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Optimization of gas-lifted oil wells

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Decline Curve Analysis software to forecast oil and gas wells

DynamicForecaster has integrated Decline Curve Analysis software to forecast oil and gas wells.

Wells decline curve analysis comparison

Wells decline curve analysis comparison

Historical diagnostic analysis is performed by automated curve-fitting, then the relevant parameters are used for forecasting.

Comparison of DCA methods:

  • Exponential decline,
  • Hyperbolic decline,
  • Power Law Exponential decline,
  • Transient Hyperbolic decline.

References:

References for Decline Curve Analysis (opens in a new page)

Production Analysis

Further charts show flow-rates ‘normalized’ by the approximate pressure drop within the reservoir and plotted against log(mass balance time) or the square root of time.

Wells decline curve analysis time-rate-pressure

Wells decline curve analysis time-rate-pressure

 

Coal Seam Gas (CSG) Wells – calculate FBHP

Very few Coal Seam Gas Wells have permanent downhole pressure gauges, but well productivity depends crucially on the downhole pressure.  To assess and predict field-level performance, it is essential to estimate the downhole pressure at least daily for all wells.

DynamicForecaster rapidly calculates the well performance from surface measurements:

  • Flowing Bottom Hole Pressure (FBHP), allowing for bubbly water in the annulus
  • Progressing Cavity Pump (PCP) performance, to monitor the actual performance versus expectations
  • Turner critical gas velocity, for lifting water up the annulus.

High calculation speed

The typical calculation speed exceeds 500/second for the round trip (retrieve data, calculate, store results).  This enables fast review of historical well performance.  For example, 3 years of daily calculations for 10 wells takes just 15 seconds.

Shale Gas Wells – calculate FBHP

Calculations from surface measurements include: Turner critical gas velocity for lifting water and Flowing Bottom Hole Pressure (FBHP).

 

Fluid flow (pressure loss) calculations

In DynamicForecaster, pressure loss calculations for fluid flow in wells and pipelines have many selectable options:

  • gas or liquid
  • friction factor method
  • real gas compressibility (Z-factor) method
  • gas viscosity method
  • calculation direction (upstream or downstream)

Dimensions of well tubulars and pipelines are retrieved from the relevant database.