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Water-Based Drilling Fluid Technology for Extended Reach Wells in Liuhua Oilfield, South China Sea

Abstract To reduce the dependence of oil-based drilling fluids for extended reach well drilling, a newly developed water-based drilling fluid system has been used to drill the extended reach wells in Liuhua oilfield located in the east of the South China Sea. Based on numerous experiments, the formulations of this water-based system for various sections of extended reach wells were determined, and several key characteristics, such as lubricity, inhibition, and rheological properties, were evaluated. Using the well Liuhua 11-1-21 (A4) ERW3 as an example, the field applications of this water-based drilling fluid are elaborated in this article. Laboratory experiments and field tests indicate that this kind of specially formulated KCl/polymer system not only possesses excellent shale inhibitive character, but also has proper rheological parameters, good lubricity, and strong ability of anti-contamination for calcium ions. Hence, it can meet the demands of extended reach drilling operations in this area. A unique and integrated technology of water-based drilling fluids for extended reach well drilling in Liuhua oilfield has been formed.