Zhanna Kazakbayeva | Nazarbayev University (original) (raw)

Papers by Zhanna Kazakbayeva

Research paper thumbnail of Successful Implementation of Managed Pressure Drilling and Managed Pressure Cementing Techniques in Fractured Carbonate Formation Prone to Total Lost Circulation in Far North Region

Day 1 Tue, November 23, 2021, 2021

Drilling reservoir section in the oilfield located in Far North region is challenged with high ri... more Drilling reservoir section in the oilfield located in Far North region is challenged with high risks of mud losses ranging from relatively minor losses to severe lost circulation. Numerous attempts to cure losses with traditional methods have been inefficient and unsuccessful. This paper describes implementation of Managed Pressure Drilling (MPD) and Managed Pressure Cementing (MPC) techniques to drill 6-1/8″ hole section, run and cement 5″ liner managing bottomhole pressure and overcoming wellbore construction challenges. Application of MPD technique enabled drilling 6-1/8″ hole section with statically underbalanced mud holding constant bottom hole pressure both in static and dynamic conditions. The drilling window uncertainty made it difficult to plan for the correct mud weight (MW) to drill the section. The MW and MPD design were chosen after risk assessment and based on the decisions from drilling operator. Coriolis flowmeter proved to be essential in deciphering minor losses an...

Research paper thumbnail of Homolytic C–Br bond dissociation energies obtained by means of the G4 thermochemical protocol

Chemical Data Collections, 2016

Abstract Knowledge of the energies required to induce homolytic cleavage of the C–Br bonds of bro... more Abstract Knowledge of the energies required to induce homolytic cleavage of the C–Br bonds of brominated organic molecules, a process that affords carbon-centered radicals and Br • , is of fundamental importance. Although some data pertaining to the strength of C–Br bonds can already be found in the literature, the chemical diversity of the species for which bond dissociation energies (BDEs) are available is somewhat limited. In this data article, we report a comprehensive set of homolytic C–Br BDEs, obtained using the G4 thermochemical protocol, for brominated organic molecules with wide structural diversity. The species in this set have C–Br BDEs (at 298 K) that differ by as much as 188.3 kJ mol –1 , with α-bromoalanine having the lowest BDE (214.1 kJ mol –1 ) and 1-bromobut-1-yne having the largest (402.4 kJ mol –1 ). Of particular relevance to biological systems are the BDEs of 8-bromoguanine (345.3 kJ mol –1 ), 8-bromoadenine (345.6 kJ mol –1 ), 5-bromocytosine (348.8 kJ mol –1 ) and 5-bromouracil (350.3 kJ mol –1 ).

Research paper thumbnail of Formation of type III Deep Eutectic Solvents and effect of water on their intermolecular interactions

Fluid Phase Equilibria, 2017

Several novel applications of Deep Eutectic Solvents (DESs) have emerged recently. With a growing... more Several novel applications of Deep Eutectic Solvents (DESs) have emerged recently. With a growing interest in the field, there is an urge to understand formation and functioning of these solvents at molecular level, which in turn would assist in further designing of DESs. We herein performed molecular dynamics simulations on three of the commonly used type III DES, viz, reline, ethaline, and glyceline, which are mixtures of urea, ethylene glycol, and glycerol with choline chloride at eutectic composition. Our results explain the role of inter-molecular and intra-molecular hydrogen bonding and energies on formation of these DESs. Furthermore, the ability of these DESs to be altered in a desired way through a simple addition of water makes it versatile solution for several other applications. Hence, simulations are also performed on the aqueous DES solutions, which reveal the effect of water on intermolecular network of interaction existing within these DESs.

Research paper thumbnail of Successful Implementation of Managed Pressure Drilling and Managed Pressure Cementing Techniques in Fractured Carbonate Formation Prone to Total Lost Circulation in Far North Region

Day 1 Tue, November 23, 2021, 2021

Drilling reservoir section in the oilfield located in Far North region is challenged with high ri... more Drilling reservoir section in the oilfield located in Far North region is challenged with high risks of mud losses ranging from relatively minor losses to severe lost circulation. Numerous attempts to cure losses with traditional methods have been inefficient and unsuccessful. This paper describes implementation of Managed Pressure Drilling (MPD) and Managed Pressure Cementing (MPC) techniques to drill 6-1/8″ hole section, run and cement 5″ liner managing bottomhole pressure and overcoming wellbore construction challenges. Application of MPD technique enabled drilling 6-1/8″ hole section with statically underbalanced mud holding constant bottom hole pressure both in static and dynamic conditions. The drilling window uncertainty made it difficult to plan for the correct mud weight (MW) to drill the section. The MW and MPD design were chosen after risk assessment and based on the decisions from drilling operator. Coriolis flowmeter proved to be essential in deciphering minor losses an...

Research paper thumbnail of Homolytic C–Br bond dissociation energies obtained by means of the G4 thermochemical protocol

Chemical Data Collections, 2016

Abstract Knowledge of the energies required to induce homolytic cleavage of the C–Br bonds of bro... more Abstract Knowledge of the energies required to induce homolytic cleavage of the C–Br bonds of brominated organic molecules, a process that affords carbon-centered radicals and Br • , is of fundamental importance. Although some data pertaining to the strength of C–Br bonds can already be found in the literature, the chemical diversity of the species for which bond dissociation energies (BDEs) are available is somewhat limited. In this data article, we report a comprehensive set of homolytic C–Br BDEs, obtained using the G4 thermochemical protocol, for brominated organic molecules with wide structural diversity. The species in this set have C–Br BDEs (at 298 K) that differ by as much as 188.3 kJ mol –1 , with α-bromoalanine having the lowest BDE (214.1 kJ mol –1 ) and 1-bromobut-1-yne having the largest (402.4 kJ mol –1 ). Of particular relevance to biological systems are the BDEs of 8-bromoguanine (345.3 kJ mol –1 ), 8-bromoadenine (345.6 kJ mol –1 ), 5-bromocytosine (348.8 kJ mol –1 ) and 5-bromouracil (350.3 kJ mol –1 ).

Research paper thumbnail of Formation of type III Deep Eutectic Solvents and effect of water on their intermolecular interactions

Fluid Phase Equilibria, 2017

Several novel applications of Deep Eutectic Solvents (DESs) have emerged recently. With a growing... more Several novel applications of Deep Eutectic Solvents (DESs) have emerged recently. With a growing interest in the field, there is an urge to understand formation and functioning of these solvents at molecular level, which in turn would assist in further designing of DESs. We herein performed molecular dynamics simulations on three of the commonly used type III DES, viz, reline, ethaline, and glyceline, which are mixtures of urea, ethylene glycol, and glycerol with choline chloride at eutectic composition. Our results explain the role of inter-molecular and intra-molecular hydrogen bonding and energies on formation of these DESs. Furthermore, the ability of these DESs to be altered in a desired way through a simple addition of water makes it versatile solution for several other applications. Hence, simulations are also performed on the aqueous DES solutions, which reveal the effect of water on intermolecular network of interaction existing within these DESs.