稠油油藏水侵制约要素的研究

Research of Restricting Factors of Water Invasion in Heavy Oil Reservoir

锦91块已进入吞吐开发后期且水淹严重,边底水稠油油藏转蒸汽驱缺乏理论依据。实验采用三层非均质人造岩心,气测渗透~分别为500×10-3、1000×10-3、1500×10-3μm2,中心5口生产井,外围4口饱和油的辅助生产井,右边4个进水口模拟充足的边水水体,靠近边水有宽度为2 cm的高渗(渗透~16000×10-3μm2)过渡带。分析了压差、温度、边水距离等因素对边底水水侵敏感性的影响。结果表明:在45℃、压差(ΔP)分别为0.04、0.06、0.08 MPa时,实验前期和后期,瞬时水侵量Q与ΔP的关系分别为Q=0.0021×e72.8ΔP×t(t=0~75 h)和Q=0.007×e51.708ΔP×(t-75)+0.157e72.64ΔP(t=75~125 h)。压差较小时,Q与时间近似为线性关系;随着压差的增加,瞬时水侵量变化曲线出现拐点;水侵后期瞬时产水量趋于稳定。温度由45℃增至75℃,生产井见水时间延后,温度对距离边水较远的生产井见水时间影响最为明显。距离边水越近,水淹越严重。在诸多水侵敏感因素当中,压差对水侵规律的影响最为明显。此结果为重水淹区转蒸汽驱开发提供了依据。

Jin-91 block entered the later period of steam huff-puff and was flooded seriously,which lacked the theory of steam flooding in heavy oil reservoir with edge and bottom water. Three layers of inhomogeneous artificial core with 500×10-3、1000×10-3、1500 × 10-3μm2permeability were used in experiment. There were 5 producing wells,four assist production wells which were designed for saturating core with oil,four water inlets which were used for modeling sufficient edge water on the right. High permeability(16000 × 10-3μm2)transition with 2 cm width was close to the edge water. The effect of pressure,temperature and distance of water and bottom water on the encroachment sensitivity of edge-bottom water was analyzed. The results showed that when the differential pressure(ΔP)was 0.04,0.06,0.08 MPa and the temperature was 45℃,the relationship between instant water influx Q and ΔP was Q=0.0021×e72.8ΔP×t(t=0~ 75 h)and Q=0.007×e51.708ΔP×(t-75)+0.157e72.64ΔP(t=75~ 125 h)in early and later stage of the experiment,respectively. When ΔP was small,the relationship between Q and time was approximately linear.With increasing ΔP,the curve of Q appeared inflection point. And the instant water-output tended to be stable at later stage of water invasion. When the temperature increased from 45℃ to 75℃,the water breakthrough time delayed. The effect of temperature on water breakthrough time of producing wells far from edge water was the most obvious. The nearer to edge water,the more serious water logging was. The effect of ΔP to the law of water invasion was the most obvious among water invasion sensitive factors. The result provided evidence for the development of heavy water flooded zone turning to steam drive.