4. The relationship of four properties is set up based on the cores and logging data and the log interpretation model is built, so all wells have been interpreted secondary. Furthermore, the reservoir property and its heterogeneity are studied, and the reservoir is classified three groups by using grey theories, the result shows that I reservoir is the best oil and gas enriched zones.5. By using the reservoir modeling software PETRELTM, the 3D geological model of Heshui block, including structure model, the sedimentary microfacies model, sand body model, property models, and net pay model according to the cutoff value is established and the reserves calculating from 3D model coincides with the result from traditional volumetric method. The geological model becomes the base of reservoir simulation and dynamic prediction in the future.