| With the high-speed development of national economy, the growing demand for oil, while in our country recently proven crude oil reserves, reserves of low permeability reservoirs, the proportion is more and more big; In proven reserves and accumulated have proven reserves and did not use in the low permeability reserves are accounted for the main part. Usually think that the average permeability rate in the10-50MD reservoir generally low permeability reservoir; Penetration in1-1OMD for ultra-low permeability reservoir; permeability of less than1md ultra-low permeability reservoirs. At present, the gas injection as a kind of effective method to improve recovery efficiency, is widely used throughout the world. Gas injection technology is very mature in the United States and Canada. In the United States, the gas injection project is given priority to with carbon dioxide miscible flooding, while Canada dominated by injecting hydrocarbon solvent miscible flooding. Gas injection technology in China development speed is slow, but also to carry out a large amount of gas drive in recent decades the indoor experimental research and field pilot test. In the1990s, the United States alone,292oil field oil-producing areas using CO2flooding, EOR7%to15%, to prove that CO2flooding is the EOR one of the most potential in the tertiary oil recovery.70-80’s CO2flooding technology has been greatly developed, the United States and other countries have carried out a lot of CO2flooding industrial test and achieved remarkable economic, Recovery efficiency can be increased by15%～25%. Industrial emissions of carbon dioxide for enhanced oil recovery is a promising vision. In this paper, the huang field qian43oil group Note CO2enhance oil recovery research, Study qian43reservoir geological characteristics, sedimentary characteristics and formation fluid phase behavior, as well as the injected gas and formation fluid miscible pressure, On the basis of combining with reservoir numerical simulation study qian4oilfield development plan。huang field Oilfield is located in Qianjiang Depression eastern slope of regional sandstone pinch-out to bring, Qian43oil group structure is simple, Composed of long-term development of the ancient monoclinic structure, east slowly west steep, to close to the north and south, stratum from west to east high, sandstone pinchout along up direction. Constructs were cut fault zone in the south,the region huang40wells are also located nearby a small fault zone, substantially parallel to the fault zone; structure North daihe Oilfield connected, fault complex structure, Tectonic break, mainly lithology and structure of lithologic reservoir. huang field Oilfield longitudinal direction of the oil layer is more top-down qian31, qian41, qian41under, qian40、qian42、 qian43oil group, which Qian43oil group on the vertical, the distribution most extensive, the largest reserves, reserves accounted for52.8%of the oil field. This article main research is as follows:first, in the huang field43oilfield on the basis of reservoir data, the reservoir geological characteristics, sedimentary characteristics, formation physical properties, reservoir properties and fluid properties analysis and evaluation; Secondly, based on reservoir fluid PVT experimental data, application PVTi phase state simulation software for reservoir fluid saturation pressure and a single flash experiment, constant composition expansion experiments, differential phase degassing experiments fitting, fitting results analysis fluid phase behavior, but also for the follow-up to carry out of CO2injection numerical simulation research and develop the consultation to develop fluid property data. On the basis of reservoir fluid phase behavior simulation, using the empirical formula method, slim tube test simulation method to study the reservoir fluid and the minimum miscibility pressure; On the basis of these studies was carried out on the huang field qian43oil group late CO2gas injection development program, the final design is most suitable for huang field43oil group’s recommended program. The main have the following conclusion:1、Huang field qian43oil group oil layer is thin,Physical property is poor, Oil property is good, insufficient natural energy,Formation full differential pressure, high water salinity oilfield reservoir characteristics,belongs to low permeability lithologic and structural lithologic reservoir.2、comprehensive domestic and foreign research and qian43oil group of parameters, the oil group development should combine gas water alternate way of development in order to improve oil recovery.3、the reservoir fluid components merge, the proposed combination of crude oil physical properties, for the subsequent gas injection flooding with oil reservoir numerical simulation research and development program of the physical parameters of the fluid。4、through the study of the minimum miscibility pressure, can be found qian43oil group in the case of CO2injection reservoir minimum miscibility pressure reached about17.608MPa miscible or near miscible state.5、the CO2injection main technical parameters, including injection rate, injection concentration and the optimum injection-production well spacing, pressure level, time of shut determine, etc.6、the choice of the Injection speed, when the CO2injection rate greater than60t/d, carbon dioxide gas and water alternate drive crude oil extent of the well group relative to the waterflood incremental growth has been slowing, taking into account the origin of supply capacity, considering select Note gas speed to60t/d.7、when injected into the gas-water ratio of1:1to1.25:1better, considering the overall reservoir pressure recovery need to select the select the gas-water ratio of1.25:1.8、as can be seen from the results, in the process of CO2gas and water alternating injection, with the increase of "injection cycle", the cumulative oil production and produced degree of well group enhancement, after the first oil change rate drops. For40days best injection cycle, so chose the injection cycle is40days.9、Qian43oil group the gas injection recommend embodiment:CO2injection rate for60t/d; injected into the gas-water ratio of1.25:1; Injection cycle for40days。... |
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