Evaluation of Various Designs for Scale Inhibition Squeeze Treatments in Carbonate Reservoirs

Abstract

Scale is considered as one of the major concerns in the oilfield industry. Usually, scale formation causes several issues such as: reduced production, formation damage, jeopardizing well integrity, and causing damage to assets such as artificial lift equipment. Therefore, a scale inhibition operation has to be conducted to sustain oil and gas production by assuring the flowing conditions of the reservoir and production assets. Scale inhibition in oilfield industry is carried out in one of four ways: 1- squeezing the inhibitor inside the formation, 2- continuously injecting the inhibitor through a capillary tubing, 3- apply an encapsulated inhibitor in the rat hole, 4- applying batch treatments. In this study, we are evaluating various treatment designs for the scale inhibition through the squeezing technique in terms of efficiency and lifetime. The efficiency of scale inhibition squeeze treatments is bound to a certain lifetime which depends on the interaction between the inhibitor and the reservoir rock. The inhibitor interacts with the rock in an adsorption fashion, then it desorbs to maintain a certain concentration in the aqueous portion of the produced fluids; thus, inhibiting scale deposition. When squeezing the scale inhibitor deep inside the reservoir, the inhibitor has a greater surface area to adsorb onto; therefore, less of it will be retained when flowing the well after the operation. The drawback of the squeeze technique is the duration, and the inhibitor loss right after the operation, the greater the inhibitor production the shorter the treatment lifetime. Squeezing the treatment deep inside the formation has reduced the inhibitor concentration; thus, increased the treatment estimated lifetime by almost 5 folds.