• Well Loss in Fractured Rock Formation with Radial Flow during Pumping Test
  • 양수시험시 방사상흐름을 보이는 균열암반 대수층에서의 우물손실
  • 이철우;이대하;정지곤;김구영;김용제;
  • 한국지질자원연구원 환경지질연구부;한국지질자원연구원 환경지질연구부;충남대학교 지질환경공학부;한국지질자원연구원 환경지질연구부;한국지질자원연구원 환경지질연구부;
Abstract
Pumping tests were carried out from seven wells in fractured rocks. The time-drawdown data were obtained from pumping wells and corrected for the elapsed time of step drawdown test using Cooper-Jacob's method. A statistical method. the least square of error, was used to yield the coefficient of aquifer losses, the coefficient of well losses, and the power which indicates the severity of the turbulence. The values of the power range from 1.65 to 6.48. The well losses result mainly from turbulent flow caused by radial flow nearby pumping wells. The turbulent flow depends on Reynolds number. Since the hydraulic characteristics of fractured rocks control the fluid velocity, the value of the power is an important factor to understand the aquifer system of fractured rocks.

균열암반내에 시추된 7개의 양수정에서 양수시험을 실시하였다, 여기에서 각 양수율에 따른 수위강하값을 구하였으며, 비평형상태하에서의 단계양수시험은 Cooper-Jacob의 방법에 의해 양수시간을 보정하였다 양수정에서의 대수층 손실상수, 우물손실상수 및 우물손실지수(n)의 산출은 최소제곱법(method of the least square)을 이용한 회귀분석 방법을 이용하였으며, n값의 범위는 1.65∼6.48로 산출되었다. 균열암반내에 시추된 양수정의 우물손실은 케이싱이나, 시추시 발생되는 공벽의 공극감소 등의 영향보다는 방사상흐름에 따른 양수정부근에서의 난류에 의한 영향이 대부분일 것으로 해석된다. 또한 이 난류는 레이놀즈의 수(Reynolds number)에 좌우되는데, 여기에서 암반대수층내의 균열 특성이 유체의 속도를 지배하므로 정확한 n값의 산출은 암반대수층을 이해하는데 중요한 인자가 될 것이다.

Keywords: Well loss;Fractured rocks;Step drawdown test;Method of the least square;Radial flow;

Keywords: 우물손실;균열암반, 단계양수시험;최소제곱법;방사상흐름;

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This Article

  • 2002; 7(4): 17-23

    Published on Dec 1, 2002