Role of high-density brines in reservoir development stages:A review

High-density brines have been recognized beneficial for oilfield applications,with various key areas such as drilling,completion and formation evaluation.High-density brines can play a critical role in the development and production of oil and gas reservoirs during the primary,secondary,and tertiary recovery phases.High-density brines can enhance the mobility and recovery of the oil in the reservoir by controlling the density and viscosity.However,a less attention has been given to the application of high-density brine in the area of reservoir development.This review is shedding light on a concise overview of reservoir development stages in association with the recovery mechanisms.In addition,most possible applications of high-density fluids have also been reviewed in the field of the reservoir development.In summary,this review state that high-density brines can be used to stimulate reservoirs by hydraulic fracturing during the primary recovery phase.However,the risk of increased interfacial tension,which relies on the density difference of two fluids,can trap more residual oil relative to conventional water flooding.In addition,high-density brines are effective in decreasing the mobility ratio and facilitating favorable displacement during polymer flooding.However,they can be least effective in alkaline flooding due to the high IFT related to large density differences.Thus,it is suggested to consider the utilization of sustainable high-density brines by taking into account effective factors in petroleum engineering aspects such as stimulation,secondary recovery and polymer flooding.

Impact of methane adsorption on tight rock permeability measurements using pulse-decay

The permeability of the rock is usually measured by the injection of gas using Darcy's flow model(pulse-decay).For oil formations,helium and nitrogen are the most common gases used to measure the permeability of the rock.However,recent approaches are based on the use of methane as it minimizes the properties difference between the testing fluid and reservoir fluid.This work focused on the latter approach to compute the correction of gas adsorption.The most widely used model is Cui et al.model that is based on Langmuir adsorption isotherm.In this work,we introduced a modified model that is based on Freundlich isotherm.This model also includes the correction for gas adsorption such as Freundlich isotherms proved to be more appropriate for the adsorption on intact reservoir rock.The model is based on gas and rock properties and reduced pressure and temperature were used to accommodate the gas compressibility.The modified model can also capture effective porosity of adsorption(a)that can correct the pulse-decay storage capacity parameters a and b.The permeability estimation of ultra-tight samples using the modified approach is enhanced owing to the correction in the storage volume and rock porosity.Including the proper adsorption isotherm enhanced the porosity estimation because Langmuir isotherm yielded 11%porosity and Freundlich isotherm yielded 12%porosity.Similar results were obtained in the permeability estimation,Langmuir isotherm resulted in a 1.5%error compared to zero error in the Freundlich isotherm estimation.