Studies and Application of Slag-Blocking Agent for Steam-Injection Reservoir

Abstract With the technique of steam flooding widely used in heavy oil recovery in Xinjiang Oilfield, a noticeable steam channeling mainly caused by the heterogeneity of the reservoir and the steam overlay has been observed, which in most cases can result in a rapid increase of water cut and even in a direct production of steam in the wells. To enhance the utilization of the steam and heavy oil recovery, this work puts forward the technique of slag blocking agent for steam injection reservoir. Based on the compositions and properties of industrial slag with silicate as the main component, the activation system, the high temperature retardant and the suspension system have been developed accordingly. The systematic investigations have been carried out on such properties of blocking agent as suspension stability, injection characteristic, initial setting time, thickening process and setting strength. The high-temperature blocking agent developed is of characteristics of better stability, easy preparation, low cost, controllable setting time and convenient in-situ operation. The field experiments were further conducted by applying the blocking agent to the selected 4 wells with observable occurrence of steam channeling in the steam injection heavy oil reservoir. The results show that the blocking agent has an excellent ability to plug the gas-channeling path, thus mitigating the steam channeling and expanding the sweep of injection steam. The good results of an increase of 3,776t oil production and a reduction of 1.5×104m3 water production have been obtained eventually.