Published

2014-05-01

Interpretation of pressure tests in hydraulically fractured wells in bi-zonal gas reservoirs

Interpretación de pruebas de presión en pozos hidráulicamente fracturados parcialmente penetrados en yacimientos de gas bi-zonales

Keywords:

Pressure derivative, fractured wells, mobility ratio, storativity ratio (en)
Derivada de presión, pozos fracturados, relación de movilidad, relación de almacenaje (es)

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Authors

  • Freddy Humberto Escobar Universidad Surcolombiana
  • Yu Long Zhao Southwest Petroleum University
  • Lie Hui Zhang Southwest Petroleum University

Due to the recent increase in the fracturing of low permeability formations, mathematical wellbore data interpretation has become important to generate mathematical models to study their pressure behavior and formulate interpretation methodologies for a more accurate characterization of tight hydrocarbon-bearing formations. This paper presents an analytical methodology of interpretation using the pseudopressure and pseudopressure derivative log-log plot for the characterization of hydraulically fractured (partially or fully penetrating) vertical wells completed in bi-zonal gas reservoirs. The methodology provided uses characteristic points and lines found on the pseudopressure and pseudopressure derivative plot so that new analytical expressions and correlations are developed to estimate half-fracture length, fracture penetration ratio, mobility and storativity ratios, radial permeability, size of the inner zone, well drainage area, vertical permeability and skin factor. The new expressions were successfully verified and tested with synthetic examples.

Dada la creciente demanda en el fracturamiento de formación de baja permeabilidad, la interpretación matemática de datos de pozos se ha tornado importante para la generación de modelos matemáticos que estudien el comportamiento de la presión y se formulen metodologías para una caracterización más exacta de formaciones apretadas que contienen hidrocarburos. Por ende, en este artículo se presenta una metodología para interpretar pruebas de presión en yacimientos gasíferos bi-zonales drenados por un pozo vertical hidráulicamente fracturado (penetración parcial o complete) que utiliza el gráfico log-log de pseudopresión y derivada de pseudopresión. La metodología dada usa líneas y puntos característicos hallados en dicho gráfico de modo que se desarrollaron nuevas expresiones y correlaciones para longitud media de fractura, relación de penetración de la fractura, relaciones de movilidad y almacenaje, permeabilidad radial, tamaño de la zona interior, área de drenaje, permeabilidad vertical y factores de daño. Las expresiones nuevas se verificaron exitosamente mediante ejemplos sintéticos.

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References

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Copyright (c) 2014 Freddy Humberto Escobar, Yu Long Zhao, Lie Hui Zhang

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