Further Exploitation Of Remainling Oil In Extra-high Water-cut Period

On the strategy of the exploration, most of oil field in china use the methods of water flood. At present,most of oil field in china using waterflood development at high water-cut period.Oil recovery at high water-cut period encountered many troubles such as water production rising greatly, oil production declining, production cost rising, drill or readjust well and development effect deteriorated.Exploitation become difficult at the late stage of oil field development.The pressure and production decline, water cut and degree of reserve recovery is high, and effect of development change into bad at extra high-water cut period. In order to analyze the remainling oil distribution and pull out stimulation of further exploitation,through reservoir engineering and the fine reservoir numerical simulation, some important thinkings and methods of remainling oil distribution were elicited.This text through collecting the materials of geology background, drilling,logging and production,start from studying the single well reservoir, a combined application of reservoir engineering and the fine reservoir numerical simulation is applied to study the distribution of the remaining oil. Through analysing the well pattern and the character of remaining oil distribution, a measurement of further exploitation for oil reservoir at extra-high water-cut period has been put forward and optimized.First, the evaluation on heterogeneity of zhao ao oil-field reservoir which is a steep slope fan delta sedimentary has been completed by studying on permeability contrast and interbed development.The results showed that interlayer heterogeneity and plane heterogeneity of this reservoir were stronger than its in-layer heterogeneity.And then,development effect evaluation system in ultra-high water cut period of edge water reservoir was established by using a series of evaluating indexes about waterflooding effect, for instance water consumption rate and so on. It is suggested that the effect of development of IV31 reservoir is getting worse, so stabilizing oil production and controlling water cut should be done in order to ensure development effect.Calibration system on recoverable reserves of IV31 layer series was established by using Tong's chart method,water drive curves,generalized water drive curve method,production decline curve method and so on. Conclusively, it is suggested that the calibration results of ultimate recovery are believable.At last,accoding to production decline curves,water drive curves and relative permeability curves, analysis and study on incremental rules of water cut of IV31 layer series was carried out,which is basically identical to incremental rules of water cut in practical production process.Because the relative permeability measured in the lab doesn't have representativeness as the homogeneity,wettability of the core and the time of the core saturated, however, the performance data could comprehensively reflect the reservoir and the process of the displacement of oil by water, the author calculated the permeability ratio curve by using the water driving characteristic curve during this research. And first taking the calculated result into the forcasting of the water ascending law, and the result is accordant to the actual situation.Then taking the result into the numerical simulation, and have matched the original geologic reserve, the average reservoir pressure,the daily oil production and the composite water cut,the effectiveness of the application is satisfied.The entire fit error is smaller than 7.5 percents,and the single well matching coincidence rate is 84 percents.At the same time,when studying the regular pattern of remainling oil distribution, the author according to the level of water out, divide three different areas. And the result indicate that because of the precipitation facie,the aeolotropism of reservoir,the distribution of original oil and the feature of well pattern,the remainling oil distribute straily. Subzone D1 to D3 flooding seriously,the remaining reserves is little;The sand body morphology of subzone D4 to D7 is small,and flooding softly,so the remaining reserves is high.At last,the author through analysing the well pattern account that now the well pattern is the economic rational well spacing density;But because the distribution factor of the reservoir sand is small,so the waterflood efficiency of the major reservoir is high,and opposite the non-major reservoir is low. The injection capacity and the well fluid is inconsistency,the flood effectiveness is bad.Associate with the affecting factor of the remaining oil and the pattern of the remaining oil,the author proposed some methods about the further exploitation of remainling oil,and at the same time designed three development plans.Passed ingoing analysis and optimize, finally we have choosed the third plan as the best plan.Through comprehensive evaluation we realizing that the combination of research and practice, put outcome of investigation into practice of production can make a good effect to freeze the production of oil and decrease the water-cut. This set a good model for the production of same type reservoir.