Characteristics Of Reservoir Reservoirs And Reservoir Three - Dimensional Modeling Of Chang 2 Reservoir In Yeyue Oilfield, Hengshan Oilfield

Bai LangCheng oilfield is overall located in northeast Ordos Basin near the provenance, which currently is the demonstration zone of water flooding development throughout Yanchang oilfield, even the whole basin. In the early stage, the yield was not high due to influences of technology, environment, and human factors when it was exploited depending on the natural energy. Because of the good coordination of every condition---formation, reservoir, cap, entrapment, transport, preservation, in the study area and being affected by geographical conditions, the yield of Chang 2 reservoir has achieved a quick breakthrough when water was injected. However, at present, it has not been well studied on how the reservoir forming conditions is matched to the depositional facies and the reservoir in the study area.Years of exploration results illustrates that Bai langcheng gets breakthrough in oil and gas enrichment, with good conditions for accumulating in local areas and controlling a large area of oil-bearing, which has become the main areas of development and production in Hengshan Oil Extraction factory in recent years. But with the decrease of water flooding effect in late stage, Chang 2 reservoir is faced with many problems:the sandstone reservoir, varying quickly in lateral orientation, belongs to the reservoir of low porosity and low permeability. The oil reservoir contains much water, primary oil production generally with higher water content but decreasing rapidly.This paper takes multi disciplines as theoretical guidance, and 300 wells are analyzed one by one in this study area, combined with quantities of data of well-logging, logging, laboratory analysis etc. It is studied from the stratum to tectonic, sedimentary facies and reservoir. Finally, analyzing the relationship between hydrocarbon reservoir and various geological conditions stated above, and building three-dimensional geological model of this study area, provides the geological basis for the subsequent development of the oilfield.The structure of this area is relatively flat, with a small fault in the southeast and developing good oil-gas on both sides of the fault. At the same time, the structure also has obvious controlling effect on oil-gas which is produced more in higher position than that of the lower structure.Chang 2 sediments are mainly deposited on the water of Ansai Delta, generally developing delta front subfacies. The channel sand microfacies account for more than 90% of the whole study area and alluvial flat microfacies,can seen only in a small area, distributes as dots.Meanwhile, the study of the reservoir has been conducted in detail mainly from both the macro and micro aspects. Macro aspect is performed in the distribution of sand and sedimentary facies. And micro aspect of the study is to analyze the characteristics of the reservoir rock, pore structure, diagenesis, pore type and petrophysical properties by means of the analytic experiments in laboratory, in order to classify the Chang 2 reservoir according to classification criteria. There is mainly feldspathic sandstone in the study areas and the sandstone has well pore structure with macroporous and fine roar type; compaction throughout the various stages of diagenesis, and the characteristics of diagenetic dissolution and cementation clearly seen in the microscope; the pores mainly residual intergranular and corrosional types. Hence this can be determined into a class Ⅱ reservoir with better petrophysical properties.The Bailangcheng oil reservoir is mainly affected by river sands, caprocks, entrapment and diagenesis. While the reservoir forming conditions of the study area in all aspects are speculated reasonable in accordance with the characteristics of the crude oil, formation water and water flooding experiments. Therefore, the overall reservoir is contiguous on the plane and has a sheet-like distribution. On the longitudinal direction the reservoir is well connective due to the connectivity of sands. And this is a reasonable geologic setting for later development of water injection.Tectonic, sedimentary, reservoir and oil reservoir research were to provide geological basis for three dimensional geological modeling. The completion of structure, sedimentary, interlayer insulation, geological properties (permeability) modeling in the constraint of phase and reservoir, according to the model reflects the remaining oil distribution in the study area, and summarize the causes, mainly with small well spacing density, injection-production imperfect, reservoir itself factors. On this basis, the phenomenon of the remaining oil distribution in the study area is put forward for the adjustment of the structure of well pattern, injection-production, measures, and pay attention to the development of high efficient Wells.