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Hydraulic Fracking:The Process
Published in Frank R. Spellman, Hydraulic Fracturing Wastewater, 2017
The key to a rotary drill’s speed is the relative ease of adding new sections of drill pipe (or drill string) while the drill bit continues turning. Drilling mud (fluid) circulates down through the center of the hollow drill pipe and up through the wellbore to lift the drill cuttings to the surface. Modern drill bits are studded with industrial diamonds to make them abrasive enough to grind through any rock type. From time to time, the drill string must be removed (a process termed tripping) to replace dulled drill bits.
The influence of nanoparticles with KCl salt on improving of water-based drilling fluid properties: experimental analysis and trial field test
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Majid Sajjadian, Vali Ahmad Sajjadian, Alimorad Rashidi
FMWCNTs and FNPG were used to progress water-based drilling fluid characteristics. Basing on density, rheology, and filtration analysis, FMWCNTs and GNP as individually and mixture are possibility replacements as a chemical additive in the WBDF design. In this experimental research, the outcomes indicated that the presence of FMWCNTs and FNPG proved a negligible influence on drilling fluid weight. The fluid sample used the mixture of NPs presents an enhancement in YP up to 61%. Both NPs agents used simultaneously also could reduce the mud filtration volumes up to 54 and 74%, in comparison with the rest of mud samples without mentioned NPs in LPLT and HPHT temperature in order. The results taken demonstrated that using NPs could successfully increase the thermal tolerance at higher temperatures up to 230°C (450°F) as presented by progressed and stabilized their rheological properties after a hot aging experiment. It also found that the mud cake characteristics such as thickness and surface texture quality are improved with using of FMWCNTs and FNPG. Field application is accomplished in a well of Iranian field, which shows suitable influence in hole stability and cleaning, no tight hole during tripping, no too much tripping, and no hole filling while a trip in the hole and drill string sticking in the drilling process. This drilling mud could face the requirements of HPHT well drilling in one of the most problematic fields. Lastly, according to experimental analysis and field trial test can be concluded that the mixture of both NPs improved the overall efficiency of the drilling process by reducing NPT. The influence of mentioned nanoparticles on improving of oil-base drilling fluid properties will be evaluated for next research in future. Also, the mixture of other kinds of nanoparticles as drilling fluid additives cloud investigate for subsequent studies.
Offshore drilling blowout risk model – an integration of basic causes, safety barriers, risk influencing factors and operational performance indicators
Published in Safety and Reliability, 2018
Pedro Perez, Guido Dalu, Natalia Gomez, Henry Tan
The next stage of a drilling project is the well construction, the beginning of which is known in the industry as ‘spud-in’. This stage consists of four main activities: drilling, tripping, casing and cementing. Drilling and tripping operations can be described as geological layers being drilled through by a rotating drill bit, connected to a drill string (a string made up of drill pipe joints, working in tension and transmitting torque to the bit), which applies part of its weight to the formation. The drilling fluid (or mud) is pumped at pressure through the string with the purpose of overcoming pressure losses, achieving minimum annular velocity that ensures hole cleaning (cutting transportation to surface) and balancing formation pressure in specific operational conditions:Static conditions: pumps off;Swab effect: small clearance between BHA and borehole walls jointly with fluid viscosity lead to a negative pressure when pulling the string, reducing the amount of overbalance and potentially causing a kick;Surge effects: opposite of swab, leading to excessive overbalance hence fluid losses or fracturing;Impact of cutting loading (suspended cuttings of high specific gravity) on equivalent mud weight (EMW) increase;Trip margin: amount of additional MW required as a safety margin prior to POOH string (in case of a kick, well control is much more difficult without string in the hole, due to the impossibility to circulate);Equivalent circulating density (ECD): the effective density exerted by a circulating fluid against the formation that takes into account the pressure drop in the annulus above the point being considered.