Injection Well Refrac with LWI Enhances Well Injection Performance

Abstract Objectives/Scope Operators face many challenges maintaining injection rates into water injection wells. One example is to get the required rates may include injecting off spec water, which can create scaling, or solids buildup in the tubing. Small fracture geometry can also be a factor. A Deepwater GOA operator was facing issues in their well that was plagued with low injection rates from the initial completion. Though the operator was trying to inject above fracturing rates, the amount of water that was able to be injected was well below the amount needed for reservoir voidage replacement. Methods, Procedures, Process A damage mechanism assessment was performed which included a problem-solving exercise and lab evaluations of a visoelastic surfactant (VES) gravel pac fluid that was selected for its clean breaking characteristic since no flowback of this well is possible. Also discovered during lab testing was the potential for scale to be formed after analyzing the seawater being injected. Economic evaluation on this well was more difficult than that of an oil well due to having to estimate what the future uplift would be for producers in the field. A plan was formulated to include an HF acid to clean out the perforations followed by a high viscosity breakdown using a (VES) fluid to create a larger frac geometry in each formation. Since this well had two separate zones within the smart well completion they were treated individually. Frac modeling was also conducted to estimate the frac geometry. This information was then entered into a reservoir simulation model to understand how it would potentially translate into additional oil production from the producing wells. Results, Observations, Conclusions This well was being used as a proof of concept for additional injection wells. The treatment SOR was looking to increase water injected into the well by a range of twenty to fifty percent. This would equate to an injectivity index (II) multiplier of 1.2 to 1.7. Post stimulation total water injection rates into both zones increased by over one hundred and ninety five percent. This increase is ~2.7 higher than the estimated rate. The outcome shows the potential of this type of stimulation technique. Novel/Additive Information The uniqueness of this project lies in the fact that the injector well was stimulated via LWI utilizing a combination of an HF acid treatment and a High Viscosity ReFrac. This combination treatment produced an increase in zonal contribution which translated into higher seawater injection rates that allowed better reservoir voidage replacement in the field.