ABSTRACT:The chemical grafting of polyaniline, poly(oanisidine), and poly(o-toluidine) on polyester fabric was carried out with ammonium peroxodisulfate in an acidic medium. The formation of the grafted fabric substrate was confirmed with reflectance spectroscopy, Fourier transform infrared spectroscopy, weight-loss studies, and conductivity measurements. The grafting percentage and efficiency percentage were determined for the different grafted substrates. The thermal and flame-retardant properties of these grafted substrates were elucidated. Thermogravimetric analysis thermograms and derivative thermogravimetry curves showed that the grafted substrates had a higher thermal stability and char-residue percentage at 700°C. The grafted substrates showed a higher activation energy of thermal decomposition than the nongrafted substrates. The grafted substrates showed good flame retardancy, which was evident from the increase in the limited oxygen index in comparison with that of the nongrafted substrate.

No abstract

Excessive water production from unwanted zones in oil producing wells is one of the major challenges faced by the oil industry. The applicability of organically crosslinked polymer (OCP) systems as sealants for water shutoff treatments in temperatures up to 350°F is well documented. However, their effectiveness at temperatures above 350°F has not been evaluated. This paper presents experimental data from using an OCP system for water shutoff treatments at 400°F.At temperatures around 400°F, crosslinking is expected to happen faster and can lead to premature gelation of the recipe before the entire treatment is in place. Thus, controlling the gelation time at such temperatures is extremely crucial. Optimizing the amount of retarder is essential to provide adequate time for placement of the treatment fluid. This paper provides gelation time data at temperatures between 350 and 400°F with different amounts of retarder. With an optimum amount of retarder, the OCP showed a gelation time of 1 hr 20 min. This paper also describes the experimental setup used to study and determine the long-term stability of the OCP system at 400°F. Sand packs measuring 1-ft long were used for the test to simulate formation conditions. Once the optimized OCP recipe was gelled inside the sand pack, measurements were taken by gradually applying incremental differential pressure (ΔP) to evaluate the sealant at temperature, as well as the threshold ΔP the system could withstand. Even after one month at 400°F, the OCP recipe was able to sustain a ΔP of 950 psi over the sand pack.The data indicates the applicability of this system as an effective conformance product to shut off water-producing zones over an extended period of time at 400°F.

Precipitation of asphaltene is a serious and common challenge faced by the oil industry during production of heavy oil. Regular treatments are often required to reinstate lost productivity by removal of such deposits from tubing or within the reservoir. Hydrocarbon-based solvents, like xylene or xylene mixtures, are the most commonly used recipes for dissolution of deposited asphaltenes. While such treatments are effective, they sometimes present problems with respect to health, safety, and environmental (HSE) characteristics (lower flash points and the presence of benzene, ethyl benzene, toluene, or xylene (BETX) components), which can limit their use. Recently, water/solvent emulsion systems that offer significant advantages compared to traditional recipes have been used. The solvents used in these emulsions have relatively higher flash points, making them a safer alternative. Further, the redeposition process is delayed because the treated surfaces are left in a water-wet condition. This paper describes the application of such water/solvent emulsion systems used to treat asphaltene deposits from two distinct regions of the eastern hemisphere. The steps taken to optimize a recipe suitable for dissolution of the asphaltene deposits are highlighted. This is extremely important to the design of a successful treatment because the complexity of the deposits vary regionally. Higher solubility values were obtained with the emulsion system when compared to xylene. Importantly, these emulsion systems could also be designed with acid as an aqueous phase. This increases the solubility values significantly because acid-soluble inorganic minerals were also found in conjunction with asphaltene in the deposits studied. The data presented demonstrates the applicability of the emulsion system for effective removal of asphaltene deposits and recovery of lost productivity. This environmentally acceptable emulsion system can contribute significantly to profitable and sustained production of heavy oil when faced with asphaltene challenges.