Recommendation of Counteractions for Prevention of Critical Events in Sub-Surface Drilling Environments

Introduction

Drilling a borehole is always guided by technical, economic and safety constraints. In the first instance safety plays a major role. Preventing crew, equipment and environment from injury, damage and pollution is a key focus. Equipment and instrumentation are inspected, tested and refurbished at regular intervals determined by a combination of risk assessment, local practices and legal requirements. Although this procedure provides a high degree of safety, the penetrated rock formations can always cause surprises that may lead to critical situations. Possible problems include influxes from high-pressure geological formations into the borehole, loss of circulation fluid into permeable zones or a drill pipe getting stuck in the borehole. These critical situations usually do not arise abruptly, but develop over time, and will escalate if they are not promptly detected and immediate counter measures are applied.

Figure 1 illustrates the general problem. The sketch shows the relationship between event uncertainty and hazard potential for an evolving crisis over time. Dotted lines indicate hazard potential levels in the case of early counteraction application. The hazard potential and probability for the actual occurrence of a crises increases with the delay in applying counter measures. Early indicators for a crisis are unclear and have a high uncertainty. Over time it becomes clearer whether we are dealing with an emerging crisis or not. But as the uncertainty about the state decreases, the hazard potential increases and makes the implementation of countermeasures more difficult and dangerous. Therefore it is crucial to detect critical events and decide on countermeasures as early as possible.

Figure 1.

Potential Hazard Detection

A decision support system (DSS) for these operations must involve the operational staff on the rig (drilling platform), on-site and remote analysts, and data-driven decision support processes that analyze available sensor data. In this paper we present such a decision support system for drilling operations using the example of stuck pipe problems. The approach presented in this work is part of a larger collaborative system for decision support developed within the European research project TRIDEC¹. This project focuses primarily on new approaches and technologies for intelligent geo-information management in complex and critical decision-making processes. The consortium² consists of 10 European partners from 6 countries, will be finished after 3 years in late 2013 and has a total budget of about 8.9 Mio. €³. TRIDEC is demonstrated in two scenarios, where both involve intelligent management of large volumes of data for critical decision-support. The first one concerns a large group of experts working collaboratively in crisis centers and government agencies using sensor networks for making critical decisions in evolving Tsunami crises. The other scenario – the one we are focusing on in this paper - concerns a large group of consulting engineers and financial analysts from energy companies working collaboratively in sub-surface drilling operations. Their common objective is to monitor drilling operations in real-time using sensor networks, optimize drilling processes and support the drilling companies to detect and prevent potentially critical system states.

Problem Statement And Related Work

The challenges in providing decision support for sub-surface drilling operations are twofold. On one hand there is the challenge of creating a decision support infrastructure that provides, among other things, resilient communication and collaboration mechanisms and adequate user interfaces. Another challenge is to implement intelligent machine learning components that are integrated into the DSS and provide valuable information to the end-users. In the following we describe the problems that we want to address with our proposed solutions.