Polymeric formulations used for loss circulation materials and wellbore strengthening applications in oil and gas wells: A review

Drilling fluid circulation loss is referred to as the most severe problem in drilling of oil and gas wells, as a routine solution, loss circulation materials are added to fill any fractures and vugs that may have been created during the drilling process. An alternative technology to control drilling fluid loss is Wellbore Strengthening as a set of engineering design solutions to seal and plug near-wellbore fractures efficiently. This review presents polymeric systems used as loss circulation materials (LCMs) or in wellbore strengthening applications. Moreover, factors that affect the strength of the polymeric formulations, compatibility with drilling fluid and additives, rheological properties and thermal stability are discussed. In addition to that, the review highlights the use of nano-materials in loss circulation polymeric systems. The performance evaluation methods used to evaluate the polymer gel properties are reviewed and the main characteristic of successful LCM formulations are highlighted. Polymers applied in other oil and gas operations, such as hydraulic fracturing and cementing, that have a potential for use in LCM applications are also included in this review.