DUAL DOWNHOLE INJECTION SYSTEM UTILIZING COILED TUBING

摘要

A dual injection system for selectively injecting a treating fluid in a predeterminedtreating zone (16) of a well bore hole (10) adjacent a productive zone (14) with a markerfluid injected from the annulus (36) outside a coiled tubing string (34). The coiled tubingstring (34) is inserted within the well bore hole (10) and a sensor (40) is provided on thecoiled tubing string (34) with a lower end portion (42) extending below the sensor (40) forthe discharge of the treating fluid from the lower end (44) of the extending end portion (42).The sensor (40) senses a detectable material, such as a radioactive material in themarker fluid injected from the annulus (36) outside the coiled tubing string (34) and maybe reciprocated within the well with the coiled tubing string (34) for determining theinterface (46) between the marker fluid and the treating fluid so that the treating fluid doesnot enter the productive zone (18). In one embodiment (Figure 4) the productive zone(14A) is located below the treating zone (16A) and the treating fluid contains the markerto provide the marker fluid.