Evaluation of formation damage on productivity of hydraulically fractured horizontal wells in low permeability reservoirs.

摘要

Formation damage has been continuously affecting productivity of fractured wells. One of the most common techniques to enhance well productivity in low permeability reservoirs is hydraulic fracturing. Fracking operation is expensive and can cost up to 1 million dollar in some wells. A part of this expense is due to making fracturing fluid less damaging however the effect of damage on productivity of fractured wells is not clear.;The main purpose of this study is to establish a more realistic model to determine fractured well performance in horizontal wells. Subsequently, this analysis predicts the impact of fracture face matrix impairment on efficiency of fractured wells by relating productivity of non-damaged and damaged wells. It is preferred to determine the well productivity in terms of reservoir and fracture parameters in both damaged and undamaged fracture face matrix damage.;Assuming an elliptical geometry for the fracture shape a new model is developed based on reservoir linear flow. This research assumed that the flow to the fracture by the wellbore is linear and the flow to the rest of the fracture is considered pseudo-radial. It is believed that the reservoir influx is not uniformly distributed along the finite conductivity fracture, and this is the result of the fact that the sections near the fracture tip and head drain more oil or gas from larger areas compared to the sections of the same length near the wellbore. As a result, a function has been used to specify productivity index of the fractured well along the fracture. Additionally, the productivity and cumulative flow rates along the fracture are estimated and interpreted from the results of modeling.