Development of Whirl Resistant PDC Bits

In order to study the rock breaking efficiency of the annular-grooved PDC bit, a test bit with adjustable diameter of 241.3 mm was designed and manufactured. The test bit was used for bench test with adjustable parameters such as width, height, number and radial position of annular groove in two rock samples of sandstone and granite. The results show that compared with conventional PDC bit, the rock-breaking mechanical specific energy (MSE) of the annular-grooved PDC bit is reduced by 33%, and the more the number of the annular groove is, the smaller the rock-breaking mechanical specific energy is and the faster the mechanical bit is; The annular groove is disposed outside and in the core of the bit. The smaller the rock-breaking mechanical specific energy of the bit is, the faster the mechanical drilling speed is; In the sandstone and granite samples, there is an optimal annular groove size (height and width), and the bit’s mechanical drilling speed has been increased. Among them, the speed increase is the most obvious in the sandstone, and the mechanical bit is increased by 27% to 160%. The rock mechanical specific energy is reduced, indicating that annular-grooved PDC bit is suitable for both soft and hard lithology, and has a speed-up effect on both types of strata.

Drilling the deep lithology column using PDC bits in the Obayied field of Egypt's Western Desert has been extremely difficult. The field's lithology column represents an amplification of all of the typical lithology characteristics in the Western Desert. The highly interbedded sandstone, siltstone, and shale—along with the variance of such interbedding across the field—has been a significant challenge for well planners and has adversely affected cost per foot. The application is characterized as predominantly abrasive and impact-intensive in the same section, hence challenging for PDC bit durability. To efficiently drill the 8½-in interval, a fundamental change in PDC bit design is required. Considering these formidable challenges, service providers had to evolve PDC bits to meet the constant demand of improving performance and reducing costs. Focus was concentrated on balancing new technology developments and the willingness to invest on field trials. To accomplish these objectives in the Obayied field, the operator and the service provider identified two main problems—developing an in-depth understanding of rock strength characteristics of each individual formation in the deep rock column and its variance across the field, and developing PDC bits that can survive such a challenging rock column with improved durability and ROP. Recently, a novel conical diamond element (CDE) with extreme impact- and abrasion-resistant characteristics has been developed. The CDE has been incorporated at bit center in a new and innovative PDC design, solving the traditional challenge of the inefficient characteristic of PDC bit central area. In addition, a field-wide rock strength study based on sonic and gamma rays logs provided the transparency required for better planning and risk management to resolve the operational inefficiencies traditionally seen in the Obayied field. The new PDC bits utilizing the CDE technology has been deployed in Obayied and has reduced consumption to just 3–4 bits per section in 2014, whereas that number was 8–10 bits per section averaged in 2006. The new bit has also reduced the average number of days to drill the section from as low as 6 days to reach TD instead of 20 days. Performance gains were achieved both in ROP and footage totals in the most challenging formations, including Alam Al Buwaib, Upper Safa, and Lower Safa. The authors will discuss the benefits of this industry collaboration that achieved exceptional performance improvement leading to dramatic cost savings in the Obayied field.

Deuxieme partie de l'etude de conception d'un outil diamant equipe d'un compact a diamant polycristallin (PDC): presentation des algorithmes utilises par le logiciel PDCWEAR (FORTRAN 77). PDCWEAR analyse les performances et l'usure de ce type d'outil diamant en cours de forage. Un cas concret est analyse a l'aide de PDCWEAR, des conclusions en sont tirees quant aux effets de profil de l'outil, du nombre de dents, de la vitesse de rotation, de l'assistance d'un jet d'eau et du mode d'usure des dents

Well A is a geothermal well in K field, located in the Jambi area of Sumatera. The pilot hole of the 17.5-in section was drilled to total depth (TD). However, a 13.375-in casing running difficulty was experienced afterwards. A dedicated cleanout bottomhole assembly (BHA) was run, but this became stuck. The decision was taken to plug the pilot hole with a cement plug and to perform an openhole sidetrack. The difficulty in running the 13.375-in casing is caused by collapsing formation from the borehole wall. The commonly run casing/liner tieback system has no rotational capability when an obstruction is encountered while running the casing. The 13.375-in × 17.5-in nondirectional casing drilling technology was proposed as the solution. The main component of this technology is the drillable alloy casing bit, which drills on standard casing that is rotated at the surface. The casing bit is equipped with PDC cutters and nozzles with the same function as those in a conventional PDC bit. The casing can be fully rotated while applying weight to cut through the obstruction. The casing drilling system successfully set the 13.375-in casing to 849.72-m measured depth (MD), 314 m deeper than the initial point of the casing running obstruction. The drilling/reaming capability of the casing bit helped in cutting all the formation filling the predrilled hole. The cementing process was executed well, with good integrity to the surface, shown not only by a surface return during the cement top job but also by a good cement bond log (CBL) result. This eliminated the requirement of having a casing/liner tieback system, which saved operating time and cost. The ability to set the casing deeper enabled sealing off the total loss zone. Consequently, the 12.25-in section drilling could be executed without penetrating the problematic zone, which improved drilling efficiency.

Developing reserves in Kazakhstan's Chinarevskoe field frequently requires the operator to drill an 8.5-in. vertical hole section through extremely hard carbonates which contain high concentrations of problematic chert inclusions. The first significant chert layer is encountered at 3050-3110m, which has 10-50% chert content. Penetrating the chert interval with PDC bits has been challenging and in many cases impossible due to the cutters' inability to withstand high impact forces, which resulted in catastrophic cutter damage. The application of impregnated bits on high-speed turbines (1300-1400 RPM) led to significant improvement in run lengths and this BHA became the standard approach.1 One impregnated bit could drill approximately 550m at 3.4m/hr. The hole section typically requires three bits to reach TD. However, the impregnated bit generated very small cuttings and high frictional heat altered chip appearance hampering lithology characterization and efforts to identify formation properties. Additionally, the centrifuge was unable to separate the extremely small cuttings from the drilling fluid, resulting in a gradual increase in mud weight over the interval creating the need for constant mud replacement. Tests with PDC were once again attempted, but when the bit encountered a high percentage chert interval, the bits were damaged and pulled in poor dull condition (7-6-CR). After repeated attempts with PDC, the operator realized wellbore verticality was compromised, which required correction run with impreg/turbine BHA with not optimum parameters leading to extra drilling time. The drilling team conceded the chert layers could not be drilled with a conventional PDC/motor BHA. The operator required PDC bit that could efficiently drill long intervals of carbonate formation at high ROP with a durable cutting structure that would remain intact when encountering the chert intervals. To develop a durable bit solution, engineers used an FEA-based modeling system to implement an innovative hybrid-type bit by strategically positioning multiple conical diamond elements (CDE) and conventional PDC cutters across the entire cutting structure from bit center to gauge. This new-style cutting structure leverages the CDE's aggressive shape and superior impact and wear resistance to create a high-efficiency plowing/shearing action that improves performance in difficult formations. The analysis indicated the new hybrid bit would improve performance and be capable of surviving shock and vibration while drilling the hard carbonate/chert formations. The CDE bit was field tested on rotary steerable BHA and drilled 615m at an ROP of 9.1m/hr through the carbonate formation that contained 10-40% chert inclusions throughout the entire interval. Compared to offsets drilled with an impreg/turbine BHA, the CDE bit drilled 12% more meters at 166% higher ROP while providing good wellbore quality and came out with excellent dull condition (1-1-CT). The bit generated much larger cuttings enabling wellsite geologists to readily identify lithology type and properties. The larger drilled cuttings were easily separated by the centrifuge saving the operator $63,000USD in mud replacement costs. The high ROP of the CDE bit saved the operator six-days of rig time reducing cost/meter by 26% for a total savings of $192,000USD.

Study of rock-breaking performance of V-axe-shaped PDC cutter in tight sandstone formation

Drilling the 12¼-in hole in southern Kuwait usually starts in a shale formation and continues through interbedded sandstone, limestone, and shale. The unconfined compressive strengths throughout the section vary from 6,000 psi to 10,000 psi. The bit types typically used in this section are six-bladed PDC bits with either 16-mm or 19-mm cutters. Because fields in the area are development fields, the main objective for the operator is to achieve the best rate of penetration (ROP) and complete the section as quickly as possible. A common objective was decided on between the operator and bit provider to design a bit to drill the 12¼-in section in one run with ROP above the current benchmark. Different design configurations with different blade counts, cutter sizes, and cutting structures were analyzed using dynamic simulation based on finite-element analysis (FEA). The simulations were run in a dynamic environment to arrive at a design suitable to drill the application. The cutters were designed to withstand excessive wear, enabling the cutters to stay sharper for a longer interval and drill faster relative to previously used bits until the end of the run. Once the suitable bit was designed, different parameters were run in the simulation to define a set of parameters to be applied while drilling the actual well. The offset wells had delivered ROP in the range of 83–93 ft/h. The new design drilled the entire section in one run in 8.7 hours, attaining an ROP of 108.6 ft/h. This represents an ROP improvement of 18% over the benchmark ROP, setting a new benchmark ROP for this application. A combination of changing the bit configuration and cutter type along with the optimized cutting structure enabled the bit to last longer and drill faster than previous bits, saving the operator the cost for the associated drilling hours.

Cutting and friction forces have been widely studied for PDC bits. Rock/bit interaction models are currently verified with a single cutter experiment and the utilization of multi-axis load cells. This paper aims to demonstrate an innovative method that experimentally validates the embedded cutter sensing on a laboratory scaled-drill bit to measure the forces acting on a single cutter. A unique two-cutter drill bit design allows the integration of a sensor measuring the applied force on a cutter while drilling. A fully instrumented mini-rig is a key criterion to recreate the drilling environment. Control of the system and data analysis are performed while drilling, allowing continuous assessment of the drilled formations. Experiments are performed with new and worn cutters to independently evaluate the cutting and frictional components of the total measured force and compare them to the literature models. The high-frequency measurements at the cutter downscale the understanding that industry has on the bit-rock interaction and bring it to the cutter scale. The effective cutting area changes dynamically depending on the position of the cutters in three dimensions and axial speed. The architecture of the mini-rig control system allows accurate control of depth of cut and interactive graphs of the acquired data. The cutter sensing enables spatial monitoring distribution of the cutting forces over the face of the scaled-drill bit. Cutter/rock interaction models are validated with the acquired data from the cutter force sensing, enabling the evaluation of drilling efficiency while drilling different layers of rocks. Each cutter contributes to the weight-on-bit and torque-on-bit; thus, force sensing on a single cutter allows comprehensive performance evaluation for known drill bit design. The study of new and worn cutters provides insightful information on the drilling process in the cutter scale. In perspective, cutter force sensing might enable monitoring the wear evolution of individual cutters, which is impossible to detect with existing at-the-bit sensors. The present work assesses the potential of integrating a force sensor at the cutter. The development of this work built the foundation for up-scaling research on cutter force monitoring.

Worldwide energy infrastructures are shifting to renewable, but intermittent sources, requiring new solutions for energy storage and conversion. Solid oxide fuel cells are attractive for their high energetic efficiencies, but poor performance in oxygen electrodes contributes to high material costs preventing their widespread adoption. Improving the performance of these technologies is often hindered by inadequate knowledge of localized kinetic and transport behavior. Spatial averaging across the electrode structure makes these properties inaccessible to typical bulk electrochemical characterization techniques like DC polarization and AC impedance spectroscopy. Conversely, chemically sensitive operando and in situ techniques spatially resolve local behavior but struggle to separate physics by timescale. We aim to bridge this gap by extending on previous work using synchrotron-based operando micro X-ray absorption spectroscopy (µ-XAS)1–3 with steady periodic voltage perturbations to isolate and spatiotemporally resolve physics.We introduce this technique – called frequency-resolved X-ray absorption spectroscopy (fr-XAS)– by showing one-dimensional oxygen vacancy distribution images in a patterned thin film La0.6Sr0.4CoO3-δ electrode. Oxygen vacancies in the electrode are compensated by Co oxidation state, resulting in Co K-edge absorption shifts. At a fixed incident X-ray energy, the edge shifts appear as vertical changes, providing a direct measure of electrode oxidation state in the irradiated volume. Scanning the X-ray beam across the electrode and measuring the absorption shift at each point over time (with Fourier analysis to accurately distinguish shifts caused by the voltage perturbation from noise in the signal) allows us to construct the oxygen vacancy distribution images. The oxygen chemical potential is equilibrated at the electrode/electrolyte interface controlled by the voltage with gradients extending away from the interface determined by surface exchange and ionic transport processes. Changing the perturbation frequency separates observed physics by timescale and allows for directly extracting kinetic and transport parameters.Initial results show good quantitative agreement with a one-dimensional Gerischer model, and extracted vacancy diffusion coefficients and surface exchange rates are within a factor of 10 from literature values on porous electrodes.4,5 Impedance results from the same sample are obfuscated by extraneous processes past the point of reasonable interpretation, thereby highlighting the power of fr-XAS to extract meaningful parameters despite extraneous factors. These promising results demonstrate proof-of-concept for fr-XAS and provide motivation for the community to adapt this framework for other material systems relevant to energy storage and conversion technologies.(1) Fujimaki, Y.; Watanabe, H.; Terada, Y.; Nakamura, T.; Yashiro, K.; Hashimoto, S.; Kawada, T.; Amezawa, K. Direct Evaluation of Oxygen Chemical Potential Distribution in an SOFC Cathode by In Situ X-Ray Absorption Spectroscopy. ECS Trans. 2013, 57 (1), 1925–1932. https://doi.org/10.1149/05701.1925ecst.(2) Amezawa, K.; Fujimaki, Y.; Nakamura, T.; Bagarinao, K. D.-; Yamaji, K.; Nitta, K.; Terada, Y.; Iguchi, F.; Yashiro, K.; Yugami, H.; Kawada, T. (Invited) Determination of Effective Reaction Area in a Mixed-Conducting SOFC Cathode. ECS Trans. 2015, 66 (2), 129–135. https://doi.org/10.1149/06602.0129ecst.(3) Amezawa, K.; Fujimaki, Y.; Mizuno, K.; Kimura, Y.; Nakamura, T.; Nitta, K.; Terada, Y.; Iguchi, F.; Yugami, H.; Yashiro, K.; Kawada, T. (Invited) Triple Phase Boundary Reaction in a Mixed-Conducting SOFC Cathode. ECS Trans. 2017, 77 (10), 41–47. https://doi.org/10.1149/07710.0041ecst.(4) Lu, Y.; Kreller, C.; Adler, S. B. Measurement and Modeling of the Impedance Characteristics of Porous La1 − x Sr x CoO3 − δ Electrodes. J. Electrochem. Soc. 2009, 156 (4), B513–B525. https://doi.org/10.1149/1.3079337.(5) Søgaard, M.; Hendriksen, P. V.; Mogensen, M.; Poulsen, F. W.; Skou, E. Oxygen Nonstoichiometry and Transport Properties of Strontium Substituted Lanthanum Cobaltite. Solid State Ionics 2006, 177 (37), 3285–3296. https://doi.org/10.1016/j.ssi.2006.09.005.

Supersonic separator is investigated via process simulation for treating CO2 rich (>40%) natural gas in terms of dew-points adjustment and CO2 removal for enhanced oil recovery. These applications are compared in terms of technical and energetic performances with conventional technologies, also comparing CO2 emissions by power generation. The context is that of an offshore platform to treat raw gas with 45%mol of CO2, producing a lean gas stream with maximum CO2 composition of ≈20%mol, suitable for use as fuel gas, and a CO2 rich stream that is compressed and injected to the oil and gas fields. The conventional process comprises dehydration by chemical absorption in TEG, Joule-Thomson expansion for C3+ removal, and membrane permeation for CO2 capture. The other alternatives use supersonic separation for dew-points adjustment, and membranes or another supersonic separation unit for CO2 capture. Simulations are carried out in HYSYS 8.8, where membranes and supersonic separation are modeled via unit operation extensions developed in a previous work: MP-UOE and SS-UOE. A full technical and power consumption analysis is performed for comparison of the three cases. The results show that the replacement of conventional dehydration technology by supersonic separators decreases power demand by 8.5%, consequently reducing 69.66 t/d of CO2 emitted to the atmosphere. The use of supersonic separation for CO2 capture is also superior than membranes, mainly due to the production of a high-pressure CO2 stream, that requires much less power for injection compression than the low-pressure permeate stream from membranes. Therefore, the case with two supersonic separator units in series presents the best results: lowest power demand (-23.9% than conventional case), directly impacting on CO2 emissions, which are reduced by 2598 t/d (-27.82%).

Vibrations 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. Downhole measurement of vibrations, however, can provide valuable information about downhole conditions and characteristics of the formations drilled. Uniaxial compressive strength is one of the representative characteristics of rock properties. It shows the capacity of a rock to withstand a certain amount of axial loads. Optimizing weight on bit and rotary speed of the drill string are the ways to continue drilling a hole - of course by exceeding uniaxial compressive strength of formations - and to keep rate of penetration in an optimal range during drilling operations. Therefore, it is expected that the axial vibrations change with variations of the uniaxial compressive strength of formations. Previous experiments with several layered concretes cubes proved that the drill string vibrations are related to the uniaxial compressive strength of concretes. To extend the study in this area, complex rock samples such as sandstone, dolomite and limestone were drilled with optimized ranges of weight on bit and rotary speed of drill string. Experimental drilling operations were conducted using a laboratory drilling rig (CDC miniRig) with a vibration sensor sub attached to the drill string. The uniaxial compressive strength of all samples was measured prior to the experiments. During all experiments, drilling parameters were recorded with a sampling rate of one second and the vibration data with a sampling frequency of 3200 Hz. Analysis of magnitude and higher order frequency moments of vibration data in combination with the mechanical specific energy demonstrated a change of the drill string's axial vibration measurements due to variations of uniaxial compressive strength. From that it is concluded that the formations can be recognized in real-time by incorporation of the vibration measurements. Introduction When talking about drill string vibrations, in most of the time downhole fatigue failure, severe bit wear and reduced rate of penetration come to the mind. Drill string vibrations are inevitable in the drilling operations and lots of researches have been investigated to manage the magnitude of vibrations by designing proper bottom hole assemblies (Macpherson et al., 1993; Chen et al., 2006). However, the vibrations can be utilized as a valuable tool to recognize formations drilled. In most of the cases, the vibrations are caused by bit and drill string interaction with the formations under certain drilling conditions. One of the dominant conditions is formation characteristics (mechanical and petrophysical properties). Uniaxial compressive strength (UCS) is one of the representative characteristic of the formation properties. It shows the capacity of a formation to withstand a certain amount of axial loads. Previous works show that the harder the formation, the bigger the magnitude of the vibrations and vice versa (Esmaeili et. al, 2012). Therefore monitoring vibrations in real-time can advance warning of formation changes. Myers et al. (2002) explained how the vibration data measured by an accelerometer are related to petrophysical properties of the formations in the Indian Ocean region. Al-Shuker et. al. (2011) presented changes in drilling dynamics driven by the bit's interaction with the formation can be a near instantaneous indicator of changes in formation characteristics. The key is real-time drilling dynamic measurement at the bit. Previous works (Esmaeili et al., 2012) presented a close relationship between the mechanical properties of layered concretes cubes and the measured vibrations. The study proved that the vibrations can be used as a tool to recognize the formation changes.

291 Background: Positron emission tomography (PET) is an imaging technique whose principle is the detection of metabolic activity of tumor cells but in urology its use had been restricted due to urinary excretion of the radiotracer and overlap with urological structures, the use of hybrid PET (PET-CT) would allow its use for monitoring patients with urothelial tumors. Methods: Between 2007 and 2010 we performed PET-TC images in consecutive patients with suspected recurrences in CT scan or MRI. All patients had renal, bladder and uretral cancer and were treated with urothelial cancer diagnosis. We evaluate the usefulness of FDG PET-CT and its impact on behavior therapy in suspected recurrence in patients with urothelial carcinoma, compared with conventional studies. Results: 17 patients were studied for suspected recurrence. All patients had positive images previously on CT scan and MRI; positive PET-TC was observed in 14 and 3 studies were negative. The positive PET-CT showed more number of lesions and change the medical and surgical strategy. Of the three studies negative on PET- CT none had recurrence and remain disease free. PET/CT is in a great benefit to the detection recurrence in the follow up of patients with urothelial cancer diagnosis. These results showed an increased sensitivity and specificity over previous work with conventional PET technology. In the series studied, the implementation of PET-CT (FDG) in the follow up of patients with urothelial tumors were an useful tool. Conclusions: PET/CT is in a great benefit to the detection recurrence in the follow up of patients with urothelial cancer diagnosis. These results showed an increased sensitivity and specificity over previous work with conventional PET technology. In the series studied, the implementation of PET-CT (FDG) in the follow up of patients with urothelial tumors were an useful tool. However, multicenter studies and more patients are required to define its role. No significant financial relationships to disclose.

This paper presents an algorithm for estimating the interaction forces between model objects contacting at multiple points. The authors' previous work addressed the interaction forces that arise between two convex polyhedra, and the development of an efficient algorithm for detecting the interaction and for estimating the interaction forces. To deal with the general case of multiple contacts, the authors consider the non-convex objects as a set of convex polyhedral parts. The problem of calculating the interaction forces with multiple contacts can be divided into multiple problems involving the calculation of the interaction forces arising between two convex objects making a single contact. By implementing this algorithm on a parallel processing system, the authors constructed a real-time operating simulator. Preliminary experiments, involving the placement of a cube in a corner, were performed to evaluate the effectiveness of the system. >

Although most often associated with high-pressure production, a reliable system enabling subsea wells to be produced safety at long tie-back distances through flowlines rated to less than shut-in wellhead pressure offices cost savings for many developments. Previous work has shown that there is a sma/1 but finite probability of conventional flow control systems failing to shut off damaging overpressures. In most cases, this will arise from mechanical problems which are more likely causes than electronic failure within the production control system. The proposed system provides a viable means of implementing a pressure specification break through the use of a modular, configurable system comprising four main components. T4e system is semi-autonomous, with dedicated pressure sensors and high integrity electronics being incorporated to avoid common mode system failures. Routine telemetry and reset capability would be conductedthrough the electro-hydraulic production control system. The near-term availability of this protection system is an important consideration in justifying the economic viability of many marginal field developments. 1. Introduction The capability to produce into pipelines rated for less than full wellhead shut-in pressure can lead tosubstantial savings in pipeline materials and installation costs, The most obvious savings may be made in high pressure systems where a combination of pressure and fluid properties demand very heavy wall pipe or duplex stainless material too thick to be welded with current technology, A less prominent but more common situation is lower pressure developments where reservoir pressures drop rapidly after a brief period of production but lines are designed for initial start-up conditions. The high integrity overpressure protection system (HIOPS)is an important concept in facilitating this solution. This paper builds on some of the earliertheoretical work conducted by proposing a modular hardware solution using available technology, flexible enough to meet the requirements of current field scenarios, It should be stressed that this approach isput forward as one possible solution only, other methods may be appropriate according to specificfunctional requirements. Refs 1,2. The configuration of the protection system is a complex problem. The wide variety of production scenarios, offsets, and fluid characteristics, means that differing requirements will be posed by many developments and the most cost effective system solution will at times consist of different elements of the complete system descibed in this paper, The main characteristics which distinguish potential IOPS applications areHigh wellhead shut-in pressure, typically >5,000 psiExtended tie back to host Platform/facilities >25Km These two characteristics have a significant impact on the economic viability of a proposed development using conventional pipeline technology. Under normal operating conditions the subsea production control system provides the necessary protection in the event of failure as a result of pressure build-up. Single valve failures will seldom lead to serious consequences. Most serious problems, however, are ascribed to mechanical rather than electronic components, These have involved crimped umbilicals, contaminated control luids, valves packed with hydrates or sand, orpressure transducers rendered inoperative by accumulations of paraffin or hydrates.

Secure free-space data links can be established using conventional laser communication technology or, if necessary, they can be further enhanced with quantum encryption. Security features of these systems are based on the protocols that make use of the inherent properties of laser light. In this case, encryption does not rely on complex mathematical algorithms that add overhead to the communication stream, but instead it is based on physical-layer processes in the laser sources and other modulating components. One promising approach is based on polarization entanglement between correlated photon pairs to achieve data encryption in quantum communication systems. The foundation of security lies in the response of photons to polarization measurements. Additional degrees of freedom can be added to each “singleparticle” state by using hyper-entanglement. The situation can be visualized when several carrier waves are assigned specific frequencies in the 100 GHz International Telecommunication Union (ITU) grid. The two technologies that can be eventually integrated to achieve this task include hyperspectral quantum circuits and the entangled pair source and detection systems. This results in frequency/polarization hyper-entanglement, which can be processed with additional wavelength-division multiplexing (WDM) components to achieve efficient separation of the signals. It is important to understand that most of the previous work is theoretical and assumes ideal properties of all optical parts. In reality, many non-ideal features of the quantum circuits and their components can change the way the quantum states are processed, and this constitutes the main focus of our paper.