Publications

As the industry emphases on optimizing hydrocarbon production and reducing development cost, it has become important that the drilling risks are more holistically analyzed and understood. This paper focuses on the various risks identified, assessed and managed while planning a horizontal well in a complex geological setting in Offshore South East Asia. This was possible by adopting integrated risk management approach by reducing drilling and geological uncertainties. The objective was to drill through an overburden carbonate and sandstone reservoir section within oil producer to increase productivity. It was very important to understand the prevalent drilling risks in the study area and the mechanisms contributing to the risks for different formations. A fit for purpose risk ranking criteria has been developed for various drilling challenges. Based on the occurrence, impact and severity of various risks and resultant NPTs observed in the offset, the risk ratings were accordingly numbered and assigned to various challenges. The next step was to find fit for purpose mitigating solutions to potential drilling and geological risks in each planned well section. It was found that the risks involved in the overburden are the unconsolidated formations, geological uncertainty for geo-stopping above carbonate and fractured carbonates. The impact of occurrence of this risks is severe which can lead to total loss circulation with wellbore collapse eventually to well control situation. The risks anticipated in the reservoir section are drilling through weak rocks associated with thin coal layers and casing landing with horizontal entry into the main reservoir. The impact of occurrence of this risks is severe which can lead to mechanical failure and time dependent failure. This risk assessment and mitigation workflow resulted in reduction of potential high-risk events to low- or no-risk events by using technologies and services necessary to mitigate risks to acceptable and cost effective levels.