Proposed Practical Methods to Estimate Rock Strength and Tooth Wear While Drilling With Roller-Cone Bits

2004 ◽  
Vol 126 (4) ◽  
pp. 302-310 ◽  
Author(s):  
T. Ohno ◽  
H. Karasawa ◽  
M. Kosugi ◽  
J. C. Rowley
Keyword(s):  
Rock Strength ◽  
Penetration Rate ◽  
Tooth Wear ◽  
Rotary Speed ◽  
Two Parameters ◽  
Simple Parameter

The authors have previously developed and proposed methods to estimate the in situ rock strength and tooth wear while drilling with roller-cone bits [Karasawa et al., 2002, ASME J. Energy Resour. Technol. 124, pp. 125–132 (Pt. 1) 133–140 (Pt. 2)]. The purpose of this paper is to provide a follow-up to these two reports and to propose, for both previous methods, alternate techniques that can be more readily implemented in the field than those originally presented. The data presented in Part 1 of the previously mentioned work [1] were reanalyzed in order to find a new and simple parameter that can be used to estimate rock strength. This parameter uses only one set of data that consists of bit weight, torque, penetration rate, rotary speed, and bit diameter. It was also demonstrated that the effect of tooth wear on this new parameter is small. In addition, more practical methods, which employ two parameters, are derived and proposed to evaluate the tooth wear of roller-cone bits.

Dynamic Differential Pressure Effects on Drilling of Permeable Formations

1998 ◽  
Vol 120 (2) ◽  
pp. 118-123 ◽  
Author(s):  
L. L. Hoberock ◽  
G. J. Bratcher
Keyword(s):  
Rock Strength ◽  
Penetration Rate ◽  
Drilling Fluid ◽  
Differential Pressure ◽  
Pressure Effects ◽  
Drilling Fluids ◽  
Bottom Hole ◽  
Wellbore Pressure ◽  
Dynamic Quantity

In the mathematical modeling of bit penetration rate for tri-cone roller bits in permeable formations, virtually all of the current techniques assume that the differential pressure between the bottom-hole wellbore pressure and the formation is a “static” value. This work shows that the appropriate differential pressure is a dynamic quantity, because for overbalanced drilling, fluid filtrate from the wellbore requires a finite time to flow into the formation, producing a changing pressure gradient ahead of the bit. Moreover, this dynamic gradient is directly dependent upon the rate of drill bit penetration, which is in turn dependent upon the dynamic gradient itself. Accordingly, coupled penetration rate and dynamic gradient equations must be solved, which frequently result in the prediction of higher drilling penetration rates than when the static gradient is used. The appropriate dynamic differential pressure equations are developed and applied to an example drilling situation. It is shown that with water-based drilling fluids, for rock with permeability greater than a few microdarcies at virtually all penetration rates, and for penetration rates less than 3 m/h (9.84 ft/h) at permeabilities greater than 1 μd (microdarcy), the dynamic differential pressure is significantly less than the static differential pressure. Accordingly, using the conventional static differential pressure results in the prediction of penetration rates that are much too low. Moreover, using measured penetration rates from the field, the conventional approach yields predicted in-situ rock strength that is much too high.

Methods to Estimate the Rock Strength and Tooth Wear While Drilling With Roller-Bits—Part 1: Milled-Tooth Bits

2002 ◽  
Vol 124 (3) ◽  
pp. 125-132 ◽  
Author(s):  
H. Karasawa ◽  
T. Ohno ◽  
M. Kosugi ◽  
J. C. Rowley
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Rock Strength ◽  
Penetration Rate ◽  
Tooth Wear ◽  
Test Results ◽  
Study Methods ◽  
Hard Rocks ◽  
New Methods

This paper proposes new methods to estimate both the rock strength and tooth wear while drilling with roller-bits. Laboratory drilling tests were conducted to obtain the penetration rate, bit weight and torque using milled-tooth bits with different tooth wear (T0, T4, T7). Drilling media used for the tests were soft to medium-hard rocks whose uniaxial compressive strength ranged from 14 to 118 MPa. Based on the test results, a parameter, which presents the rock strength independent of the tooth wear, was first investigated. The investigation revealed that a parameter related to the axial energy and the rotary energy required to drill rock is effective to estimate the rock strength independent of the tooth wear. Second, methods to estimate the tooth wear were studied based on the same parameter that represents the rock strength. From the results of this study, methods to measure the tooth wear are proposed.

Outcome of Percutaneous Nephrostomy in Children With Ureteropelvic Junction Obstruction

2020 ◽  
Vol 20 (2) ◽  
pp. 61-64
Author(s):  
Mohammad Mahfuzur Rahman Chowdhury ◽  
Rifat Zaman ◽  
Md Amanur Rasul ◽  
Akm Shahadat Hossain ◽  
Shafiqul Alam Chowdhury ◽  
...  
Keyword(s):  
Renal Function ◽  
Low Dose ◽  
Ureteropelvic Junction Obstruction ◽  
Percutaneous Nephrostomy ◽  
Ureteropelvic Junction ◽  
College Hospital ◽  
Medical College ◽  
Split Renal Function

Introduction and objectives: Congenital ureteropelvic junction obstruction (UPJO) is the most common cause of hydronephrosis. Management protocols are based on the presence of symptoms and when the patient is asymptomatic the function of the affected kidney determines the line of treatment. Percutaneous nephrostomy (PCN) became a widely accepted procedure in children in the 1990s. The aim of the study was to evaluate the results of performing percutaneous nephrostomy (PCN) in all patients with UPJO and split renal function (SRF) of less than 10% in the affected kidney, because the management of such cases is still under debate. Methods:This prospective clinical trial was carried out at Dhaka Medical College Hospital from January 2014 to December 2016. Eighteen consecutive patients who underwent PCN for the treatment of unilateral UPJO were evaluated prospectively. In these children, ultrasonography was used for puncture and catheter insertion. Local anesthesia with sedation or general anesthesia was used for puncture. Pig tail catheters were employed. The PCN remained in situ for at least 4 weeks, during which patients received low-dose cephalosporin prophylaxis. Repeat renography was done after 4 weeks. When there was no significant improvement in split renal function (10% or greater) and PCN drainage (greater than 200 ml per day) then nephrectomies were performed otherwise pyeloplasties were performed. The patients were followed up after pyeloplasty with renograms at 3 months and 6 months post operatively. Results: All the patients had severe hydronephrosis during diagnosis and 14 patients with unilateral UPJO were improved after PCN drainage and underwent pyeloplasty. The rest four patients that did not show improvement in the SRF and total volume of urine output underwent nephrectomy. In the patients with unilateral UPJO who improved after PCN drainage, the SRF was increased to 26.4% ±8.6% (mean± SD) after four weeks and pyeloplasty was performed. At three and six months follow-up, SRF value was 29.2% ±8.5% and 30.8.2% ±8.8% respectively. Conclusion: Before planning of nephrectomy in poorly functioning kidneys (SRF < 10%) due to congenital UPJO, PCN drainage should be done to asses improvement of renal function. Bangladesh Journal of Urology, Vol. 20, No. 2, July 2017 p.61-64

Getting to know a new protocol in hypertension care

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Mona Lundin
Keyword(s):  
Blood Pressure ◽  
Digital Technology ◽  
Interaction Analysis ◽  
Medical Discourse ◽  
Graphical Form ◽  
Graph Data ◽  
Average Blood Pressure ◽  
Infrastructure Design

This study explores the use of a new protocol in hypertension care, in which continuous patient-generated data reported through digital technology are presented in graphical form and discussed in follow-up consultations with nurses. This protocol is part of an infrastructure design project in which patients and medical professionals are co-designers. The approach used for the study was interaction analysis, which rendered possible detailed in situ examination of local variations in how nurses relate to the protocol. The findings show three distinct engagements: (1) teasing out an average blood pressure, (2) working around the protocol and graph data and (3) delivering an analysis. It was discovered that the graphical representations structured the consultations to a great extent, and that nurses mostly referred to graphs that showed blood pressure values, which is a measurement central to the medical discourse of hypertension. However, it was also found that analysis of the data alone was not sufficient to engage patients: nurses' invisible and inclusion work through eliciting patients' narratives played an important role here. A conclusion of the study is that nurses and patients both need to be more thoroughly introduced to using protocols based on graphs for more productive consultations to be established. 

scholarly journals Intra-Cystic (In Situ) Mucoepidermoid Carcinoma: A Clinico-Pathological Study of 14 Cases

2020 ◽  
Vol 9 (4) ◽  
pp. 1157
Author(s):  
Saverio Capodiferro ◽  
Giuseppe Ingravallo ◽  
Luisa Limongelli ◽  
Mauro Mastropasqua ◽  
Angela Tempesta ◽  
...  
Keyword(s):  
Alcian Blue ◽  
Tumor Invasion ◽  
Conservative Surgery ◽  
Low Grade ◽  
Mucin Production ◽  
Cystic Component ◽  
Early Growth Phase ◽  
Hematoxylin Eosin

Aims: To report on the clinico-pathological features of a series of 14 intra-oral mucoepidermoid carcinomas showing exclusive intra-cystic growth. Materials and methods: All mucoepidermoid carcinomas diagnosed in the period 1990–2012 were retrieved; the original histological preparations were reviewed to confirm the diagnosis and from selected cases, showing exclusive intra-cystic neoplastic components, additional sections were cut at three subsequent 200 m intervals and stained with Hematoxylin–Eosin, PAS, Mucicarmine and Alcian Blue, to possibly identify tumor invasion of the adjacent tissues, which could have been overlooked in the original histological preparations. Additionally, pertinent findings collected from the clinical charts and follow-up data were analyzed. Results: We identified 14 intraoral mucoepidermoid carcinomas treated by conservative surgery and with a minimum follow up of five years. The neoplasms were located in the hard palate (nine cases), the soft palate (two), the cheek (two) and the retromolar trigone (one). In all instances, histological examination revealed the presence of a single cystic space, containing clusters of columnar, intermediate, epidermoid, clear and mucous-producing cells, the latter exhibiting distinct intra-cytoplasmic mucin production, as confirmed by PAS, Mucicarmine and Alcian Blue stains. The cysts were entirely circumscribed by fibrous connective tissue, and no solid areas or infiltrating tumor cell clusters were detected. Conservative surgical resection was performed in all cases, and no recurrences or nodal metastases were observed during follow up. Conclusions: Mucoepidermoid carcinomas showing prominent (>20%) intra-cystic proliferation currently are considered low-grade tumors. In addition, we also unveil the possibility that mucoepidermoid carcinomas, at least in their early growth phase, may display an exclusive intra-cystic component and might be considered as in situ carcinomas, unable to infiltrate adjacent tissues and metastasize.

scholarly journals Associations between Amplification (1q) and Prior Cancer in a Real-World De Novo Myeloma Cohort

2021 ◽  
Author(s):  
Elizabeth B Lamont ◽  
Andrew J Yee ◽  
Stuart L Goldberg ◽  
David S Siegel ◽  
Andrew D Norden
Keyword(s):  
Real World ◽  
Fluorescent In Situ Hybridization ◽  
De Novo ◽  
Chromosome 1 ◽  
Second Malignancies ◽  
Cancer History ◽  
Screening Strategies ◽  
Cytogenetic Testing

Abstract Genomic biomarkers inform treatment in multiple myeloma (MM) making patient clinical data a potential window into MM biology. We evaluated de novo MM patients for associations between specific MM cytogenetic patterns and prior cancer history. Analyzing a MM real-world dataset (RWD), we identified a cohort of 1,769 patients with fluorescent in-situ hybridization (FISH) cytogenetic testing at diagnosis. Fully 241 patients (0.14) had histories of prior cancer(s). Amplification of the long arm of chromosome 1 [amp(1q)] varied by prior cancer history (0.31 with prior cancer vs 0.24 without; p = .02). No other MM translocations, amplifications, or deletions were associated with prior cancers. Amp(1q) and cancer history remained strongly associated in a logistic regression adjusting for patient demographic and disease attributes. The results merit follow-up regarding carcinogenic treatment effects and screening strategies for second malignancies. Broadly the findings suggest analyses of patient-level phenotypic-genomic RWD may accelerate cancer research through hypothesis generating studies.

scholarly journals Venus: key to understanding the evolution of terrestrial planets

2021 ◽  
Author(s):  
Colin F. Wilson ◽  
Thomas Widemann ◽  
Richard Ghail
Keyword(s):  
High Temperature ◽  
High Resolution ◽  
Radar Imaging ◽  
Space Science ◽  
Interior Surface ◽  
Extended Surface ◽  
Earth Like Planets ◽  
Orbital Mission

AbstractIn this paper, originally submitted in answer to ESA’s “Voyage 2050” call to shape the agency’s space science missions in the 2035–2050 timeframe, we emphasize the importance of a Venus exploration programme for the wider goal of understanding the diversity and evolution of habitable planets. Comparing the interior, surface, and atmosphere evolution of Earth, Mars, and Venus is essential to understanding what processes determined habitability of our own planet and Earth-like planets everywhere. This is particularly true in an era where we expect thousands, and then millions, of terrestrial exoplanets to be discovered. Earth and Mars have already dedicated exploration programmes, but our understanding of Venus, particularly of its geology and its history, lags behind. Multiple exploration vehicles will be needed to characterize Venus’ richly varied interior, surface, atmosphere and magnetosphere environments. Between now and 2050 we recommend that ESA launch at least two M-class missions to Venus (in order of priority): a geophysics-focussed orbiter (the currently proposed M5 EnVision orbiter – [1] – or equivalent); and an in situ atmospheric mission (such as the M3 EVE balloon mission – [2]). An in situ and orbital mission could be combined in a single L-class mission, as was argued in responses to the call for L2/L3 themes [3–5]. After these two missions, further priorities include a surface lander demonstrating the high-temperature technologies needed for extended surface missions; and/or a further orbiter with follow-up high-resolution surface radar imaging, and atmospheric and/or ionospheric investigations.

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