scholarly journals Comparative analysis of drilling performance of kymera and PDC bits in salt formation

2020 ◽  
Vol 1 (2) ◽  
pp. 25-28
Author(s):  
Alaba O Clement

The study compares the drilling performance of Kymera and PDC bits in salt formation using River and Delta State Continental Shelf of Nigeria as a case study. The measurement while drilling (MWD) and the logging while drilling (LWD) methods were used to measure the real time well drilling operation. well formation and drilling statistics. The data obtained from the Ogbaimbiri. Ossiomo. Utorogu and Okporhuftu wells have the penetration rate of 6.2 m/hr. 5.9 m/hr. 12.2 m/hr. 6.3 m/hr for Kymera bit and 4.2 m/hr. 3.4 m/hr. 6.8 m/hr. 3.9 m/hr for PDC bit respectively. The pearson correlation coefficient has a value of r = 0.897. n = 4. p<0.05 and r = 0.784. n = 4. p<0.05 for both kymera and PDC bits. The results established a strong and positive correlation between the penetration rate and distance drilled in each bit. It also shows that the higher the penetration rate the more the distance drilled by each bit. The study concluded that the Kymera bit was more efficient as it was able to penetrate the different formations with a lesser time and at a greater penetration rate.

Author(s):  
Jeroen van Eldert ◽  
Johan Funehag ◽  
Håkan Schunnesson ◽  
David Saiang

Abstract In tunneling, rock mass grouting is a method applied to reduce water ingress. Grouting is influenced by rock mass conditions, especially apertures, frequency, and continuation of fracturing. These rock mass conditions can partly be determined by rock mass classification systems. At the Stockholm bypass, the Measurement While Drilling (MWD) Fracturing Index was applied to characterize the rock mass for grouting purposes, with a focus on adjusting the grout hole drill plan to minimize environmental impact. This study divided the rock mass in a 1.9 km tunnel into six categories based on rock mass conditions, identifying rock mass quality, apparent fracturing, and grout consumption. These categories were then compared with the mean fracturing index based on the coefficients of penetration rate and rotation pressure variations, as well as grout consumption at each grout umbrella. The fracturing index was 93% successful in assessing favorable and unfavorable rock mass conditions in the studied tunnel and 85% successful in determining grout consumption. Finally, a conceptual method was developed to reduce the grouting activities using the MWD fracturing index and water loss tests. The introduction of this conceptual method for grouting decisions could potentially reduce 59% of the umbrellas found in the case study.


2021 ◽  
Author(s):  
Raphael Chidiogo Ozioko ◽  
Humphrey Osita ◽  
Udochukwu Ohia

Abstract This paper describes the successful deployment of integrated underreamer technology with real-time communication through mud-pulse telemetry system, to drill and eliminate rathole in 17 1/2-in × 20-in successfully in one run and helped set casing as close as possible to the depth of suspected pressure ramp on an exploratory well offshore Nigeria. This technology uses the same communication system (actuator bypass) as Measurement While Drilling tools (MWD), Logging While Drilling tools (LWD) and Rotary Steerable System (RSS). Integrated underreamers broadly used in the drilling operations support optimized casing and completion programs and helps reduce operational risks such as wellbore instability. The ball drop and hydraulically activated reamer technologies available today comes with limitations and HSE risks. The distinctive functionalities of the integrated underreamer technology described here, such as unlimited and fast activation and deactivation via downlinking and real time downhole feedback, reduce uncertainties and operational costs in the complex and challenging deep offshore drilling operations. The real-time communication through mud-pulse telemetry system enabled the placement of integrated underreamer 6 meters from the bit thereby reducing rathole length to approximately 9 meters compared to 80 meters for conventional underreamer application. The integrated underreamer is compatible with existing RSS and provide unlimited activation cycles. The integrated underreamer offers flexibility in placement in the bottom hole assembly (BHA) and it can be used as a near bit reamer, or as main reamer or as both. In this case, the integrated near bit underreamer eliminated the need for a dedicated rathole removal run. It also offered a feedback confirmation of the cutter blades activation status and provided hole opening log thereby reducing the operational uncertainties for the under reaming, saving rig time up to 16 hours for shoulder test. The underreamer was successfully deployed to drill and ream the challenging 14 ¾" × 17 ½" and ream 17 ½" × 20" section offshore Nigeria. Both sections were drilled and reamed to section Total Depth (TD) in one run with all directional reuirements and Measuring While Drilling (MWD)/Logging While Drilling (LWD) met saving client approximately 4 days of rig spread cost. The reamer appeared to provide an in-gauge borehole allowing for successful running and cementing of liners without any issues, demonstrating superior borehole quality. The new Technology proved to be a reliable and flexible hole enlargement while drilling solution that help to improve drilling performance, reduce operational risks and save cost.


1992 ◽  
Vol 114 (4) ◽  
pp. 323-331 ◽  
Author(s):  
H. Karasawa ◽  
S. Misawa

Rock cutting, drilling and durability tests were conducted in order to obtain data to design polycrystalline diamond compact (PDC) bits for geothermal well drilling. Both conventional and new PDC bits with different rake angles were tested. The rock cutting tests revealed that cutting forces were minimized at −10 deg rake angle independent of rock type. In drilling and durability tests, a bit with backrake and siderake angles of −10 or −15 deg showed better performance concerning the penetration rate and the cutter strength. The new PDC bit exhibited better performance as compared to the conventional one, especially in hard rock drilling. Furthermore, a new PDC core bit (98.4 mm o. d., 66 mm i. d.) with eight cutters could be successfully applied to granite drilling equally as well as a bit with twelve cutters.


2021 ◽  
Author(s):  
Zhidong Yang ◽  
Xubin Zhao ◽  
Liang Huang ◽  
Jiasheng Deng ◽  
Wei Zhou ◽  
...  

2019 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Robert M. Anderson ◽  
Amy M. Lambert

The island marble butterfly (Euchloe ausonides insulanus), thought to be extinct throughout the 20th century until re-discovered on a single remote island in Puget Sound in 1998, has become the focus of a concerted protection effort to prevent its extinction. However, efforts to “restore” island marble habitat conflict with efforts to “restore” the prairie ecosystem where it lives, because of the butterfly’s use of a non-native “weedy” host plant. Through a case study of the island marble project, we examine the practice of ecological restoration as the enactment of particular norms that define which species are understood to belong in the place being restored. We contextualize this case study within ongoing debates over the value of “native” species, indicative of deep-seated uncertainties and anxieties about the role of human intervention to alter or manage landscapes and ecosystems, in the time commonly described as the “Anthropocene.” We interpret the question of “what plants and animals belong in a particular place?” as not a question of scientific truth, but a value-laden construct of environmental management in practice, and we argue for deeper reflexivity on the part of environmental scientists and managers about the social values that inform ecological restoration.


2013 ◽  
Vol 4 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Pernilla Liedgren ◽  
Lars Andersson

This study investigated how young teenagers, as members of a strong religious organization, dealt with the school situation and the encounter with mainstream culture taking place at school during the final years in Swedish primary school (age 13–15 years). The purpose was to explore possible strategies that members of a minority group, in this case the Jehovah’s Witnesses, developed in order to deal with a value system differing from that of the group. We interviewed eleven former members of the Jehovah’s Witnesses about their final years in compulsory Swedish communal school. The ages of the interviewees ranged between 24 and 46 years, and the interviewed group comprised six men and five women. Nine of the eleven interviewees had grown up in the countryside or in villages. All but two were ethnic Swedes. The time that had passed since leaving the movement ranged from quite recently to 20 years ago. The results revealed three strategies; Standing up for Your Beliefs, Escaping, and Living in Two Worlds. The first two strategies are based on a One-World View, and the third strategy, Living in Two Worlds, implies a Two-World View, accepting to a certain extent both the Jehovah’s Witnesses outlook as well as that of ordinary society. The strategy Standing up for Your Beliefs can be described as straightforward, outspoken, and bold; the youngsters did not show any doubts about their belief. The second subgroup showed an unshakeable faith, but suffered psychological stress since their intentions to live according to their belief led to insecurity in terms of how to behave, and also left them quite isolated. These people reported more absence from school. The youngsters using the strategy Living in Two Worlds appeared to possess the ability to sympathize with both world views, and were more adaptable in different situations.


Author(s):  
Y. D. Mulia

For S-15 and S-14 wells at South S Field, drilling of the 12-1/4” hole section became the longest tangent hole section interval of both wells. There were several challenges identified where hole problems can occur. The hole problems often occur in the unconsolidated sand layers and porous limestone formation sections of the hole during tripping in/out operations. Most of the hole problems are closely related to the design of the Bottom Hole Assembly (BHA). In many instances, hole problems resulted in significant additional drilling time. As an effort to resolve this issue, a new BHA setup was then designed to enhance the BHA drilling performance and eventually eliminate hole problems while drilling. The basic idea of the enhanced BHA is to provide more annulus clearance and limber BHA. The purpose is to reduce the Equivalent Circulating Density (ECD,) less contact area with formation, and reduce packoff risk while drilling through an unconsolidated section of the rocks. Engineering simulations were conducted to ensure that the enhanced BHA were able to deliver a good drilling performance. As a results, improved drilling performance can be seen on S-14 well which applied the enhanced BHA design. The enhanced BHA was able to drill the 12-1/4” tangent hole section to total depth (TD) with certain drilling parameter. Hole problems were no longer an issue during tripping out/in operation. This improvement led to significant rig time and cost savings of intermediate hole section drilling compared to S-15 well. The new enhanced BHA design has become one of the company’s benchmarks for drilling directional wells in South S Field.


2019 ◽  
Vol 18 (2) ◽  
pp. 99-114
Author(s):  
M. Chebaibi ◽  
D. Bousta ◽  
I. Iken ◽  
H. Hoummani ◽  
A. Ech-Choayeby ◽  
...  

The purpose of this study was to inventory and collect information on plants and mixtures commonly used by herbalists to treat kidney disease in the Fez–Meknes region. We also aimed to compare the results obtained with the results of the other studies and exploit the correlations between different factors. An ethnopharmacological survey was conducted from 289 local herbalists in eight different areas of Fez–Meknes region. Ethnomedicinal uses and ethnobotanical indices were analyzed using quantitative tools, i.e., the total number of citation (TNC), use value (UV), family use value (FUV), fidelity level (FL), and rank order priority (ROP). Statistical analyses such as Pearson correlation and chi-squared test were performed to delineate any correlation. Two hundred and eighty-nine herbalists were questioned. Sixty-nine plant species belonging to 38 families were cited by herbalists for traditional treatment of kidney disease. The highest value of UV was obtained for Herniaria glabra L. (UV = 0.79), and Caryophyllaceae was the family frequently cited (FUV = 0.795). Ammodaucus leucotrichus Coss. & Dur. had the highest value of FL with a value of 100%, and the highest value of ROP was recorded for Herniaria glabra L. (ROP = 91%). Sociodemographic characteristics had a significant impact on the knowledge of toxic plants. Our study has revealed a cultural heritage linked to herbalism and a great wealth of medicinal plants, whose valorization and protection are necessary. Several studies are needed to sensitize herbalists and population on the danger of toxic plants, to extract chemical compounds from the main plants used, and to evaluate their toxicity.


2020 ◽  
Vol 1 (1) ◽  
pp. 108-125
Author(s):  
Jaharuddin Jahar ◽  
Melia Rostiana ◽  
R Melda Maesarach

The purpose of this study was to decide the elements of performance at PT. General Takaful Insurance, to find out how to measure performance using the scorecard approach that is by measuring process performance and results performance, and interpreting in the form of conclusions. In this study, researchers tested apply maslahah at PT. General Takaful Insurance with a case study design. This research is a type of quantitative and qualitative research because it uses measurement data through formulas and if interpretative qualitative, and the data used are primary and secondary data. Data collection methods used are observation, interviews and documentation. The results showed that PT. General Takaful Insurance received a value of the performance benefit process of 0.7 which indicates that the company simply applied benefits in terms of process performance. And behave the benefit of PT. General Takaful Insurance got a value of 0.89 which shows that the company is quite good in providing benefits to stakeholders and shareholders. Keyword: Performance, Insurance, Scorecard Maslahah


2017 ◽  
Vol 4 (9) ◽  
pp. 1700132 ◽  
Author(s):  
Adam A. L. Michalchuk ◽  
Ivan A. Tumanov ◽  
Sumit Konar ◽  
Simon A. J. Kimber ◽  
Colin R. Pulham ◽  
...  

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