我国河流相与三角洲相储层水驱油效率研究

Study of Oil Displacement Efficiency for Fluvial and Delta Facies Reservoirs of Oilfield in China

罗　洪,俞启泰

Luo Hong,Yu Qitai

北京石油勘探开发科学研究院

Scientific Research Institute of Petroleum Exploration and Development, CNPC ,Beijing 100083 , P. R. China

我国河流相与三角洲相储层的地质储量约占总开发储量的70 %以上。用油田岩心试验等实际数据统计研究了河流相与三角洲相的平均渗透率K 、平均地层原油粘度μ_o 、平均地层水粘度μ_w 、平均油层温度T 和平均油水粘度比μ_R ,结合典型油水相对渗透率曲线,计算了河流相与三角洲相储层最大驱油效率ED1. 0 (含水率100 %的驱油效率) 、含水率98 %的驱油效率ED0. 98 和流度比M ,并得出了水驱油田最大驱油效率E_{D1. 0} 、含水率98 %的驱油效率E_{D0. 98} 和流度比M 的回归公式。分析认为,提高储层的注入波及程度是今后油田挖潜的重点。

The reserves influvial and delta facies reservoirs of oilfield in China are nearly over 70 % of total development reserves. The average permeability K ,average oil viscosityμo ,average formation water viscosityμw ,average oil reservoir temperature T and average oil-water viscosity ratioμR for fluvial and delta facies reservoirs have been studied by field core data ,with typical oil-water relative permeability curve ,mobility ratio and oil displacement efficiency which water cut is 100 % and 98 % have been computed and regression formulas are concluded. There are four major points have been found :At first ,the value of K ,μo ,μw ,μR for fluvial facies reservoirs are 1 584 ×10 – 3 μm2 ,32. 2 mPa•s ,0. 463 4 mPa•s and 69. 51 ,higher than those of delta facies reservoirs : 1 038 ×10 - 3μm2 , 25.1 mPa•s ,0. 446 5 mPa•s and 53. 14. The second ,computed by the average value of the reservoirs , the value of ED1. 0 and ED0. 98 for fluvial facies reservoirs are 0. 666 4 and 0. 504 5 , lower than the values of delta facies reservoirs : 0. 689 2 and 0. 551 2 ;mobility ratios of fluvial facies reservoirs is 2. 544 7 ,higher than delta facies reservoirs :2. 394 9 , both are bad mobility ratios , but in the conditions , such as the reservoirs are low permeability and low viscosity ,perhaps the mobility ratio is less than 1 and become good mobility ratio. The third ,for fluvial and delta facies reservoirs , ED1. 0 only depends on K and increased with K , ED0. 98 is affected by K and μR , increased with K , decreased with μR and the affection of μR is more than K. The last ,the average recovery ratio for fluvial and delta facies reservoirs in China is 0.302 and 0.365 respectively ,far lower than ED0. 98 and ED1. 0 , it has been seen , for fluvial and delta facies reservoirs , until development over , the sweep condition is very poor , so it is very important for later field development to improve the sweep efficiency.