Developing a drilling fluid compensator for increasing the technological condition of drilling equipment

The aim of this project is to remove or eliminate the effect of the highly toxic gas of H2S on the health of personal, environment, drilling fluid reology, and drilling equipment materials by adding an economic mixture of sulphide scavengers to the contaminated drilling fluid. In this research mixture of 14.7 gm/l of iron oxide in the form of magnetite (Fe3O4) and 14.7 gm/l of ferrous oxalate Fe(C2O4), which cost is 1.3 US$ per 1kg of mixture, was used to remove the all forms of soluble sulphides (H2S, HS-, S2-) from water-base drilling fluid. The Fe3O4 reacts with dissolved H2S and the reaction carry on fast at pH below 8, while Fe(C2O4) reacts with HS-, S2- and this reaction proceed at high rate at pH above 8. Both reactions produce insoluble iron sulphides. The chemical analysis showed that the soluble species of sulphides in the drilling fluid, which its pH was 7.9, were present as dissolved H2S gas and as bisulphide ions (HS-). The analysis also explained that the total concentration of these sulphides in the drilling fluid was 3000 ppm. The results of treatment of contaminated fluid showed that all forms of sulphides were removed from drilling fluid after adding the mixture of scavengers to the contaminated fluid. The results also explained that the drilling fluid reology recovered after removing the soluble sulphides, which were the main factors that effect on the drilling fluid reology, from the drilling fluid.

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Fatigue Evaluation of Drill Pipes for Scientific Drilling Program by Applying Non-Stop Driller Concept

Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology ◽

10.1115/omae2019-95896 ◽

2019 ◽

Cited By ~ 1

Author(s):

Tomoya Inoue ◽

Masahiko Fujikubo ◽

Kenji Nakano ◽

Noriaki Sakurai

Keyword(s):

Time Series ◽

Fatigue Strength ◽

Nankai Trough ◽

Drilling Fluid ◽

Drill Pipe ◽

Ship Motions ◽

Bending Stress ◽

Deep Drilling ◽

Scientific Drilling ◽

Drilling Equipment

Abstract The scientific drilling vessel Chikyu is performing Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE), a challenging deep drilling activity, for scientific purpose. We faced difficulty to drill deep during past NanTroSEIZE operations due to unstable sediments and insufficient cutting removal. Non-Stop Driller concept is, therefore, applied for the operation of NanTroSEIZE scheduled to start Oct. 2018 to enable continuous circulation of drilling fluid circulation. The Non-Stop Driller concept requires an additional, specially-designed sub called an “NSD sub” with a ball valve for drilling fluid inlet. Generally, the fatigue strength of a drill pipe is a critical factor governing the performance of challenging deep drilling. This study, therefore, focused on the fatigue failure of the NSD sub due to the bending stress caused by interference with risers including flex joints, ship structure, or drilling equipment resulting from ship motions. The bending stress leads to cyclic stress caused by rotation of the drill pipe. This is especially the case at the Nankai Trough where ocean currents are very strong reaching or sometimes exceeding 4 knots, a high bending stress is assumed to be exerted on the NSD sub. Full-scale fatigue tests of the NSD sub were first conducted to acquire the actual fatigue curve. Further, the bending stress distribution of a drill pipe, which refers to the locus of the bending stress during the drilling operation, was analyzed by considering interference of the drill string with the structure, drilling equipment, and risers that are deformed by the ocean current. Time-series ship motions is prepared using the response amplitude operators of the Chikyu for the sea states at Nankai Trough area, and then time-series stress response is obtained by considering the operational conditions such as rate of penetration and rotational velocity of drill pipe. The numbers of occurrence of each stress amplitude can be counted from the time-series stress response. Consequently, the cumulative damage ratio is calculated for evaluating the fatigue of the NSD sub. The results confirmed that the cumulative fatigue is within a safe range. This study focused on the evaluation of the fatigue strength of the specially designed NSD sub for the challenging scientific drilling operation at Nankai Trough, a harsh environment because of the presence of strong ocean currents. This paper presents the overview of NanTroSEIZE including the Non-Stop Driller concept, and the results of fatigue evaluations.

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Application and Cognition of Unconventional Horizontal Well Drilling Technology in Shengli Oilfield

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.318.513 ◽

2013 ◽

Vol 318 ◽

pp. 513-518

Author(s):

Hong Bo Niu ◽

Hong Shan Zhao ◽

Ji Fei Cao

Keyword(s):

Drilling Fluid ◽

Gas Field ◽

Horizontal Section ◽

Well Drilling ◽

Drilling Equipment ◽

Shengli Oilfield ◽

Well Design ◽

Drilling Technology ◽

Catenary Curve ◽

Oil Gas

Long Horizontal Section Well has been an important way to explore deficient oil/gas field. Relative drilling technology has developed rapidly in recent years in China. This article puts focus on the methodology of well plan, trajectory control and matched tools and application situation of drilling fluid and drilling equipment for long horizontal section well. Based on the analysis of drilling and completion technical difficulties, suitability of some well design methods such as catenary curve used to decline friction and torque have been discussed, and even more practical means proven in many designs have been recommended. After introducing the drilling capability of the long horizontal-section well, the article indicated some special characteristic of the horizontal section wells and difference from ERD wells. Consequently, some advice is given on the definition and development of the drilling technology of long horizontal section wells.

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Flow Field Analysis on the Erosion Prone Parts of the Drilling Equipment

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.697.350 ◽

2014 ◽

Vol 697 ◽

pp. 350-355

Author(s):

Qing Lei Wang ◽

Li Ping Dong

Keyword(s):

Flow Field ◽

Theoretical Basis ◽

Drilling Fluid ◽

Rate Of Change ◽

Field Analysis ◽

Fluid Flow Rate ◽

The Finite Element Method ◽

Drilling Equipment ◽

Flow Field Analysis ◽

Drilling System

The erosion and wear mechanism for drilling equipment is studied in this paper, which is for the problem of unstable performance of drilling system and short lifetime caused by the erosion of drilling equipment by drilling fluid. The flow field, surface pressure of the erosion prone parts and drilling fluid flow rate are calculated by the finite element method. The results demonstrate the parts eroded seriously by drilling fluid appear in where the curvature of the curve of the wall changes suddenly and where the rate of change in the stress field is greater, which provide a theoretical basis on design, optimize, repair of drilling equipment.

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New technique for access-borehole drilling in shelf glaciers using lightweight drills

Journal of Glaciology ◽

10.3189/2014jog13j211 ◽

2014 ◽

Vol 60 (223) ◽

pp. 935-944 ◽

Cited By ~ 7

Author(s):

V. Zagorodnov ◽

S. Tyler ◽

D. Holland ◽

A. Stern ◽

L.G. Thompson ◽

...

Keyword(s):

Sea Water ◽

Drilling Fluid ◽

Small Diameter ◽

Working Hours ◽

Ice Shelf ◽

Drilling Equipment ◽

Drilling Technique ◽

Subglacial Lakes ◽

Minimal Environmental Impact

AbstractThis paper describes a new, environmentally friendly drilling technique for making short-and long-term access boreholes in shelf glaciers using lightweight drills. The new drilling technique was successfully developed for installation of small-diameter sensors under the Ross Ice Shelf through ~ 193 m thick ice at Windless Bight, McMurdo Ice Shelf, Antarctica. The two access boreholes were drilled and sensors installed in 110 working hours. The total weight of the drilling equipment including the power system and fuel is <400 kg. Installation of small-diameter sensors was possible for 1.8– 6 hours after penetration through the glacier into the sea water beneath. The new drilling technique does not require drilling fluid and therefore has minimal environmental impact. It should permit access through ice-shelf ice up to 350 m thick, or glaciers on grounded ice or subglacial lakes if there is no water-permeable interface at the base. Modifications, presented in this work, of the drilling equipment and protocol will allow for (1) ~ 21 working hours for penetration through 200 m of ice, (2) installation of sensors up to 120 mm in diameter and (3) drilling long-term open boreholes through 400 m thick ice in 100 working hours.

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