Among the industry, is currently accepted that improper retrieval schedule of the core from bottom to the surface can result in either slow tripping speeds or the detrimental irreversible core damage due to the creation of microfractures.

The latter which is well-known as the gas-expansion core damage, is in reality worse as the core is not representative of the formation. In either case, high costs are incurred to the operators.

The primary aim of the project is to understand the mechanism of creation of the gas-expansion induced microfractures. To accomplish this, the essential macro and micro models are developed. In addition, using the results of the models, the core tripping process will be optimized based on the affecting factors including the core lithology, rock and fluid properties, etc.

Vibrations are caused by bit and drill string interaction with formations under ‎certain ‎drilling conditions. They are known as destructive loads and thus are leading to ‎downhole ‎fatigue failures, severe bottom hole ‎assembly and bit wear and may cause wellbore ‎instabilities. ‎Vibrations are affected by different parameters such as weight on bit, ‎rotary ‎speed, mud properties, bottom hole assembly and bit design as well as ‎formation ‎characteristics.

In this work the relationship between formation characteristics and drill string vibrations ‎in a ‎laboratory scale have been studied. Non-linear models have also been ‎built to ‎establish a relationship between different parameters.‎ A fully automated laboratory scale drilling rig, the CDC miniRig, was used to ‎conduct ‎experimental tests. A vibration sensor sub attached to the drill string, above the bit, ‎recorded ‎the drill string vibrations during the tests and additional sensors ‎recorded ‎the drilling ‎parameters.

It is ‎concluded ‎that the formations can be recognized in real-time by analyzing vibration ‎measurements. This allows to differentiate individual layers with different ‎strengths.

A gas-kick is a fundamentally transient event accompanied by many unknowns. Common approaches in kick modeling are based on the assumption of a more or less single “gas bubble” present in the annulus and slowly migrating upwards after shut-in. While this assumption satisfies straightforward volumetric well control aspects, it ignores species transport and chemical reaction kinetics leading to drill string corrosion.

The intention in this project was to make no a-priory assumptions regarding the evolving flow field. Instead focus was put on a spatially highly resolved model covering the near bottom-hole section of the wellbore where two-phase interactions could be observed at a close-up view.

The project illustrates the value of CFD simulations to verify flow conditions and to support the design process of new measurement tools for early kick detection.

Around the globe, every day several hundreds of oil and gas wells are being drilled. All these wells face different challenges but have one thing in common. They all have the potential for well control incidents which can affect the crew, the rig and the environment. This project aims to develop a downhole sensor package which allows kick detection in real time utilizing high speed telemetry systems. This will significantly reduce the reaction time on well control events.

In this project, high sensitivity sensors will be evaluated for downhole kick detection. Influencing parameters such as cutting size and distribution, temperature and vibration effects among other variables affecting the sensor performance will be investigated. Based on the initial evaluation, using CFD modelling, an optimized prototype of a sensor package will be designed and tested.

Drilling programs continue to push into new and more complex environments. As a result, accurate measurements of drilling data in real time are becoming more critical by means of minimizing the risks as well as the costs. The determination of the actual wellbore shape in real-time can be considered as one of the key components to detect problems such as borehole instability.

The scope of this project was to develop an ultrasonic caliper tool for borehole geometrical measurement and developing an additional ultrasonic sensor to record the speed of sound in the drilling fluid at the desired depth. Measurements were performed in artificial wellbores with geometrical anomalies.

Numerical simulation of the measurements and comparison of the simulated results gave estimations how accurate the data was. It could be shown that anomalies can be detected with an appropriate accuracy if circle fitting methods in combination with robust error models are applied.

It is agreed that mitigating the impact of the kick and lost circulation on the drilling operation requires an efficient system, which helps to detect the kick and losses as early as possible to be able to take the necessary action on time. Continuously monitoring the drilling fluid surface and velocity inside the bell nipple might be the quickest surface measurement to detect loss and kick events.

Therefore, the main objective of this project is to develop a new concept for detecting kick and loss in the shortest possible time by using the bell nipple as a place to install the required instruments and measure the related parameters.

Justified by reported incidents, the role of wellbore cement being a competent barrier for up-hole hydrocarbon flow is questioned in many cases. In particular it is not clear whether the integrity of the bond and seal between cement and formation or cement and steel-casing is given over the life-cycle of well operations and beyond.

This research intends to find answers to possible destructive consequences of different life-time loads by studying the effects of casing micro movements, chemical interactions and corrosion and operational induced shock loads. To achieve this goal, special test procedures and equipment will be developed and experiments are to be conducted. The experimental observations will be compared to finite element / finite differences modeling results for validation.

The outcome of this research will allow to classify the risk of mature wellbores to develop integrity issues and to provide suggestions to avoid cement barriere failures.

Shale gas and oil projects require large drilling campaigns: This includes drilling numerous wells continuously for a sustained production. The major change in the industry was to go from “handmade” to a “mass market” of wells. This requires an entirely different approach to optimize operations for an entire field.

This research targets exactly the optimization of all the operations by integrating all the disciplines from land, drilling, completion, production and logistics and finding the best possible way and means for this “factory” to operate efficiently.