Gas solubility in Oil-based Mud and it's effect on kick detection: NZ19 case

Abstract

SONATRACH as the largest petroleum company in Algeria and Africa, it has moved to explore unconventional recourses, in order to increase proven oil & gas reserves. SONATRACH has started a new project of tight & shale gas, deep water exploration and also exploration in north Algeria. In these areas the risk and the cost are rising up, SONATRACH has to drill more deep and complex wells in these challenging areas where the risk of kicks and blowouts are commonly existing, wich can lead to catastrophic consequences. As a part of our master’s degree research in the drilling engineering department at University of Kasdi Merbah Ouargla, we have conducted a study of gas behaviours and its effects on kicks prevention in the concept of well control modeling & simulation which is necessary in oil & gas industry, where the kicks represent one of the biggest issues since it can lead to well integrity failure resulting human life loss, environment and equipment damage. However, extensive studies have been conducted on modeling and simulation of kicks behavior. These models are a valuable tool for well design, the evaluation of well control procedures and also for rig personnel training since personal can be trained on a simulator and not on real wells. In this study, we carried out an extensive review of historical kick events in SONATRACH Company from 2009 to 2012. This study provides the context of the importance of well control modeling and simulation. Some of the common existing well control models in open literature are presented. In this case study, most of the simulation runs are based on the well NZ19, this simulation was realized by a commercial software Drillbench© to study the effect of different parameters on the solubility of gas in the drilling fluids and the wellbore pressure. In the simulation results: we summarized the influence of several factors on the solubility of gas in the drilling fluids and the wellbore pressure. We have noticed that if all parameters that they contribute to the successful completion of wells will be optimized, it certainly many incidents can be avoided during operations.