Streamlines based methodology for determining the acidity balance of solutions of technological blocks developed by in-situ leaching

Abstract

The in-situ leaching is a method of developing low-concentration ore deposits occurring in permeable rocks by pumping a leaching solution into the reservoir through injection wells, which dissolve the mineral in situ and pumping the productive solution to the surface through pumping wells. During development, the deposit is divided into technological blocks; developments of each block could be independent from others. To improve the environmental friendliness of work and prevent the spreading of solutions beyond the boundaries of the block, a balance of solutions is observed, i.e. the volumes of injected leaching and pumped out productive solution should be equal. In this connection, the question arises of calculating flow rates at injection wells in adjacent blocks. Currently, the distribution of flow rates of injection wells in adjacent technological blocks is calculated by averaging the extraction wells interacting with a given well. However, the accuracy of this calculation is quite low, since it does not take into account both the reservoir properties and the distances between wells. In this connection, in this paper, it is proposed to calculate well flow rates based on modeling, based on the fundamental laws using streamlines. Thus, the proposed technique makes it possible to take into account the direction of the flow of the solution and the filtration properties of the rock.