Reservoir Opportunity Index - Advance in Well and Subsurface Design for Cost Effective Field Development

Abstract

Abstract Phase development is key to any successful field development in complex and compartmentalized reservoirs. The balance of cost, value and risk drives the oil companies to learn from well and reservoir data as they develop the field. Naturally, well productivity will enhance in each phases, by a better well and completion design while the remaining mobile oil, hydrocarbon saturation and reservoir pressure are diminishing. Subsurface target selection and ultimately well design needs to be optimized rigorously in order to meet the expected value of each well in every drilling campaign. This paper gives a new insight in Reservoir Opportunity Index (ROI) or Simulation Opportunity Index (SOI) which combines the key elements of each target (Flow Capacity, Remaining mobile oil and pressure) into a normalized parameter. There are several papers1,2,3 which introduce the application of this method in several case studies. All of those works is guided by existing simulation model which is history matched until present time. The model is then used to generate the SOI map with the MAX (SOI) function will be treated as the optimize location for future well location. We had tested this method in several case studies and have found that more detail analysis in SOI indexes are needed before accepting the results of the MAX (SOI) function. Having several infill drilling campaign in the past gives us an opportunity to evaluate the SOI based on the previous data and production performance. Correction of the mathematical function may be needed to better match the historical data which is not limited to production only but the Productivity Index (PI), pressure and remaining oil map. The method have been applied in several cases including a tight gas reservoir and two vast multiple stacked oil reservoirs with reliable full field model. It will be shown in this paper that this method gives a more reliable targets in subsurface and well design and hence introduced as an integrated part of well optimization workflow. Like other methods, it should be used with care as there are limitations in each case. This paper highlights those limitations that have been observed in our work and advised how to overcome the limitations.