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Due to very low permeability, wells in shale are normally drilled and completed as multiple fractured horizontal wells.  The rigorous analytical models of the multiple fractured horizontal wells were developed about 15 years ago for oil wells in a much higher permeability environment.  The flow regimes include early time linear flow and the compound linear flow had been discussed in detail.   It also has been observed that a unit slope line will be developed when more than 20 fractures are created.  This unit slope line is referred to the SRV unit slope line in literatures.

 

In this presentation, we will start our discussion from reviewing flow regimes of the rigorous multiple fractured horizontal well models.  Then, we move on to discuss the simplified SRV bounded and the trilinear models.  A comprehensive discussion of the characteristic behavior of a horizontal-well model that drains a reservoir through multiple fractures, highlighted significant features, and placed the approximate models that are commonly used to analyze responses in the context of rigorous predictions will be provided.  The scaling method to ensure that volumes drained by approximate models are correct will be presented. 

 

The second part of the presentation will be focus on the liquid-flow analog to evaluate gas wells producing in shales.

It has been suggested that the liquid-flow analog presented by Al-Hussainy et al. (1966) may not be adequate to evaluate the performance of gas wells in shale reservoirs.  A solution in terms of the similarity transformation is presented to examine the pressure distribution in a linear reservoir filled with a real gas.  The solution is intended to evaluate the early-time performance of gas wells producing through an infinite-conductivity fracture or through a horizontal well consisting of multiple, infinite-conductivity fractures.  The solution is particularly suited to evaluate the suggestion that the liquid-flow analog may not be appropriate to evaluate long linear-flow trends that are usually evident in shale wells in reexamined by considering 2D numerical solutions at a fractured well.  A method to adjust calculations to obtain estimates with reliable accuracy is presented. 

 

In the last part of the presentation, the practical issues on production analysis will be addressed and a workflow toward reliable analysis will be presented.  An example from Haynesville will be used to demonstrate the workflow. 

Please register prior to the event to facilitate improved planning and admission. Walk-ins will be accepted on a first come/ first serve basis as space allows.