Optimization and Evaluation of Stabilizers for Tight Water-Sensitive Conglomerate Reservoirs.

The upper Wuerhe formation in the Mahu-1 play is a tight conglomerate reservoir that has characteristics of low porosity and low permeability. During the early stage of field development, it has been noticed that horizontal wells typically have a high flowback ratio and an extremely low oil production rate during the early production, and this is likely attributed to the water-rock interaction that causes the closure of generated hydraulic fractures. In this study, a stabilizer and its dosage in a fracturing fluid are optimized, and its effect on clay antiswelling and rock stabilization is evaluated. Experimental results indicate that a mixture of a salt and an inorganic cationic polymer can effectively inhibit the water-rock reaction by minimizing the clay swelling and compressing the electric double layer on the rock surface. The antiswelling rate of montmorillonite can reach 93.56%, and that of the reservoir rock powder can reach 75.32%. Meanwhile, Brazilian splitting tests are conducted to evaluate the mechanical property change of reservoir rocks before and after being submerged in fracturing fluids with different stabilizers. Compared to 4% KCl, which is currently used in the field, the new formula can enhance the breakdown pressure by more than 10% without increasing the cost. The findings of this work provide a solution for fracturing water-sensitive reservoirs and also establish a set of laboratory methods for optimizing stabilizers as fracturing fluid additives.

An UPLC-MS/MS method for the determination of EAI045 in plasma and tissues and its application to pharmacokinetic and distribution studies in rats.

EAI045 represents a fourth generation allosteric EGFR TKI compound which targets T790M and C797S EGFR mutants. The study reported herein describes a method to explore the distribution of EAI045 in rat tissues as well as to quantify it in plasma. The method used here is an ultra-performance liquid chromatography-tandem mass spectrometry with high sensitivity and selectivity. An ACQUITY UPLC BEN HILIC column with dimensions of 2.1 × 100 mm, 1.7 µm was used to separate the analytes and IS. As mobile phase acetonitrile as well as 0.1 % of formic acid/water was used combined with an elution gradient and 0.40 mL/min flow rate. This eluent was also used for electrospray ionization in positive ion mode. A mode on multiple reactions monitoring (MRM) was also employed in the quantification. This quantification included the use of targeted segment ions with m/z 384.1→100.8 for EAI045, and m/z 285.1→193.3 for IS, respectively. It was found that the linearity of this method was appropriate and the concentration range could be kept within a range of 2-2000 ng/mL for EAI045 in rat plasma and tissues. The level of EAI045 was found to be highest in the liver, followed by kidneys, lungs and heart. Furthermore, the results provided evidence that EAI045 could be absorbed quickly and distributed widely in different tissue types.