Fracture diagnostic using distributed temperature measurements during a pause in flow-back period
Fracture diagnostic using distributed temperature measurements during a pause in flow-back period
复制标题
使用回流期间暂停期间的分布式温度测量进行断裂诊断
DOI：
10.1016/j.petrol.2019.106632
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发表时间：
2020
影响因子：
--
通讯作者：
M. Gysen
中科院分区：
文献类型：
--
作者：
Y. Mao;M. Zeidouni;C. Godefroy;M. Gysen
增产流体回流期间裂缝区域与非裂缝区域之间的显着温差对于裂缝诊断非常有用。井下温度监测系统的最新发展为检测这些温度变化以执行生产测井分析提供了新的可能性。在这项工作中，我们得出了一种新颖的分析解决方案来模拟与回流和生产期间关井相关的温度信号。温度行为可以推断每个断裂的效率。为了从现有井筒流体能量平衡方程获得解析解，我们使用特征法并输入相关的热边界条件。从该解析解获得的温度建模结果与多种情况下的有限元模型的结果进行了验证。与关井后非裂缝区域的暖回效应相比，在裂缝区域观察到的加热效应不太明显，因为远离射孔的较热流体进入裂缝（后流）。对续流速度及其变化、各裂缝的流动、地热和流入温度、周围温度场和套管半径进行详细的参数分析，研究它们对井筒流体温度模拟结果的影响。反演程序根据裂缝和非裂缝区域的解析解，考虑温度的指数分布，刻画各裂缝的特征。可以根据测量的温度数据估计每个裂缝的流入流体温度、周围温度场和后流速度，这对分析合成温度信号具有良好的精度。每个集群的估计都是独立的，可以将其组合起来分析整个生产部分。这项工作的成果有助于生产测井、回暖和井筒存储分析，以实现成功的裂缝诊断。
The significant temperature difference between the fractured and non-fractured regions during the stimulation fluid flow-back period can be very useful for fracture diagnosis. The recent developments in downhole temperature monitoring systems open new possibilities to detect these temperature variations to perform production logging analyses. In this work, we derive a novel analytical solution to model the temperature signal associated with the shut-in during flow-back and production periods. The temperature behavior can infer the efficiency of each fracture. To obtain the analytical solution from an existing wellbore fluid energy balance equation, we use the Method of Characteristics with the input of a relevant thermal boundary condition. The temperature modeling results acquired from this analytical solution are validated against those from a finite element model for multiple cases.Compared to the warm-back effect in the non-fractured region after shut-in, a less significant heating effect is observed in the fractured region because of the warmer fluid away from the perforation moving into the fracture (after-flow). Detailed parametric analyses are conducted on after-flow velocity and its variation, flowing, geothermal, and inflow temperature of each fracture, surrounding temperature field, and casing radius to investigate their impacts on the wellbore fluid temperature modeling results.The inversion procedures characterize each fracture considering the exponential distribution of temperature based on the analytical solutions in fractured and non-fractured regions. Inflow fluid temperature, surrounding temperature field, and after-flow velocity of each fracture can be estimated from the measured temperature data, which present decent accuracies analyzing synthetic temperature signal. The estimations are independent on each cluster, which can be combined to analyze the entire production section. The outputs of this work can contribute to production logging, warm-back, and wellbore storage analyses to achieve successful fracture diagnostic.