Evaluation of Reservoir Performance under Water Injection Considering the Effect of Inorganic Scale Deposition in an Iranian Carbonate Oil Reservoir

Abstract

Abstract Water injection is one of the main oil recovery techniques, which usually associated with problematic and challenging formation damage concerns including mineral scale deposition, organic scale, clay swelling, particle invasion, fine migration and microbial damage. These concerns usually significantly affect the performance of water injection scenarios by reduction of production rate and therefore ultimate recovery. In this work, mineral scale deposition phenomenon due to sea water injection and its influence on productivity loss and the reservoir performance of an Iranian offshore carbonate oil reservoir have been investigated. This filed has been producing by water injection since 1985. During these years the field has facing several formation damages mechanisms especially mineral scale deposition. For this purpose, a simulation study using solid deposition module of Eclipse 100 (v. 2006) has been conducted to simulate various phenomena occurring in the reservoir due to water injection, which undermines the oil production rate. As input of the simulation, the actual amount and concentrations of scale formed due to mixing of various portions of formation and injected sea waters and the productivity index reduction due to injection of different water mixtures are needed. These data must be experimentally measured in an actual bulk and core media for the studied reservoir. Comprehensive laboratory studies have been, therefore, conducted to obtain the simulation required information. These data have been incorporated into the simulation model to evaluate the scale deposition effects. The simulator enables to model the mixing zone, mineral scales precipitation, reservoir performance and productivity index reduction due to sea water injection process. The results show that the production loss due to scale deposition can be predicted/simulated reliably by using the applied methodology and appropriate required experimental works.