A Real Time Cloud-Based Transient Modeling of Wellbore Fluids Enabling Safer Deep Transient Testing

Abstract

Wellbore dynamics is one of the key factors in reservoir testing, acting as a bridge between the reservoir and surface measurements. The objective of this research is to address the challenges encountered in well control and highlight the outcomes of employing wellbore dynamic simulation to enhance the safety of formation tester (FT) sampling and deep transient tests (DTT) conducted in wells, with a special emphasis on pre-job simulations multi-parameter sensitivity analysis. This effort is geared towards advancing our comprehension of the interaction between hydrocarbons and wellbore mud during and following FT pump-out operations. The most recent advancement in DTT technology allows for the pumping of a larger volume of hydrocarbons into the wellbore, when compared to the operation of a conventional formation tester. While conducting DTT, formation fluids pumped from the well are mixed with drilling mud from the surface through a circulation sub into the annulus. This mixture of fluids is then circulated out from the annulus to the surface during the flowing period. It is imperative to possess a thorough comprehension of these procedures to ensure well control safety. Consequently, the utilization of a dynamic multiphase flow simulator that considers the interactions between downhole pumped hydrocarbons and drilling fluids becomes crucial to enhance the accuracy of pressure simulations during the DTT operation. Given the paramount importance of safety in oil and gas operations, a cloud-based wellbore dynamics simulator enables precise quantification of drilling fluid adjustments, circulation rates, hydrocarbon composition, downhole pump rates, well depth, hole diameter, overbalance pressure, and pump duration for various FT design sequences. This allows for accurate forecasting of downhole well pressure and the distribution of free gas throughout the well, adjusting these parameters as needed. Subsequently, we will explore scenarios with kick potential and risk mitigation strategies. This paper showcases a total of 15 case studies (different hydrocarbon types and overbalance scenarios), where cloud-based wellbore fluid simulations were performed for different flow rate scenarios, and to predict the potential well control situations. A special emphasis was given to the near critical hydrocarbon fluids such as condensate, volatile oil, and wet gas.