Acid Stimulation of Gas Wells with Severely Impaired Gravel Pack Completion - A Case Study of Mumbai Offshore

摘要

There were numerous challenges faced while performing stimulation jobs in an offshore gas field in India. The wells were completed without lift valves and there was issue of fluid recovery post stimulation. The reservoir consisted of poorly consolidated sandstone with high calcite context which rendered the conventional mud acid treatments useless. Moreover, the unconsolidated nature of reservoir made the plugging of core samples difficult and core flooding experiments practically impossible. Also, it was difficult to quantify the extent of formation damage due to absence of build-up study results. These issues were mitigated by careful analysis and effective utilization of data available at hand. The severity of damage and deliverability post stimulation was analyzed through nodal analysis. The type of formation damage was identified through intervention history and lab studies. XRD and solubility studies were performed to formulate the treatment fluid. Job designing and diversion was simulated using state of the art algorithms before executing and suitable means were followed for enhancing the flow back. This paper highlights the challenges encountered and the respective solutions executed and is a testament to how a simple yet systematic and well deliberated approach can sometimes revert production loss in complicated situations.