Factors Controlling the Flowback Behavior of Hydrocarbon Bearing Formation

by
Rana Sinha Roy, MSE

University of Texas at Austin, 2001
Supervisor: Mukul M. Sharma

This thesis presents a study of different factors that control the clean-up of damage due to drill-in fluids on different reservoir rocks. The two important factors studied are, solids invasion and filtrate invasion (relative permeability effects). The aim of this study is to identify the conditions under which solids invasion and filtrate invasion effects can play important roles. The flowback properties that were recorded to quantify the extent of damage are the Flow Initiation Pressure (FIP) and the Return Permeability.

Experiments are conducted with brine saturated cores and cores containing a residual brine saturation. FIP measured by flowing back with brine and oil are compared. The results show that, for low permeability rocks and small mobility ratios, relative permeability effects appear to play a dominant role. For higher permeability rocks (>100 md) and large mobility ratios, solids invasion becomes increasingly significant. A key difference between these two components of FIP is that while relative permeability effects will dissipate with time, internal filter cakes may not.

A simple model is presented to calculate the pressure profile in displacement experiments in cores.

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