The oil and gas well construction is often associated with the unknowns and uncertainties while executing the operations. Because, while drilling, the drilling bit is under the ground where the information is usually gained through interpreting several surface and downhole sensors. Considering the lack of direct access to and visual of the downhole in real-time, the information from these sensors is vital to carry out safe and engineered operations. Typically, these sensors relay basic information such as the pressure in the pipes via a pressure transducer, the weight of the pipes via load transducer, etc. In the well construction process, there are many events where data is not collected or merely the quality is less than desired. Recent want of automation of the well construction process of several oil and gas companies showed the advance and amount of the existing sensors is inadequate. There is a need for more advanced sensors to collect meaningful data and more advanced materials while constructing the well. In the process of well construction, there are many events that the sensors are not used and no data is collected. At the recent years, the oil and gas industry showed a keen interest in automation of the well construction. Researchers started to seek advanced sensors to automate the parts of the process, for example, automation of drilling fluid measurements, automation of pipe handling, etc. An example of drilling fluid measurement automation sensors and materials is presented. The results of this recent successful endeavor motioned the need for more emphasis on the advanced sensors and materials for well construction. In this chapter, the authors are providing a review of select relatively advanced materials and sensors in various disciplines in well construction. The oil and gas industry needs a stronger highlight on the better, advanced sensors and materials to carry out the operations safely and systematically. We hope that this review will increase awareness in the industry to gain more insight into the advanced sensors and materials and use them to accomplish safe and optimized operations.

Fluids used during well construction operations serve as a primary barrier for well control, with the fluid density generating sufficient hydrostatic pressure in the fluid column to control downhole formation fluids and gas. Realtime density measurement at the well inlet, where high pressures of many thousands of psi can occur, is highly desirable in order to maintain well control. This improved characterization of the well bore pressure profile allows one to drill wells with narrow drilling margins without non-productive time from well control events, resulting in safer and more cost-effective well construction operations. Gamma ray densitometers are suitable measuring devices for high-pressure density measurement. Typical flow conditions encountered at the inlet, such as a fully filled pipe and a homogeneously mixed mud, are very conducive to their use. In-spite of their high measurement accuracy and relatively fast response times, however, these meters have seen limited adoption in field. This is primarily because the meters come with safety concerns due to the radioactive source required for gamma ray generation. Additionally, the source has to be tracked throughout its life and properly handled during storage, transportation, installation and disposal. Given these concerns and challenges, a majority of oil and gas operating and service companies use manual density measurements at the mud pits using a pressurized mud balance. To help change this rather antiquated and infrequent practice that relies on manual labor, this paper evaluates the feasibility of using a non-radioactive, X-ray based densitometer as an alternative to the gamma ray meter. X-ray densitometry works on the same proven principles as gamma ray densitometry, without the latter's drawbacks. Two X-ray methods, an empirical method and a model-based method (inspired by a technique used in the medical field known as single X-ray absorptiometry) are presented here. Real-time density measurements on the high pressure line with an accuracy of 99% or better and a measurement frequency of 1 Hz are feasible using these methods.

With a myriad of flow and density sensors available, it can be difficult to decide on the right metering technology to make density and mass flow rate measurements, that suits both application and cost requirements. Operational specifications listed in product brochures typically apply to tests done under highly controlled conditions and generally fail to account for the extreme variability in flow conditions of drilling and completions fluids in the real world. Thus, time and other resources can be wasted by the end users in trying to validate the various meters. Even when right metering technology is selected the measured values often have low accuracy and low measurement frequency. The intent of this paper is to provide a high level overview of the working principles of some of the main-stream metering technologies, identify applications they are well suited for, clarify their limitations, and provide an overview into current research to address these limitations. The paper will allow the reader to narrow down options for appropriate density and flow metering solutions for particular applications, and at the same time highlight the gaps and needs that need to be addressed by further research and development. The paper also discusses an X-ray based metering technology that overcomes some of the disadvantages and deficiencies of established meters. Recent work on characterizing the drilling fluid density and flow rate at the high pressure well inlet using X-rays has shown that these measurements can now be made with greater than 99% accuracy and at 1 Hz measurement frequency. Such level of accuracy and measurement frequency is not offered by any of the mainstream metering technologies. It is expected that the X-ray based technology when implemented will lead to a step-change improvement in current density and delta flow (flow in - flow out) assessment, and will thereby positively contribute to improved hydraulics management, better and earlier kick detection, and further enhanced managed pressure drilling control. In this paper we build upon the existing work on X-ray based density and flow rate measurements of drilling fluids. Specifically, we discuss preliminary work towards development of a new flow measurement technique which can measure flow rate using an X-ray flat panel detector. Using a flat panel detector offers a cheaper alternative to the existing high speed imaging based flow measurement methods. We also share results from a method developed for real-time calibration of the X-ray detectors. Using the calibration method X-ray measurements are shown to have a repeatability of greater than 99%. A section is also dedicated to characterizing the intensity output from the X-ray source. Finally, we show that X-ray density measurements conducted with static fluids in existing literature remain unaffected when the same density fluid flows through a pipe.

Managed Pressure Drilling (MPD) allows one to drill through formations with narrow pressure windows, thereby making those formations that cannot be drilled with conventional techniques accessible. It also provides the capability for early detection and safer handling of well control events. This technique requires accurate estimation of the annular pressure profile and the delta mass flow rate. These measurements can be improved through accurate density and mass flow rate measurement at the high pressure (7500 psi) input side of the well. Since no good metering technologies exist to make these measurements, the objective was to develop a high pressure density and mass flow rate sensor. A comprehensive review of all existing flow rate and density measurement instruments suggested that an X-ray based sensor was the best option for the high pressure fluid line. Multiple experiments were conducted to determine the electrical power range (voltage and power) for the X-ray tube that would work best for mud between densities in the range of 8 to 20 ppg. Experiments were then conducted to test the accuracy and feasibility of techniques developed for density and volumetric flow rate measurement. Based on these experiments, an X-ray source and detector were identified and a sensor was designed for inline use on 4 inch pipes. Two approaches were developed to estimate density using the sensor. The first was an empirical approach where sensor gray level values were directly mapped onto mud density values though in laboratory experiments. These mappings can then be used in the field to estimate density. The second was a model-based approach that estimates density based on the Beer Lambert's law. Both these approaches were tested experimentally using drilling muds of different densities and compositions. A mechanism that uses X-rays to determine volumetric flow rate was also designed and tested using both simulations and experiments. A real-time calibration subsystem had to be added to the sensor to preserve measurement accuracy and precision over time. Based on encouraging results from simulations and experiments, a laboratory prototype was built and is currently undergoing flow loop tests. This is the first time an X-ray mass flow rate measurement sensor has been designed to be used on high pressure lines. Preliminary findings indicate that no existing sensors used for similar applications can match the measurement accuracy and frequency that may be offered by this technology. Development of this sensor would improve the safe drilling of complex wells with narrow drilling windows.

Accurately measuring mass flow rate in real-time at the well inlet where pressures can approach 7500 psi has rem ain d elusive. Drilling contractors still primarily rely on the antiquated pressurized mud density cup and the pump stroke counter for this “measurement” of flow into the wel l. Gamma ray densitometer is a potential solution, but its u se has been limited due to its radioactive source and slow resp onse times. A metering technology that shows good performance is the continuously excited clamp-on transit time ultrason ic flowmeter. However, the meter accuracy is in a 95-9 % range and deteriorates at low flow rates. Past efforts to commercialize low-cost / low-pressure x-ray technology, for use i n downstream oil and gas, which is based on proven ga mma ray principles have also been unsuccessful. However, ad vances in novel materials and measurement technologies are now making it possible for us to re-visit relatively lo w cost x-ray mass flow rate measurement systems. These systems can provide real-time mass flow rate (i.e. density and flow rate) measurements with 99% accuracy and 1 Hz frequ ency. This paper discusses how new x-ray technology can b e used to make such higher frequency and high accuracy real-t ime mass flow rate measurements. Details of extensive lab me asurements and considerations for field application will be sh ared in this paper. It is expected that the technology when impl e ented will be a step-change improvement in current delta flow (flow in – flow out) assessment and will positively contribute to early kick detection and managed pressure drilling control. Introduction High cost operations such as deepwater well constru ction can greatly benefit from higher accuracy and higher frequency inlet mass flow-rate measurements, particularly if measurement data can be obtained at an accuracy of 99% or great er and at a frequency of 1 Hz. Improved mass flow rate (density x volumetric flow rate (VFR)) measurements can lead t o improved real-time estimation of delta flow rate, t he difference between flow out and flow into the well, which is o ne of the primary indicators for trouble events such as kicks or lost circulation. An x-ray sensor can measure the densit y of the drilling mud and its VFR, which can then be used to calculate its mass flow rate. Improved density and VFR data a llows for better control of the well bore pressure profile du ring static and circulating conditions. This improved characterizat ion of the well bore pressure profile allows one to drill well s with narrow drilling margins without non-productive time, resul ting in safer and more cost effective well construction operation s. X-ray technology shows great promise for mass flow measurements because it is based on the proven prin ciples of gamma ray densitometry, which can measure density w ith greater than 99% accuracy. Recent advances in low d ensity (~1.3 SG) and high pressure (>20 ksi) carbon reinfo rced polymers (CRPs) are making it possible to explore x ays for these measurements. These CRPs offer a lower thickn ess-topressure ratio than the high density steel (~8 SG) currently used in standpipe construction. A sensor constructed fro m CRP material would allow for significantly greater x-ra y transmission than steel, and thereby greatly reduce the voltage and power demand on the x-ray source. These lower v oltage and power demands drastically reduce the cost, size , weight and complexity of the x-ray source, making it practical and safe for use in well construction applications. Research towards developing x-ray sensor technology capable of measuring mass flow rate through a 4 inc h CRP embedded pipe with mud density and VFR not exceedin g 20 ppg (2.4 SG) and 1200 gpm respectively is presented i this paper. We begin by discussing the experiments conducted to determine the minimum x-ray source voltage and powe r required by the sensor, in order to achieve x-ray p enetration through the drilling mud (or other well constructio n fluid) and the CRP pipe. The two approaches that were explored to estimate density are then discussed. The first appr o ch is an empirical approach where sensor gray level values a r directly mapped onto mud density values determined from lab experiments. These mappings are then used in the fi eld to estimate density. The second approach is a model-ba s d approach that estimates density using the Beer Lamb erts law. The explicit assumption in developing the two densi ty methods is that the mud density is only changing due to inf lux of unwanted low gravity solids (LGS) from the formatio n. Changes from any other causes, such as temperature nd pressure variation, addition and loss of weighing m aterial, etc., require implementation of correction factors. Insta ces when these correction factors are needed are also discus sed. Preliminary results are presented from testing of a n algorithm that was developed to investigate if digi tal video of tracer particles, introduced into the circulating f luid, contains AADE-18-FTCE-126 Advanced X-ray Technology for Real-Time High Pressure Mass Flow Rate Measurement Vivek Singhal, Pradeep Ashok, and Eric van Oort, The University of Texas at Austin 2 V. Singhal, P. Ashok and E. van Oort AADE-18-FTCE-126 sufficient information to interpret fluid velocity with greater than 99% accuracy. Digital video is used for invest igation since experiments using digital images are much easier to perform than using x-ray radiographs. Upon successful testi ng of this algorithm, software will be developed that can meas ure velocity from x-ray radiographs. Results are also shared fro m an experiment designed to evaluate the capability of c ommercial imaging detectors to detect high speed tracers. X-Ray Source Power Requirements The proposed x-ray sensor consists of a steel spool piece which connects to the standpipe using a press ur tight seal. It also serves as the housing that contains t he CRP pipe and mounting provisions for the x-ray source and de tector. In this work, we will consider a polychromatic x-ray e nergy source given its lower cost, size and complexity co mpared with the monochromatic energy source. A polychromatic en ergy source generates x-rays ranging from 0 eV to the ma xi um source energy, as opposed to a monochromatic energy source which primarily generates x-rays of a single energy . The x-rays lose energy as they propagate through the pipe and the rilling mud, a process known as x-ray attenuation. For the application discussed in this paper, it is observed that the Be r Lamberts law (Eq. 1) serves as a good approximation for dete rmining the attenuation of polychromatic energy x-rays.