油井合理井底流压综合判定方法

合理井底流压是充分发挥油井产能、提高油田开发效益的保证,但现在缺乏一种合理的综合性判定方法。在分析生产气油比、产层出砂、应力敏感和层间干扰等4个因素对合理井底流压影响规律的基础上,根据模糊变换原理建立了油井合理井底流压综合判定数学模型。利用该数学模型,可定量计算考虑不同因素、不同因素权值影响下的合理井底流压。实例计算表明,所建立的油井合理井底流压综合判定数学模型具有较高的计算精度,可为油井设计合理流压、配产提供理论指导;利用实例的数据分析了合理井底流压对渗透率变异系数、生产气油比、泊松比等参数的敏感性,结果表明:渗透率变异系数越大,为维持储层的渗流能力,需要保持越高的井底流压;生产气油比越高,为确保抽油泵泵效,需要保持越高的井底流压;对于泊松比较大的疏松砂岩储层,为防止地层出砂,需要保持较高的井底流压。 

Integrated Evaluation Approach of Reasonable Bottom-Hole Flowing Pressure of Oil Wells

Reasonable bottom-hole flowing pressure is the guarantee for the full play of oil wells’ productivity and improvement of oilfields’ development efficiency,but an accurate,reasonable and integrated evaluation approach is not available yet on well site.Based on the analysis on the influence of produced gas oil ratio,sand production,stress sensitivity and interlayer interference on reasonable bottom-hole flowing pressure,a mathematical model of integrated evaluation approach of reasonable bottom-hole flowing pressure was built using the principle of fuzzy transform.The mathematical model can do caculation considering the impact of different factors and different factor weights.The calculation and analysis of actual example showed that the evaluation approach of flowing pressure proposed in this paper had high calculation accuracy.This could provide theoretical guideline in reasonable flowing pressure design and proration production.In addition,the sensitivity of reasonable bottom flowing pressure to permeability variation coefficient,oil gas ratio,Poisson’s ratio and other parameters were analyzed with real field data.The results showed that: for reservoirs with high permeability variation coefficient,high reasonable bottom-hole flowing pressure should be maintained in order to keep the reservoir’s seepage ability;For the wells with high produced oil and gas ratio,high reasonable bottom-hole flowing pressure should be maintained to ensure the pumping efficiency;High reasonable bottom-hole flowing pressure should be kept for unconsolidated sandstone with high Poisson’s ratio in order to prevent sand production.