Judul: Formulasi Surfaktan Metil Ester Sulfonat sebagai Oil Well Cleaning
Abstrak: Oil productivity reduction may be due to plugging in the oil rock formations. The plugging may be caused by the deposition of paraffin, asphaltene, and scale. Problem caused by the presence of the precipitate is the rock formation can be oil wet so that oil permeability decreases. The problem can be solved by well cleaning technique with surfactant formula. Surfactant MES is a type of anionic surfactant which has ability to lower the interfcial tension, surface tension, and able to change the properties of rock from oil wet to become water wet. Surfactant MES formula for well cleaning requires carrier agent. In this study, diesel oil and metil ester were used as carrying agent. Aromatic solvents were also needed. Xylene and toluene has ability to dissolve asphaltene that deposites in formation. Surfaktan formulation for well cleaning was done with several stages, those are determine the SMES concentration and aromatic solvents concentration. Surfactant performance tests for oil well cleaning were thermal stability, phase behavior, and wettability. The surfactant formula which gave the best performance was SMES 3% in metil ester carrying agent with xylene 15% as additive.
Keyword: methyl sulfonic esters, oil well cleaning, Asphaltene

Judul: Formulasi Surfaktan MES Sebagai Acid Stimulation Agent untuk Lapangan Karbonat (Studi Kasus: Lapangan T)
Abstrak: The decrease of oil well productivity can be affected by the scale blockage and the conditions inside of the oil well. This problem can be solved by stimulating the oil well with an acid stimulation agent. This chemical solution contains of surfactant, brine, and acid. The surfactant reduces the interfacial and surface tension, the brine dissolves the surfactant, and the acid has a function as carbonate scale solvent. This research was conducted to find the formula of acid stimulation agent that gives the best performance to improve the oil well productivity. The materials used in this research were the oil well fluids that consist of formation water and crude oil from T oil field. The surfactants (MES and SMES) concentration used in this research was 0.5%, 1%, 1.5%, 2%; 3%, 4%, 5%, and 6% (w/w). HCl concentration added to surfactant solution were 5%, 10%, and 15% (w/w). At the last, 2% CH3COOH was added to this formula. The formula that gave the best performance was SMES 4% + HCl 5% + CH3COOH 2% with IFT value 6.74x10-2 dyne/cm and the solubility degree 20.7%. This formula has good resistance to high temperature of 90oC and has good capability of changing the core wettability to become more water-wet.
Keyword: acid stimulation agent, acid, methyl ester sulphonate, carbonate scale

Judul: Pengukuran Jantung Kelinci New Zealand White (Oryctolagus cuniculus) dengan Radiografi Toraks
Abstrak: This research was conducted to evaluate radiographs heart size of anaesthetized New Zealand White rabbits (Oryctolagus cuniculus) under different combination of ketamine and xylazine. The rabbits were divided into three groups. Group A were anaesthetized using a 35 mg/kg and 5 mg/kg combination of ketamine and xylazine (n=5). Group B were anaesthetized using a 40 mg/kg and 5 mg/kg combination of ketamine and xylazine (n=3) while group C were anaesthetized using 45 mg/kg and 5 mg/kg combination of ketamine and xylazine (n=3). Parameter of observation from left laterolateral view were: 1) the apicobasilar length of the heart (AB), 2) the width of the heart (CD), 3) the distance between the cranial edge of the fifth rib and the caudal edge of the seventh rib perpendicular to the spine (R5-7), and 4) the vertical depth of the toraks (H). Parameter of observation from dorsoventral view were: 1) the length of the heart (L), 2) the width of the heart (W), and 3) the width of the thorax (T). The result from the heart parameters observation that were measured in left laterolateral view and dorsoventral view shows theres no significantly differ among the groups (P > 0.05). The vertebrae heart size (VHS) values obtained from the sum of the length of the long and the short axes on left laterolateral view. The long axes mean values (A) were 4.35±0.26 v and the short axes mean values (B) were 3.59±0.30 v, therefore VHS mean values were 7.94±0.49 v. On the dorsoventral view, the length of the heart mean values (L) were 4.32±0.29 cm, the width of the heart mean values (W) were 3.33±0.26 cm, and the width of the thorax mean values (T) were 5.85±0.30 cm. In normal conditions, the width of the heart should be less than two-thirds the width of the thorax and values obtained of 3.33<3.72 it shows that the heart is in the normal range. The best ratio to calculated the normal heart dimension in the left laterolateral view was compared the long axes with the vertical depth of the thorax, whereas in dorsoventral view, the length of the heart was compared with the width of the heart.
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