Solution and type curves for the seepage model of the water-bearing coalbed with leakage recharge

To analyze the effects of the leakage recharge of the aquifer on the initial dewatering of coalbed methane wells, the mathematical seepage model of water in the coalbed considering the aquifer leakage was established by using the leakage coefficient according to the unsteady seepage theory. The mode...

Full description

Autores:
Chen, Wangang
Yang, Yu
Sun, Hansen
Zhang, Chengwei
Wen, Qin
Li, Yanyan
Tipo de recurso:
Article of journal
Fecha de publicación:
2017
Institución:
Universidad Nacional de Colombia
Repositorio:
Universidad Nacional de Colombia
Idioma:
spa
OAI Identifier:
oai:repositorio.unal.edu.co:unal/63590
Acceso en línea:
https://repositorio.unal.edu.co/handle/unal/63590
http://bdigital.unal.edu.co/64036/
Palabra clave:
55 Ciencias de la tierra / Earth sciences and geology
Coalbed methane (CBM)
Formation water
Leakage
Well test analysis
Gas metano de carbón (CBM)
formación de agua
pérdida de fluido
análisis de pozo
Rights
openAccess
License
Atribución-NoComercial 4.0 Internacional
Description
Summary:To analyze the effects of the leakage recharge of the aquifer on the initial dewatering of coalbed methane wells, the mathematical seepage model of water in the coalbed considering the aquifer leakage was established by using the leakage coefficient according to the unsteady seepage theory. The model was solved after Laplace transform and the Stehfest numerical reverse inversion was used to obtain the solution in right space. Then, the log-log type curves of pressure and pressure derivative were created with new combinations of parameters. Based on the natural seepage mechanism, the influence of aquifer leakage on curve shape was judged. It is found that the radial flow ends earlier as the leakage coefficient increases. Moreover, it was proposed to obtain reservoir permeability, skin factor, and leakage coefficient by using type curve matching. The type curves are useful for quantitatively evaluating the level of leakage, thereby guiding the adjustment of the following production system for CBM wells.