Drilling Fluids For High Permeability Sandstone Reservoirs Protection

High permeability in sandstone reservoir, high clay content, severe heterogeneity, ease of liquid invasion into the well-bore, shale water sensitivity are among the various causes of reservoir damage. This work dealt a characterization of reservoir damage of Hade oilfield mainly formed of Carboniferous sandstone as well as investigating the suitable drilling mud system used for reservoir protection purpose. The laboratory experiments showed that, solid intrusion, water sensitivity, and the filtrate fluid are the predominant causes leading to damage the formation. Moreover, results also revealed that, the couple KPAM/ /KC with a ratio of 2: 1 when used as mud additives demonstrated excellent inhibitor of shale water sensitivity with an anti-swelling rate of 93.5%. Furthermore, an appropriate combination of polysulfonate used as temporary blocking additives and a film forming mud additives were enabling to achieve appreciable sealing properties. Through out the results, the newly developed drilling mud system was demonstrated effective performance in terms of reservoir protection.