FLAC3D應用於儲集層岩盤應力之分析

規劃舊氣田或開發地下水層為地下儲氣窖早已行之有年，以國內位於苗栗之鐵砧山油氣田為例，此氣田是臺灣最大的油氣田，自1965年開始生產以來，歷經30餘年的開採已漸枯竭。因此目前利用此氣田作為地下儲氣窖，就近調節北部天然氣尖峰、離峰時段之用氣需要。本研究之目的即在於了解儲氣層之應力狀態，以確保地下儲氣窖之有效儲氣能力及產能。研究架構主要分為三個部分，分別為：(一)應用井孔崩落(Borehole breakouts)分析，找出儲氣層中水平最大主應力( )之方向；(二)應用有限差分軟體FLAC3D，評估地層應力大小；(三)應用倒傳遞類神經網路分析，找出影響地層應力方向及大小之重要因子。蒐集充足且合適之鑽井電測資料(Caliper logs)為本研究最重要的工作之一，目前蒐集有六口井的電測資料，經研究結果發現，A3與B3井的平均水平最大主應力方向分別為N80.1W與N28.5W；地層中的側向最大水平壓力係數的範圍約介於1至2之間，而側向最小水平壓力系數的範圍約介於0.4至0.8之間，至於影響該地層應力大小最重要的因子，以目前電測資料來說是井徑(1-3)的尺寸。

關鍵字

井徑電測資料； FLAC3D ；井孔崩落；應力分佈

並列摘要

The use of depleted natural gas reservoir and aquifer as the Natural Gas underground storage have become more and more popular for the past decades.For example, the largest oil gas field located in Tie Zhen Shan of Miao Li County in Taiwan. Which has been more than thirty years since it began to produce oil gas in 1965. Due to it’s depletion, the gas field is now utilized as an underground gas storage reservoir to regulate the need of gas supply during peak and off-peak demand in northern Taiwan. The purpose of this research is to analyze the stress distribution of the underground NG storage reservoir formations. For securing the effective capacity and production of gas. The structure of this research is divided into three parts including: (1) breakout data analysis obtained from oriented four-arms caliper logs in 6 wells to provide the orientation of maximum and minimum horizontal stress ( ); (2) estimate the stress distribution of the gas reservoir by finite-difference model FLAC3D ; (3) apply Artificial Neural Networks (ANN) to reveal the factors that influence the stress distribution. The borehole breakouts and tensile fractures analysis results indicate that the average direction of the maximum horizontal stress, , is oriented approximately in N80.1˚W for TCS-A3 and N28.5W for TCS-B3 well. At 2700 m depth of the underground NG reservoir the maximum horizontal stress is approximately between 1 and 2 of the vertical stress . The borehole diameter variation of the caliper(1-3) is the most important factor affecting the magnitudes and directions of the stress of the reservoir.

並列關鍵字

Caliper logs ； FLAC3D ； Borehole breakout ； Stress distribution

參考文獻

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FLAC3D應用於儲集層岩盤應力之分析

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