地层平均压力计算方法研究

发布时间：2018-03-13 01:18

本文选题：地层平均压力　切入点：试井分析方法　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：试井是评价油气藏开发动态的重要技术方法和基础工作之一。压恢试井是目前常用的一种方法,通过MBH曲线等计算出地层平均压力等。地层平均压力可以用来预测油藏未来动态、计算原始地质储量以及描述油气藏特性,在一次开采、二次开采和压力保持过程中,评价油藏动态和井工作状况具有十分重要的作用。本文给出了正六边形、矩形地层、直角三角形、正三角形、菱形一口井的镜像反演方法,反演后再应用叠加原理就很容易求得地层的压力分布以及产能公式,同时可以用此方法得出不同规则几何形状的MBH函数。通过对Russell的圆形封闭油藏一口井的压力恢复解析式进一步推导严格证明了Muskat等人经验结论的正确性,并用实例验证其具有较高的精度。根据地层平均压力的定义,对不稳定渗流控制方程组进行积分,或者积分对应的压力分布函数(控制方程组的解式),求取圆形封闭油藏压力降落过程中的地层平均压力的变化规律。两者的结果一致。运用叠加定理,求取圆形封闭油藏压力恢复过程中的地层平均压力变化规律。随着压恢时间的增大,地层平均压力逐渐增大,但变化减慢,恢复到一定程度保持不变;生产时间越长,相应的地层平均压力越小。根据地层平均压力的定义,对不稳定渗流控制方程组进行积分,并运用格林定理求取常规气藏平均压力变化规律。早期不稳定流动阶段,平均压力为一重合的曲线,随时间的增大,平均压力逐渐减小,随着边界范围的增大,边界流发生时间越晚。当压力波传到边界之后,由于地层是封闭的,此时整个地层压力都下降,井的产量完全来源于压力下降引起的流体和岩石体积膨胀而释放的弹性能,经过一段时间后,地层各处的压力降落速度相同,都等于泄流区内平均压力降落速度,达到拟稳态渗流。根据地层平均压力的定义,对不稳定渗流控制方程组进行积分,并运用莱布尼茨公式求取低渗透储层平均压力变化规律。随着时间的增大,地层平均压力逐渐减小,且变化减慢;启动压力梯度越大,到达物理边界越晚;到达边界后,地层平均压力与时间呈线性关系。启动压力梯度越大,地层平均压力越小。
[Abstract]:Well testing is one of the important technical methods and basic work for evaluating the development performance of oil and gas reservoirs. The average formation pressure can be used to predict the future performance of the reservoir, calculate the original geological reserves and describe the characteristics of oil and gas reservoir. It is very important to evaluate reservoir performance and well working condition. In this paper, a mirror image inversion method for hexagon, rectangular formation, right triangle, regular triangle and diamond well is given. After inversion, the pressure distribution and productivity formula of the formation can be easily obtained by applying the superposition principle. At the same time, the MBH function with different regular geometry can be obtained by this method. The accuracy of the empirical conclusion of Muskat et al is proved strictly by deducing the pressure recovery analytic formula of a well in a circular closed reservoir of Russell. According to the definition of average formation pressure, the governing equations of unstable seepage flow are integrated. Or the pressure distribution function corresponding to the integral (the solution of the governing equations, the law of the variation of the formation average pressure during the pressure drop of the circular closed reservoir) is obtained. The results of the two methods are consistent, and the superposition theorem is used. With the increase of pressure recovery time, the formation average pressure increases gradually, but the change slows down, and the recovery to a certain extent remains unchanged; the longer the production time, the longer the formation average pressure is. According to the definition of average formation pressure, the governing equations of unstable seepage flow are integrated, and the law of average pressure variation in conventional gas reservoirs is obtained by using Green's theorem. The mean pressure is a coincidence curve. With the increase of time, the average pressure decreases gradually. With the increase of the boundary range, the boundary flow occurs later. When the pressure wave reaches the boundary, the formation is closed. At this point, the whole formation pressure is reduced, and the production of the well is completely derived from the elastic energy released by the volume expansion of the fluid and rock caused by the pressure drop. After a period of time, the pressure drop rate throughout the formation is the same. According to the definition of average formation pressure, the governing equations of unstable seepage flow are integrated. With the increase of time, the average formation pressure gradually decreases and the variation slows down. The bigger the starting pressure gradient is, the later it reaches the physical boundary, and the later the formation pressure reaches the physical boundary after reaching the boundary. The average formation pressure is linearly related to time, and the larger the starting pressure gradient is, the smaller the formation average pressure is.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE271

【参考文献】