Paraffin hard solid

Asphaltene-resin-paraffin deposition (ARPD) is a complicated and prevalent issue in oil and gas industry, impacting the efficiency, integrity of petroleum extraction, production, transportation and processing systems. Considering all witnessed ARPD problems in Azerbaijan oil fields, this paper proposed a chemical method and optimized the type and the concentration of chemical inhibitors. And then the effect of selected chemical reagent on inhibiting the ARPD amount and thus en-hancing oil recovery was detected by reservoir simulation during both waterflooding and CO2 flooding production. Three new chemical compounds (namely, Chemical-A, Chemical-B and Chemical-C) were examined in laboratory conditions and their impact on rheological properties of high-paraffin oilfield samples of Azerbaijan (X, Y and Z) were investigated. Experimental results show that Chemical-C with concentration of 600 g/t has the best efficiency for alleviating the problems. After adding Chemical-C to the crude oil, the freezing point of oil is decreased from 12 °C to (-4) °C, ARPD amount is declined from 0.185 to 0.016 g and oil effective viscosity is reduced from 16.2 mPa·s to 3.1 mPa·s. It is determined that for water and CO2 flooding, higher injection pressure resulted in reduced asphaltene precipitation. Adding selected ARPD inhibitor, the oil recovery for waterflooding can increase from 52% to 62%, while it can rise from 55% to 68% for CO2 flooding.

Abstract licence: CC BY 4.0

Objectives: This study aimed to determine the factors affecting the diagnostic efficacy of frozen sections for assessing tumor spread through air spaces (STAS) and to provide suggestions for the sampling of these frozen sections. Methods: Cases of invasive adenocarcinoma with a pathological diagnosis of stage IA-IIIB were screened, and frozen and paraffin sections were reviewed. Using paraffin sections as the gold standard, the consistency of frozen pathological diagnosis of STAS was calculated. Factors that may affect STAS diagnosis in frozen sections were screened, and a nomogram was drawn. Results: The sensitivity of frozen sections in STAS diagnosis was 55.4% (108/195), the specificity was 74.5% (254/321), and the kappa value was 0.35. In the subsequent logistic regression, the ratio of the tissue diameters of the frozen and paraffin sections, number of frozen section sheets, clarity of the tumor boundary, and number of alveoli from the peritumoral area to tissue edge were all statistically significantly significant (p Conclusions: The diagnostic efficacy of frozen sections for STAS is poor. In our study, the tissue diameter ratio of the frozen to paraffin sections, the number of frozen sections, the clarity of the tumor boundary, and the number of alveoli from the peritumoral tissue to the tissue edge were considered independent factors affecting diagnostic consistency. The accuracy of the frozen section analysis in STAS diagnosis can be improved by our reasonable suggestions on frozen sampling, making it a reliable indicator of the surgical method.

Abstract licence: CC BY