Nanomaterials are the new additives for drilling fluids that can improve its properties and eliminate problems due to increased downtime and well costs. The objective of this research is to select the optimum concentration of nanoparticles that enhance drilling fluid properties and hydraulics. This study investigates the effects of commercially available nanoparticles on the rheological and filtration properties and optimizes the hydraulics of water-based drilling fluids. In this study, the samples were prepared as water-based muds with and without various concentrations of 5.7 nm colloidal silica dioxide nanoparticles. Series of laboratory experiments were carried out for all samples using standard API Low Pressure Low Temperature (LPLT) filtration and rheological tests. Two mud systems at different pH conditions were used to evaluate the impact of nanoparticles. A commercial software was used to evaluate the impact of the nanoparticles on the Equivalent Circulation Density (ECD) and the circulation pressure loss in a deviated wellbore. Results show enhancements in the rheological and filtration properties for water-based muds treated by the nanoparticles used in this study with concentrations below 0.7% by weight. Furthermore, the results show the ability of these nanoparticles to make the filter cake consistent, compacted, and thin. The results reflect the negative impact of the nanoparticles with concentrations above 0.7% by weight on some of the rheological properties. The optimum nanomaterial concentrations with the best properties were observed as (0.1%-0.3%) by weight. Furthermore, the concentration of 0.1% by weight reflected the significant reduction in the ECD and the circulating pressure loss. Nanoparticles used in this research can play a vital role in reducing drilling problems. Multilateral wells, slim holes and deep horizontal wells can be drilled by using water-based mud with the addition of proper nanoparticles and eliminating the need for oil-based muds that are expensive and environmentally unacceptable. However, it is critical to select the proper size and concentration of nanoparticles in order to eliminate its negative impact on the drilling fluid properties.

Objective of this study is to shed light to critical well control parameters of horizontal shale gas wells drilled with oil based muds (OBM). This study utilizes an interactive well control simulator to re-evaluate the kick control procedures in water based mud (WBM) and verify its application to oil based mud. Due to gas solubility in OBM a real time drilling and hydraulics data analysis is essential to minimize kick volumes. Therefore, early kick detection and surface warning signs are critical to minimize the influx size and reduce wellbore pressures. Moreover, the impacts of water-to-oil ratio, gas solubility, kick size, influx type and circulation rates on well control are investigated. OBM kick control process in horizontal wells creates additional challenges since the surface pressure and volume are not representative of the bottom-hole conditions. In unconventional shale gas reservoirs, oil and synthetic based drilling fluids are very common. Drilling cost, log interpretation, and environmental impacts are the main drawbacks of OBM. However, wellbore stability, reduction in torque and drag, stability of mud properties at higher temperatures and better drilling performance are the main advantages of OBM. Preliminary results show that dissolved gas in oil is liberated at the bubble point pressure and complicates surface kick handling procedures. Choke adjustment is hard due to the unexpected high volume of gases released and the delay time of choke response. Early detection is a key factor in minimizing the influx size and properly controls the casing shoe and choke pressures. Based on 110 hours of real time interactive simulation, influence of gas solubility on well control in OBM is presented to improve rig and personnel safety and reduce the blowout associated risks.

The current state of the drilling industry tends to focus on technology and techniques that reduce the cost of well construction. One approach is to use drilling automation to help improve ROP, and perhaps more importantly, to mitigate drilling dysfunctions and human errors than can lead to large, unplanned expenses. SPE's Drilling Systems Automation Technical Section (DSATS) created an international university competition to encourage the development of new drilling algorithms and to get more young people involved in drilling. The students must design, build and operate a small (6 ft / 2 m) drilling rig with fully automated sensors and controls. They drill a specially created, multi-layered rock sample as fast and as straight as possible, with only two buttons: start and stop. This paper summarizes the work done by the West Virginia University team that won the 2016 competition. It shows scalable drilling algorithms can be developed on a miniature rig that can later be transferred to ongoing drilling programs. DSATS implemented a competition to encourage students to investigate the use of automation techniques and tools for drilling systems. The competition fosters a greater understanding of complicated drilling systems, challenging students across disciplines to consider the possibilities of a career in upstream drilling operations. This project requires each university team to first submit a proposal, including structural design, control architecture, and sensor selection with no knowledge of the material to be drilled. Teams were advised to consider mitigating the effect of nonplanar junctions as well as the possibility of lost circulation, and to be especially cognizant of vibration and torque issues. The winning team received a travel grant to attend the ATCE to present their test results at the DSATS symposium in Dubai. This paper addresses the details of that presentation. It includes: Drilling limitations and critical parametersConstruction issues and initial operations that required a re-designFinal design criteria, constraints, tradeoffsSummary of recorded data and key eventsDrilling parameters and how they impacted the testEconomic considerationsSignificant lessons learnedConclusions and recommendations As the competition finishes its second year, it remains the only competition of its kind that requires a multidisciplinary approach at a university level, and prepares those involved for the type of interwoven, team approach often at the heart of oilfield operations today. While the rig designs are practical, they are not limited by historical features or commonplace rig designs. Hands-free drilling is possible and proven on a small scale as more and more companies begin to implement full scale operations to mitigate drilling dysfunctions and improve ROP to lower costs.

Challenges associated with Utica and Marcellus shale well integrity and safety necessities further study in order to have an effective and economic drilling operations. Objectives of this comparative study are to evaluate the impact of unscheduled well control events on wellbore integrity, as well as the influence of poor drilling practices that trigger well control emergencies in shale gas wells. A realistic multiphase simulator is used to evaluate well control unexpected scenarios in Utica and Marcellus shales. Changing operational parameters such as wellbore profile, well control method, drilling fluid type and circulation rate in Marcellus and Utica horizontal wells are investigated. Further, this research studied the impact of influx type, size and intensity on well integrity. Behavior of dry gas, rich condensate and black oil influxes are compared in extended lateral wells. The impact of free gas migration in inclined downward laterals drilled with water based mud is compared to the influence of gas solubility in inclined upward wells drilled using synthetic oil based mud. Preliminary results show that deeper, over-pressurized Utica shale presents more challenges compared to Marcellus shale wells. When oil based muds are used additional challenges are presented since the surface pressures and volumes are not representative of the bottom-hole conditions. Dissolved gas in oil is liberated at the bubble point pressure complicating surface kick handling procedures. Gas influx migrates and reaches surface much quicker in water based muds and inclined downward laterals. Higher the influx circulation rate, size and intensity, higher the resultant pressures and volumes and higher the risk of exceeding casing shoe fracture pressure and risking well integrity. Drilling fluid type, properties and flow characteristics are critical for well integrity. Early detection is a key factor in minimizing kick size and properly contain pressures without violating safety and environment regulations and reduces the blowout associated risks. Accordingly, well integrity is verified by monitoring surface choke, casing shoe and constant bottomhole pressures throughout the entire well control operations.

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