An organic silicon filtrate reducer (AATN) with inhibitory effect, which can resist temperature up to 180℃, was synthesized by using acrylamide (AM), vinyl trimethoxysilane (A-171), allyltrimethylammonium chloride (TM) and N-vinyl pyrrolidone (NVP) as monomers. AATN can effectively reduce the filtration loss of drilling fluid and inhibit the hydration expansion and hydration dispersion of the clay, which was beneficial to wellbore stability. Experimental results showed that the API filtration loss (FLAPI) of the drilling fluid containing 2 wt% AATN was only 7.8mL. The siloxane groups of AATN were hydrolyzed in aqueous solution to generate Si-OH bonds, which can react with Si-OH bonds on hydrated clay surface to form a strong chemical adsorption. It was conducive to maintaining the dispersion of clay particles in the drilling fluid. The stable grid structure was formed by AATN and clay particles to reduce mud cake permeability, which can reduce the damage of drilling fluid filtrates to borehole stability. In addition, AATN can adsorb on the surface of sodium bentonite, thus forming a hydrophobic adsorption film on its surface, which effectively enveloped bentonite and inhibited the hydration expansion of bentonite.

In the drilling industry, the demand for environmentally friendly additives with high thermal stability is increasing due to the dual factors of increasing environmental pressure and high-temperature oil layers. However, commonly used non-toxic and biodegradable additives, such as etherified modified starch, cannot withstand temperatures higher than 150 °C. Additionally, natural polymers with better thermal stability obtained through graft modification with sulfonated monomers face challenges in meeting the standards of toxicity and biodegradability. To address these technical problems, a novel graft and crosslink copolymer, St-AA/AM/NVP/MBA (SAANM), was synthesized from corn starch by combining graft modification with a non-sulfonated monomer and cross-linking modification. Laboratory evaluation results confirm that the thermal stability of SAANM in a nitrogen atmosphere was close to 300 ℃, and it exhibits excellent temperature resistance up to 170 °C in bentonite-based mud, while also retaining the non-toxic and biodegradable characteristics of starch. The water-based drilling fluid (WBDF), added with SAANM, demonstrated outstanding rheological properties, fluid loss control performance, and environmental friendliness after aging at 170 °C and being polluted by high concentrations of NaCl or CaCl2. The successful application of SAANM in a high-temperature directional well in an offshore oil field confirms its potential for borehole cleaning and wellbore stability.

The environment-friendly water-based drilling fluid system developed for the petroleum development industry cannot successfully withstand temperatures up to 180 °C, and most high temperature-resistant additives with sulfonic acid groups that have been successfully applied to water-based drilling fluid are not good for environmental protection. In order to solve the above technical problems, a non-sulfonated filtrate reducer and viscosity reducer with resistance to high temperature were prepared by using humic acid, lignin and a multifunctional monomer as raw materials. In laboratory experiments, the molecular weights of the FLO-H filtrate reducer and the VR-H viscosity reducer were 5.45 × 105 g/mol and 8.51 × 103 g/mol, respectively, and all of them showed good high-temperature resistance. The API filtration loss of the bentonite-base slurry with 3.0 wt% FLO-H was only 6.2 mL, which indicated that FLO-H had a prominent reduction in filtration loss after aging at high temperature. When the dosage of VR-H was 1.0 wt%, the plastic viscosity of the water-based drilling fluid after aging at 200 °C decreased from 71 mPa·s to 55 mPa·s, which provided excellent dispersion and dilution. The high-temperature and high-density water-based drilling fluid containing the FLO-H filtrate reducer and the VR-H viscosity reducer had good suspension stability and low filtration performance at the high temperature of 200 °C, which can meet the requirements of high-temperature deep well drilling.

BACKGROUND It is necessary for clinicians to be aware of a rare but possible acute respiratory distress syndrome (ARDS) complication caused by multiple wasp stings. Severe ARDS has a high mortality rate but no specific pharmacotherapies have been identified to date. This case study presents the first case of severe ARDS caused by multiple wasp stings, treated successfully with extracorporeal membrane oxygenation (ECMO). It also emphasizes the effectiveness of early ECMO treatment for severe ARDS with persistent hypoxemia. CASE SUMMARY A 24-year-old woman was admitted to the emergency department after being stung by more than 10 wasps within a 30-min period, with clinical symptoms of multiple rashes, dizziness, chest tightness, nausea, and vomiting. On the 2 nd day of admission, the patient developed progressive dyspnea. The patient was diagnosed with ARDS based on clinical manifestations and lung computed tomography (CT) scan. Because of the progressive dyspnea, the intensive care unit physician performed endotracheal intubation and continued to provide ventilator support, but the patient’s respiratory distress worsened, as indicated by the ratio of arterial partial pressure of oxygen to fraction of inspired oxygen. Veno-venous ECMO was initiated for 6 d. On day 7 of admission, ECMO was stopped. On the 11 th day of admission, CT scan of the lungs revealed significant reduction of ground-glass opacities and consolidations. After about 2 wk, the patient recovered completely from ARDS and was discharged to home. At the 2-mo follow-up, the patient was in good health with no recurrence of dyspnea nor chest tightness. CONCLUSION ARDS complication caused by multiple wasp stings may be fatal when mechanical ventilation becomes dangerous due to persistent hypoxemia and despite optimization of ARDS management. We propose that the early implementation of ECMO is a relatively effective treatment, although the evidence is relatively limited.