The idea of continuous assessment of individual well performance is imperative globally to E&P organizations when it comes to production optimization regimes and increasing profitability from each barrel of oil present. One of the most effective ways to assess this performance is through the use of Inflow-Performance Relationship (IPR) & Outflow-Performance Relationship (OPR) curves. Consequently, the use of the pertinent IPR which is representative of the performance is essential.

Vogel's IPR has been employed in the industry more like a standard when it comes to conventional reservoirs well performance. Moreover, Vogel's IPR model can successfully model IPR for vertical wells in a homogeneous reservoir producing from solution gas drive mechanism. However, current IPR models for horizontal wells are only valid for single porosity reservoirs, and their applicability to dual porosity/dual permeability reservoirs is questionable. The complexity in such reservoirs arise due to the combined flow between the distinct systems of the matrix and fracture, and as a result, it is imperative to develop a new IPR model that incorporates the impact of the fracture parameters.

This work focuses to inspect effects of the complex flow behavior on the inflow curves, concentrating on horizontal wells in NFR's. Foundation of this work is based on the development of a base case black oil computational model incorporating typical reservoir and PVT properties. Finite number of data points linking oil rate to flowing bottom-hole pressures were used to generate the dimensionless IPR curves. Wide-ranging PVT and particular reservoir properties concerning two systems of porosity and permeability were used which included; Inter-porosity flow co-efficient, storativity ratio, normalized horizontal well length, reservoir thickness and saturation pressure. As expected, it was concluded that the NFR parameters of storativity and inter-porosity flow coefficient, along with the normalized horizontal well length had substantial control on dimensionless IPR curve. To further augment the results, effort is expended to congregate outcomes into one unpretentious model using a combination of support vector machine and non-linear regression techniques along with the particle swarm optimizer to formulate a new empirical IPR equation.

The newly suggested pragmatic IPR model produces results within acceptable absolute error range of 2%, when compared with the actual data. Accordingly, this proves that the developed correlation is very accurate and can prove to be a vital tool for production/reservoir engineers concerned with the production optimization/enhancement of horizontal wells in naturally fractured dual porosity-dual permeability reservoirs.

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