Research Projects of All Chairs
Innovative Coring Concept for Exploration Drilling
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.
Data and Expert Driven Workflow for Application of Automatic Adaptive Algorithm in Well Operations
Data and Expert Driven Workflow for Application of Automatic Adaptive Algorithm in Well Operations
In today's data extensive world, the oil and gas industry has been evolving by developing advanced diagnostics and optimization tools based on artificial intelligence techniques that are data driven. Most autonomous workflows are built on a foundation of statistical analysis and the implementation of artificial intelligence techniques based on real-time data, without the integration of reservoir/well models. However, this raises the crucial questions of how to predict critical dynamical conditions when the well requires long term actions (workover, sand control, chemical application, etc.) and how to maintain optimal well conditions.
Thus far, the Automatic Adaptive Algorithm (A3) is an innovative concept of smart diagnostic and well performance optimization based on real-time data and guidelines. The research focuses on avoiding problems with downhole equipment and excessive sand production by allowing condition monitoring of downhole equipment to keep the production rate, pressures, and temperature at an optimum level.
The proper regulations could help the industry increase the production of low productivity wells according to the conditions in the well/reservoir and prevent premature failures of downhole equipment.
A Method and System for Detecting Undesirable Drilling Events
In order to mitigate the impact of undesirable events during drilling, it is important to efficiently detect them as early as possible to take the necessary action on time. The three main surface parameters used to detect kicks and losses are mud pit volume, return flow rate and standpipe pressure. Of these three parameters, the outflow rate is known to be the best and fastest source for identifying the problems. Thus, the necessary measurement devices are traditionally mounted on the return flowline.
In contrast to the conventional approach, performing the measurements already at the bell nipple or marine riser may be the better solution. By continuously monitoring the drilling fluid’s level, velocity, density and viscosity inside the bell nipple/marine riser, the results are delivered faster and more exact compared to taking the measurements in the flowline.
The main objective of this project is to develop a new and time-efficient concept for real time detection and verification of the most common undesirable drilling events. Therefore, to more effectively detect and verify losses, kicks, stuck-pipe, string failure and wellbore instability, the location of the relevant equipment can be optimized to the bell nipple.
Analysis of Drill String Dynamic Behavior
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.
CFD Analysis of Gas Kick Scenarios
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.
Error Analysis and Estimation of Real-Time Drilling Data and Operations
In modern society, digitalization is the key to a company’s survival. Many oil and gas companies are currently implementing digitalization initiatives, but struggle to leverage the full potential of the technology. To do so, a holistic understanding of the complex interactions and dependencies of all involved technologies and operations is required. Therefore an in-depth process chain analysis from initial planning to the final decision making is carried out to identify the shortcommings of the current design and to develop comprehensive solutions.
Real Time Wellbore Instability Detection using Ultrasonic
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.
Long-term Cement Integrity
As justified by reported incidents, the role of wellbore cement being a competent barrier for up-hole hydrocarbon flow is questionable. In particular, it is not clear whether the integrity of the bond and seal between the cement and formation or cement and steel-casing is sustained throughout the lifecycle of well operations and beyond.
The cement/casing and cement/rock interface of a cemented annulus is a brittle material-composite. During well operations the bond is subject to static and dynamic stress loads. The risk of bond failure depends on the load frequency, its magnitude, and intrinsic properties of the bond between the cement and casing, as well as the cement and rock.
This research project proposes to apply a certain low number of stress cycles on a cement/casing and cement/rock annular composite to evaluate the low cycle fatigue strength of the bond. Hence, innovative laboratory fatigue testing concepts will be developed in parallel with cutting edge testing apparatus. This will allow the application of static and dynamic axial loads (compression/tension) on an annular cement/casing and cement/rock bond. The experimental results will be compared to finite element/finite differences modeling results for validation.
Operations Optimization for Shale Assets
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.
Real-Time Monitoring of the Effect of CO2 on the Cement Sheath
Global warming is one of the biggest issues the world is facing. Capturing CO2 from the atmosphere and storing it in geological formations can help counteract climate change. Nevertheless, its interaction with well barrier elements such as cement, casing, tubulars, packers and valves can lead to possible leakages. During CO2 sequestration, CO2 is injected into a geological formation in its super critical state. The super critical CO2 can corrode steel and elastomers and react with the calcium compounds in the cement, dissolving them and forming calcium carbonate and bicarbonate in the process. This can lead to channels forming on the cement-to-rock interface or cracking due to the carbonate precipitation, resulting in a loss of well integrity.
The aim of this study is to find ways to continuously monitor the integrity of wellbore cement under in-situ conditions. For this purpose, an autoclave, able to withstand the CO2 in its supercritical state, has been constructed. This autoclave also facilitates CT-scans of the pressurized sample, as well as acoustic measurements, using state-of-the-art piezo elements. The first tests will be done using neat Class G Portland cement, to verify the design and sensors. The test set-up consists of a rock core with a channel in the middle to ensure an even distribution of CO2, which will be cemented into the autoclave-cell. Once the ability of the sensors to monitor the integrity is verified, different cement compositions and their interaction with supercritical CO2 will be studied.
The experimental setup and the procedure discussed closely simulate the downhole condition. Hence, the results obtained using this setup and procedure are representative of what could be observed downhole. The cement sample is not removed from the cell and is analyzed under in-situ conditions; digitalization powers the in-situ analysis in this experiment. In addition, the effect of rock permeability is also considered and included in this study. The results from this study can be used to prevent leakage of CO2 to the environment and/or other formations and nullify the disadvantages of CO2 sequestration. This should improve the economics of these wells as well as the health, safety and environment.
BEER: Bio Enhanced Energy Recovery
Bio Enhanced Energy Recovery is a system developed by the Chair in cooperation with leading industry partners in Austria and Germany. BEER represents the solution on the imminent needs for environmentally conscious energy recovery methods in geothermal reservoirs. All applied components are non-hazardous and most are even used within farming and food industries.
BEER is currently undergoing the first field tests and results will become available soon. The BEER technology is based on numerous pending patents.
SCALING: Ways to Reduce Production Limitations
Scaling is one of the most problematic issues with energy production from reservoirs. Originating from hydrocarbons, formation waters, or from combinations of fluids, salts, and bacteria form barriers which reduce or stop the energy flow to the surface. Not only subsurface installations are affected, but surface installations as well.
The researchers of the Chair focus on applying physics rather than chemistry with significant success. This is not only positively influencing the production performance, it is also contributing to increased environmental care and reduced CO2 footprints.
ThermoDrill: A Novel System for Geothermal Projects
Costs of erecting wells for Deep Geothermal Applications represent a major part of the overall investment. Particularly when facing hard, crystalline rocks, the ROP becomes very low. To allow for better performance and such for easier risk assessment, an innovative technology is developed to provide much higher ROPs.
A combination of the rotary drilling technology with jetting technologies offers great opportunities for improving the drilling performance and reducing the need for fracturing.
Application of Alternative Material as Sucker Rod Strings
Application of Alternative Material as Sucker Rod Strings
Sucker Rod Pumps are the most common form of Artificial Lift Systems used in wellbores to improve the production rate. Within this system, the sucker rod string is the connection between the downhole pump and the surface drive unit. The aim of this project is to investigate the application of alternative materials and designs, as well as to analyze their practicality in comparison to the current conventional rod strings. Tests are planned to be conducted at the Pump Testing Facility at Montanuniversität Leoben, where a new test stand for this particular purpose is planned to be built. A successful replacement to conventional strings could lead to less structural loads, more efficient pumping, safer operations and an increase in the mean time between failures.
Artificial Lift System Performance Optimization & Cost Reduction
Artificial Lift System Performance Optimization & Cost Reduction
The main targets of this project are to increase of the meantime between failures of the sucker rod pumping system as well as the stress reduction of system components. Other targets include the reduction of electricity consumption and the implementation of a monitoring real time diagnosis system, to further establish a predictive maintenance/failure prediction system.
Due to successful projects in the past, Sucker Rod Anti-Buckling System (SRABS) and Energy Efficiency (EnEff), research in the optimization of sucker rod pumps is ongoing. SRABS investigated the behavior of the subsurface components of sucker rod pumping systems with a strong emphasis on buckling. Whilst EnEff investigated the behavior of surface equipment of a sucker rod pumping system. Efficiencies and mechanical loadings can be evaluated through the measurements of current and voltage at the electricity supply grid. Other contributing aspects include the position of gear reducer shaft and walking beam, as well as the load at the polished rod and fluid pressures of a variable speed drive (VSD) driven system.
- A high optimization potential for sucker rod pumping installation has been shown in tests at the Pump Testing Facility, the recent field test and previous projects (SRABS and EnEff). Improvements and optimizations will increase the meantime between failures (MTBF). Additionally, the effective usage of electrical energy and reduction of installed converter hardware will contribute to a more positive environmental footprint along with a cost reduction.
- The goal of the project is to establish an efficiency monitoring system to detect, identify and understand undesirable situations, as well as conditions within the sucker rod pumping system.
- The monitoring system incorporates an upfront system optimization and continuous improvement during operation. Predictive maintenance is employed to analyze and evaluate the data gained by the monitoring system, as well as to increase the meantime between failures and useful life of system components. To do so predictive modelling is based on highly sophisticated mathematical models like neural networks.
Downhole Dynamometer Sensors (DDS)
The continuing trend towards digitalization in the oil and gas industry is the field operators’ reaction to the market’s demand of reducing operating costs and increasing the lifetime of equipment. Advanced technology and procedures are essential to reach these goals. Sucker rod pumps (SRP) are a standard Artificial Lift System for liquids in mature fields and for the dewatering of gas wells. This type of lifting technology is well known and successfully used all over the world. However, previous developments during the last century were unable to prevent the system from failing under certain conditions. Several SRP failure analyses have shown that a significant fraction of system failures are the result of a broken rod string, caused by overloading or buckling. A major aspect that deters innovation is the lack of downhole data, which can be replaced using the DDS measurement system. This system consists of multiple DDS that are placed at specified positions along the sucker rod string. Each DDS records a three-dimensional stress field and motion profile of the sucker rod string, as well as the temperature of the produced liquid.
The data recorded allows for an extensive evaluation of rod string behavior. Aspects such as: rod string movement and loading, friction forces between rod guides and tubing, fluid pressure, rod torque, and volumetric parameters can be processed. The recording of several sensors is linked together to provide a comprehensive picture of the sucker rod string’s condition. The complementation of the value chain is achieved by using the recorded information to update rod string simulations. Nowadays, models for predicting the dynamic motion of the sucker rod string in the tubing string are available. Nevertheless, their accuracy depends on a variety of parameters, like friction and damping coefficients that are associated with the individual installation. To achieve a more stable design, data measured from the well to be optimized must be obtained. The meantime between failure (MTBF) can be increased significantly particularly in problem wells suffering from issues such as under paraffin precipitation or high complex geometry. Since the chair began developing the DDS in 2012, several field applications have been accomplished. Currently, the upgrading and implementation of additional features for the sensors is taking place.
Hydraulic Pump Development
Conventional Artificial Lift Systems are limited by their application with regard to depth, borehole trajectory, and chemistry of the produced media. The new hydraulic pumping system overcomes these limitations and assures a cost-effective production in harsh environments as well as low gravity oil reservoirs. The pumping system consists of a specially designed pump and piston combination, which is driven by a hydraulic pressure unit from the surface, without any mechanical connection. This new pump type has been designed, manufactured, and tested at Montanuniversität Leoben, Austria. To speed up the design process, the pumping concept of the hydraulic subsurface pump is validated using the open-source software toolbox.
Pump Testing Facility
Low oil prices push the demand for efficient production, especially in mature fields. Reducing the costs of artificial lifting by increasing efficiency is mandatory for extending meantime between failure, economic limit and increasing recovery factor.
For achieving these goals the Pump Testing Facility was established, to allow low risk, low cost, and high performance testing of new technologies, including various artificial lift systems. Montanuniversität Leoben constructed this facility to overcome the enormous field testing costs and to speed up innovation. The testing facility is able to test oil field equipment under conditions occurring in depths up to 500m.
As an integral part of the chair’s research programs, new technologies, self-developments and patents will be tested before being applied in fields. The pump testing facility is used to provide services to the industry and to test according to industry needs. In close cooperation with the industry, this pump testing facility will be expanded to cover more special operational modes and events that may occur in the field.
Sucker Rod Anti-Buckling System
During times of low oil prices, cost optimization is vital. Especially in mature oil fields, the reduction of lifting costs by increasing the mean time between failure and the overall efficiency helps stay economical and increases the final recovery factor. Today a significant portion of artificially lifted wells use sucker rod pumping systems. Although its efficiency is in the upper range, compared to other Artificial Lift Systems, there is room for improvement and system optimization. The Sucker Rod Anti-Buckling System (SRABS) keeps the entire rod string under tension using technology based on a redesign of the standing valve and the advantageous use of the dynamic liquid level. This results in complete buckling prevention and a reduction in the overall stress in the sucker rod string. The pump is already field tested and previous experience is being implemented into the design of the new pump type.
Sucker Rod Pump Valve Movement Analysis
Investigations have shown that ball valves of sucker rod pumping systems open and close not only at the lower and upper dead center, but also in between, depending on the stroke characteristics. This fact can influence the volumetric efficiency and wear of the ball and seat significantly. To find a solution to this problem, two major points need to be solved – understanding the movement of the ball valves and the exact motion of the downhole plunger.
In the past, extensive simulation efforts were spent to describe the motion of the standing and traveling valves of the sucker rod pump. The simulation performed by AC2T has shown very promising results. Unfortunately, the model needs to be verified in order to continue. This project enables the verification of the existing CFD model.
Virtual Flow Meter Project
Nowadays, digital transformation is no longer an option that only few global players choose to pursue – it is becoming an integral part of almost every company’s portfolio. Together with various industry partners, the Chair of Petroleum and Geothermal Energy Recovery has joined the journey towards digital transformation. In a current project, a virtual flow meter is being developed to greatly aid in obtaining a deeper understanding of hydrocarbon flows. By applying concepts of machine learning, this virtual measurement device will be able to adapt to changing boundary conditions in the field, whilst simultaneously maintaining its accuracy and flexibility. To simulate various field conditions for the tool’s learning capabilities, three-phase experiments at ideal conditions are being conducted at the chair’s unique pump testing facility. The virtual flow meter will not only lower the operational cost, but also improve the decision-making process based on artificial intelligence applied in the field.
In the project we focus on the coupling of flow and geomechanics in naturally fractured reservoirs. The final goal is to model CO2 injection in fractured reservoirs with pre-existing faults and to estimate the effect of mechanics on flow and on storage capacity as well as estimating the risk of leakage and fault activation.
Underground Hydrogen Storage
Underground hydrogen storage is a promising way to store excess renewable energy with sufficient storage capacity. The Reservoir Engineering group participates in a pilot project assessing the feasibility of large-scale hydrogen storage in a depleeted gas field in Upper Austria. Our aim is to assess chemical interactions between the reservoir and the injected hydrogen/methane mixture and to simulate the injection and production processes in order to predict the quality of the backproduced gas. For the future we plan to extend the study to microbial activity and its impact on hydrogen storage and conversion operations.
Development of Low-cost EOR Methods
We develop a combined experimental/numerical workflow to provide solutions for Improved & Enhanced Oil Recovery (IOR/EOR). We aim for fundamental understanding of IOR/EOR methods across the scales (from the pore to field scale) and for solutions tailored to the development of individual fields. For this purpose we currently establish a laboratory for the investigation of interfacial properties (fluid-fluid and rock-fluid) and core flooding supported by Imaging methods such as micro and medical Computerized Tomography. In parallel we develop the numerical tools that are neeted for data interpretation and upscaling, resulting in a combined numerical/experimental workflow.
Wavelet-based Multiresolution Upscaling of Porous Media
We utilize the multiresolution framework of wavelet analysis that has been developed for image processing in order to develop a novel method for numerical upscaling of porous media flow. For this, equivalent rock properties are generated from the geologic fine-scale models via wavelet analysis making use of structured and unstructured grid representations. The wavelet method is well suited for upscaling rock properties and especially if spatially correlated heterogeneity is present. With this project we aim to significantly improve the performance of numerical upscaling with respect to accuracy and computational costs.