Formation Damage From Fine Particulate Invasion: An Example From the Lost Soldier Tensleep Formation

This paper reports on the Tensleep formation in the Lost Soldier field that has been pattern waterflooded since 1976. Injection wells have historically exhibited large declines in injectivity and required frequent workovers. Because those declines were originally attributed to near-well damage from poor injection-water quality, a cleanup program was initiated that significantly reduced the amount and size of suspended particles in the injection water. Despite these improvements, injectivity continued to decline in many wells. Subsequent analyses of well histories, pressure-falloff tests, and reservoir petrophysical properties suggest that the reservoir damage in many instances was not only a sandface phenomenon, but also a result of deep particle invasion. Workover procedures were altered to treat the formation beyond the near-wellbore area, resulting in increased injectivities compared with the historical norm.