Optimization of artificial lift modes in Halfaya Oil field by means of multi-level fuzzy evaluation method

Halfaya Oil field is located in the southeast of Iraq. There are more oil-bearing series of strata and they are faced with many production problems (e.g. high producing gas/oil ratio, sulfur bearing, sand production and asphalt precipitation), which bring great challenges to the selection of artificial lift modes. To select the artificial lift mode suitable for the characteristics of each series of strata, multiple factors were taken into consideration comprehensively, including oil reservoir characteristic, fluid physical property, borehole condition, lifting equipment characteristic and capital cost, and a comprehensive evaluation model for evaluating the factors in fl uencing the artificial lift modes of the target layers in Halfaya Oil field was established by means of multi-level fuzzy evaluation method. Then, based on the production status of this oil field, the decision making factor of each lift mode was calculated and the optimal lift mode was selected specifically for each series of strata. The pilot test in the oil field shows that the optimized model is practically applied well with good technical suitability and rational economic cost control. It provides the technical guide, experience and reference for the full-scale artificial lift production of the oil field in the later stage.