A state of the art review on the performance of high-pressure and high-temperature drilling fluids: Towards understanding the structure-property relationship of drilling fluid additives

Deepwater drilling using high-pressure and high-temperature (HPHT) drilling fluids draws significant attention for the quest of increasing energy demand. In this regard, selecting appropriate drilling fluid plays a pivotal role in trouble-free and safe drilling operations. This study presents a comprehensive literature review on the performance of HPHT drilling fluids concerning the structure-property relationships of the drilling fluid additives. The advantages and disadvantages of the different categories of drilling fluids are presented. The significant features of the drilling fluids, such as their synthesis of additives, formulations, structure-property relationships, performances, process engineering, economics, and environmental aspects, are thoroughly discussed. Data for 84, 42, and 9 traditional HPHT, ultra-HPHT, and HPHT-hc drilling fluids are collected, analyzed for performance evaluation. In addition to the above drilling fluids, the performance of several high-performance drilling fluids involving ionic liquids, cationic surfactants, functionalized nanoparticles, and functionalized biopolymers are also deliberated. The present review highlights the current state in the industry, future position, and strategies for the researchers to follow. In conclusion, the top 10 high-performance HPHT drilling fluids are presented based on thermal stability, rheology, filtration loss control, lubricity, salt tolerance, and environmental aspects. It was found that the presence of (i) sulfonate, methyl, phenyl, furan, lactam, and pyrrolidine functional groups enhance thermal stability, (ii) amide, hydroxyl, cellulose derivatives, quaternary ammonium, and acrylate functional groups improve rheological performances, (iii) quaternary ammonium, pyridine, and cellulose derivatives maximize filtration control, (iv) sulfonate, acrylamide, diallyl dimethyl ammonium chloride, itaconic acid, and fatty acid esters enhance the lubrication behavior, (v) carboxylate, sulfonate, quaternary ammonium functionality, polyoxyethylene chains prevent flocculation under HPHT environment, and (vi) carboxylic acid, and sulfonic acid salts improve salt tolerance power. • Review of HPHT drilling fluids based on the structure-property relationships of mud additives. • Performance evaluation of 135 HPHT drilling fluids highlighting advantages and disadvantages. • Highlights process engineering, environmental, and cleaner production of HPHT drilling fluids. • Screening and identification of top 10 high-performance HPHT drilling fluids. • Outlines the future position and strategies for the researchers on HPHT drilling fluids.