For several decades, wells drilled in Block 6, Sudan, have experienced serious hole-instability problems related to drilling fluids due to the highly reactive and dispersive shales that exist in the Aradeiba and Abu G...For several decades, wells drilled in Block 6, Sudan, have experienced serious hole-instability problems related to drilling fluids due to the highly reactive and dispersive shales that exist in the Aradeiba and Abu Gabra formations. These problems included washout hole sections combined with tight holes, as well as serious sloughing. Frequent wiper trips were required and logging of the wells was not usually successful. Previously, several conventional inhibitive water-based drilling fluids such as KCl/polymer, KCl/lime/polymer and KCl/PHPA （partially hydrolyzed polyacrylamide） have been used in this area, but with only marginal improvements in hole stability and drilling performance. Recently, a newly formulated KCl/sodium silicate system, which is characterized by the good rheological properties and filtration control, was developed and used for providing the necessary inhibitive character. The first trial well was drilled with this kind of drilling fluid in Block 6, Sudan, and the following benefits were observed： （1） Excellent integrity exhibited by drilled cuttings for shale formations; （2） Stable borehole kept with lower mud weight; （3） Reduced wiper trips; and （4） In-gauge borehole shown from caliper logs. Later on, five more wells were drilled with the KCl/sodium silicate system in this area. It was found that the KCl/sodium silicate system can fully meet the demands of drilling operations in this area. Case studies are presented in this paper in terms of wiper trips, inhibitive character of cuttings, hole conditions and mud weight.展开更多
The present work aimed to synthesize a new interesting series of thiazole based polyamides containing diarylidenecyclohexanone moiety 5a-5f using low temperature solution polycondensation technique. The new polymers w...The present work aimed to synthesize a new interesting series of thiazole based polyamides containing diarylidenecyclohexanone moiety 5a-5f using low temperature solution polycondensation technique. The new polymers were synthesized by the reaction of thiazole based monomer namely, bis（2-aminothiazol-4-ylbenzylidene）cyclohexanone 3 with different aliphatic and aromatic diacid chlorides using NMP, and in the presence of anhydrous Li Cl as catalyst. Adipoyl, sebacoyl, oxaloyl, terephthaloyl, isophthaloyl dichlorides and biphenyl dicarbonyl dichloride were used as diacid chlorides. The structure of the model compound 4 as well as the new polymers was confirmed by correct elemental and spectral analyses. The thermal properties of those polymers were evaluated by TGA and DTG measurements and correlated to their structural units, beside X-ray diffraction analysis, solubility and viscometry measurements. The inherent viscosities for the synthesized polymers were in the range 0.6–1.03 d L/g. On the other hand the corrosion inhibitive properties of monomer 3 as well as polyamides 5d and 5f as selected examples were carried out on carbon-steel in 0.5 mol/L H2SO4 at 40 °C. The calculated inhibition efficiency（IE%） for polymer 5d was in the range（82 ± 6）% in all selected concentrations. The best value of IE% was obtained at 1 mg/L to reach 98.24% for polymer 5d and at 0.5 mg/L to reach 87.75% for polymer 5f.展开更多
文摘For several decades, wells drilled in Block 6, Sudan, have experienced serious hole-instability problems related to drilling fluids due to the highly reactive and dispersive shales that exist in the Aradeiba and Abu Gabra formations. These problems included washout hole sections combined with tight holes, as well as serious sloughing. Frequent wiper trips were required and logging of the wells was not usually successful. Previously, several conventional inhibitive water-based drilling fluids such as KCl/polymer, KCl/lime/polymer and KCl/PHPA （partially hydrolyzed polyacrylamide） have been used in this area, but with only marginal improvements in hole stability and drilling performance. Recently, a newly formulated KCl/sodium silicate system, which is characterized by the good rheological properties and filtration control, was developed and used for providing the necessary inhibitive character. The first trial well was drilled with this kind of drilling fluid in Block 6, Sudan, and the following benefits were observed： （1） Excellent integrity exhibited by drilled cuttings for shale formations; （2） Stable borehole kept with lower mud weight; （3） Reduced wiper trips; and （4） In-gauge borehole shown from caliper logs. Later on, five more wells were drilled with the KCl/sodium silicate system in this area. It was found that the KCl/sodium silicate system can fully meet the demands of drilling operations in this area. Case studies are presented in this paper in terms of wiper trips, inhibitive character of cuttings, hole conditions and mud weight.
文摘The present work aimed to synthesize a new interesting series of thiazole based polyamides containing diarylidenecyclohexanone moiety 5a-5f using low temperature solution polycondensation technique. The new polymers were synthesized by the reaction of thiazole based monomer namely, bis（2-aminothiazol-4-ylbenzylidene）cyclohexanone 3 with different aliphatic and aromatic diacid chlorides using NMP, and in the presence of anhydrous Li Cl as catalyst. Adipoyl, sebacoyl, oxaloyl, terephthaloyl, isophthaloyl dichlorides and biphenyl dicarbonyl dichloride were used as diacid chlorides. The structure of the model compound 4 as well as the new polymers was confirmed by correct elemental and spectral analyses. The thermal properties of those polymers were evaluated by TGA and DTG measurements and correlated to their structural units, beside X-ray diffraction analysis, solubility and viscometry measurements. The inherent viscosities for the synthesized polymers were in the range 0.6–1.03 d L/g. On the other hand the corrosion inhibitive properties of monomer 3 as well as polyamides 5d and 5f as selected examples were carried out on carbon-steel in 0.5 mol/L H2SO4 at 40 °C. The calculated inhibition efficiency（IE%） for polymer 5d was in the range（82 ± 6）% in all selected concentrations. The best value of IE% was obtained at 1 mg/L to reach 98.24% for polymer 5d and at 0.5 mg/L to reach 87.75% for polymer 5f.
