Evaluation of Giant New and Mature Oil Fields Developments - History and Prediction Study for Applying Horizontal Wells Using Simulation and Field Practices

Abstract

Developing giant new and mature oil fields by horizontal drilling is one of the most valuable technologies employed nowadays since it can maximize mature field's benefits. Horizontal wells are offering multiple advantages including, higher production rates, better drainage, lower drawdown and delay water production. In addition, especially in offshore fields, horizontal wells compromise the ability to drill more multi-lateral wells from a single platform enhancing ultimate recovery because of reaching the bypassed oil buckets away from the offshore jackets reducing the number of vertical wells and minimizing offshore infrastructures reducing costs and time. These technologies have been, and will become an attractive topic for more studies and investigations. Development of mature fields, could be included into three major categories (a) well engineering (b) surface facilities and (c) reservoir engineering. This paper focuses on the reservoir engineering aspects and mainly on applying horizontal wells in giant mature fields to maximize their oil recovery. Field maturity in both well engineering and surface facilities will be the subject of next papers. The results have shown that, applying horizontal well drilling in giant mature fields is very crucial because of the horizontal well production improving factor (PIF), which represents the improvement of horizontal well production compared with vertical well production at the same locations, has been significantly increased. Horizontal well production improving factor (PIF) has increased with time along the reservoir life from pre-mature (virgin) to mature phases. In this study, it has increased from 1.23 to 1.28 during the last 9 years (2004-2012). However, simulation prediction results for next 9 years (2013-2021) have shown that, PIF has reached almost 5. That is because the oil column thickness become more thinner due to water movement through moving up toward the water oil contact and through high permeability streaks. As field practice, using pilot holes during drilling new infill and/or re-entry horizontal wells in mature oil fields is essential for successful high potential horizontal wells.