Abstract Deliverability of gas and liquid hydrocarbons in retrograde condensate systems is highly affected by factors related to both reservoir characteristics and operative variables. It is well documented that pressure depletion coupled with tight petrophysical environments can lead to severe PI decrease due to liquid accumulation initially in the near wellbore area and then in the whole reservoir. Conventional approaches for condensate blockage removal have included the injection of low interfacial tension systems and alcohol blends to promote capillary forces minimization up to levels at which liquid bank gets remobilized. This type of solutions though, can be durability limited as liquid will reform once chemicals leave treated area. This condition become even more critical when static reservoir pressure gets below dew point as liquids from non treated zone will rapidly imbibe into the treated zone decreasing durability even further. The present work documents a field trial of a fluoro polymer technology aimed on Kro and Krg enhancement by rock wettability modification. This technique, as opposed to conventional chemistries working at the fluid-fluid interaction level, is aimed on altering rock's original wettability. The objective is to promote a neutral wettability condition to minimize capillary effects driven by the contact angle according to LaPlace equation (fig 1). Through a "facts and gaps analysis", a set of root causes are presented to explain the high PI improvement (–50%) but limited durability observed at field scale. Uncertainties on original rock wettability condition, water saturation profile in the near wellbore, deployment technique effectiveness and chemical properties of size and adsorption are all included in the root cause analysis. Data from pre job coreflood tests, pumping variables behavior and backflowed samples chemical analysis are also incorporated to the exercise. A final set of recommendations derived from the f&g analysis are to be included in further trials of the wettability modification technology where heterogeneous sandstone, compositional condensate environments are present.
Tópico:
Hydraulic Fracturing and Reservoir Analysis
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15
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Información de la Fuente:
FuenteSPE Latin America and Caribbean Petroleum Engineering Conference