Evaluating Dynamic Oil Well Behavior Using Transient Simulator: Case Study - Northern Iraqi Oil Field

Understanding the well behavior during shut-in and startup period will give a clear idea about future production performance from brown fields. In mature oil fields, there is a significant increase in the water-cut with a certain decrease in reservoir pressure especially ones experiencing active water drive or water injection. This study came to investigate the challenge during the startup of some wells, which are known as lazy wells. Once these wells are shut-in, they will not startup naturally without an intervention process (such as swabbing, nitrogen injection, etc). The oil well X is located in northern Iraq; it showed significant reduction in production due to many years being on production. The well was flowed successfully after a scheduled shut-in for two months to allow for reservoir pressure recovery in the near wellbore area. In this study, a dynamic wellbore model was built to investigate the well performance under different transient conditions (e.g. Shut-in and Startup) and the feasibility to put the well on production again after shut-in period with zero intervention methods. Additionally, Nitrogen lift is implemented to kick off the production from this well and effect of water cut rise on well dynamics were studied. Results showed that the well is in a critical situation where slight drop in overall production system pressure will cease production. Using Dynamic wellbore models and ultimately coupling them with dynamic numerical reservoir models provides oil and gas field operators with great insight to their wells and their different behaviors during various transient conditions thus cost cutting any unscheduled production drops.