Considerations for Production Forecasting and Field Development in an Under Developed Field in a Geologically Complex Reservoir System: Chicontepec Basin Example

Abstract

Abstract The exploitation of the under developed fields in the Chicontepec basin is difficult mainly due to uncertainty in production forecasts as a result of complex geology, variations in fluid properties, and lack of data quality. Under these circumstances sole use of decline curve analysis is not sufficient, and it includes major uncertainty with respect to well performance. Along these lines the focus of this work is to present an efficient methodology using model-based analysis within a probabilistic framework as the foundation for field production forecasting to find better areas for development in the Chicontepec basin. The methodology includes constructing a well/reservoir model based on future development considerations in this geologically complex environment. An experimental design procedure is used to account for the uncertainty in both reservoir and well properties. Using analogous field analysis and available information (PVT, production data, geological information), distributions for key parameters, such as permeability, thickness, area; were determined and the statistical distribution of Estimated Ultimate Recovery (EUR) values were found using the numerical model-based simulation. The field development methodology is based on well spacing analysis, targeted production locations, and various well orientations for the geologically complex reservoir system. The numerical model-based derived profiles are projected throughout the under developed field with the field development methodology to complete the full field production forecast. A response surface equation was observed to relate the reservoir properties, fluid properties, and well completion properties of the numerical based-model to the EUR values found from the proposed methodology. Running a Monte Carlo simulation with the response surface equation and probabilistic distribution of key parameters P90, P50 and P10 EUR values and associated type well profiles for the full field development scenarios were determined. Experimental decline curve analysis of a developed field in the Chicontepec Basin predicts oil recovery factors from 6% to 13%. Following the methodology presented in this work, oil recovery factors of the same field were found to be 6% to 15%. Based on comparisons of the presented methodology and empirical decline curve analysis, the experimental design framework for analysis offers a viable option to decline curve analysis for full field production forecasting when little or unreliable production data is available. This work provides a thorough description of a workflow for a probabilistic approach to full field production forecasting in a geologically complex reservoir system such as the Chicontepec basin.