裂缝性潜山稠油油藏产能影响因素分析

Analysis of Influencing Factors about Productivity in Buried Hill Fractured Heavy Oil Reservoir

针对裂缝性潜山稠油油藏存在应力敏感以及稠油流动存在启动压力梯度门限,建立了考虑应力敏感和稠油可流动性的产能计算公式并分析了产能影响因素。以渤海东部海域某区块为例油井产能随黏度的增加成指数减小;油井产量随裂缝开度和裂缝密度的增加而增大。裂缝开度较大时,产量随开度成指数增长;裂缝密度对产能的影响与开度有关。开度较小时,密度影响也较小,随着开度的增大,密度影响大幅度增加。基质孔隙内原油的可流动性可利用启动压力梯度判定,启动压力梯度越大日产量越小;若裂缝性油藏基质原油不可流动,则油井产量下降很快,产量很小,因此充分考虑基质原油的可流动性是非常有必要的。

Considering existence of the stress sensitivity and threshold pressure gradient when oil flows in buried hill fractured heavy oil reservoir, a formula for productivity calculation in view of the stress sensitivity and heavy oil flow capacity is established. The analysis of factors affecting productivity indicates that well productivity decreases with the viscosity rising. With the increasing of fracture aperture and density, well productivity increases. When fracture aperture is relatively large, the production grows exponentially with fracture aperture growth. The effect of fracture density on the productivity has something to do with aperture. When aperture is small, the effect of fracture density is small while the effect level of fracture density grows considerably with the increase of the aperture. Oil flow capacity of the matrix porosity can be determined by threshold pressure gradient. The larger threshold pressure gradient, the smaller production rate. If oil cannot flow in fractured reservoir matrix, the oil production declines rapidly and the production is very small, so it is necessary to pay attention to the flow capacity of oil in matrix.