Protect and then Inject: Optimized Well Fluids Successfully Drill Depleted Reservoirs to Store Gas

Vickers, Stephen R.; Bruce, Stephen; Hutton, Alistair Paul; Nunzi, Paolo

doi:10.2118/144798-ms

Cited by 7 publications

(1 citation statement)

References 8 publications

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“…Significant advancements in OBM reservoir drill-in fluid design for OH completions have been made in recent years 4 ; however, in most operations, damage is still common. Other than poorly designed drill-in fluids, other major factors influencing the degree of residual damage from OBM include variations in reservoir quality, permeability, pore-size distribution, lithology, reservoir depletion and the complexity of the completion.…”

Section: Introductionmentioning

confidence: 99%

Using Microemulsion Technology to Remove Oil-based Mud in Wellbore Displacement and Remediation Applications

et al. 2012

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Formation damage is a by-product of the drilling, completion, and production process and can be attributed to many factors. In openhole (OH) and cased-hole (CH) wells, hydrocarbon flow may be impeded by various damaging mechanisms caused by drilling and completion fluids, in-situ emulsions, water block, organic deposition, and oily debris left downhole.Microemulsion fluids have been successfully developed to effectively resolve the persistent problem of near-wellbore damage. The physical-chemical properties of these microemulsion systems include high oil solubilization, high diffusion coefficients through porous media, and the reduction of interfacial tension between organic and aqueous phases to near zero, making them excellent candidates for removing formation damage. The chemistry of microemulsion fluids make these systems excellent choices for superior synthetic or oil-based mud (S/OBM) displacements in casing and for OBM filter cake cleanup in openhole completion applications. Formulations have also been developed for casedhole perforation applications as well as post-perforation remediation treatments to remove the formation damage around the perforation or fracture zones. This paper presents a technical overview of microemulsion technology and a review of the test protocol used to qualify treatment solution designs for S/OBM displacement/cleanup and removal of formation damage in openhole and casedhole wells. Challenges and results from numerous field applications are presented that demonstrate the efficiency of microemulsion fluids for removing S/OBM debris and filter cakes, reducing near-wellbore damage and improving well productivity.

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Section: Introductionmentioning

confidence: 99%

Using Microemulsion Technology to Remove Oil-based Mud in Wellbore Displacement and Remediation Applications

et al. 2012

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Well Clean-Up Using a Combined Thermochemical/Chelating Agent Fluids

Mahmoud

2019

Journal of Energy Resources Technology

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The well clean-up process involves the removal of impermeable filter cake from the formation face. This process is essential to allow the formation fluids to flow from the reservoir to the wellbore. Different types of drilling fluids such as oil- and water-based drilling fluids are used to drill oil and gas wells. These drilling fluids are weighted with different weighting materials such as bentonite, calcium carbonate, and barite. The filter cake that forms on the formation face consists mainly of the drilling fluid weighting materials (around 90%), and the rest is other additives such as polymers or oil in the case of oil-base drilling fluids. The process of filter cake removal is very complicated because it involves more than one stage due to the compatibility issues of the fluids used to remove the filter cake. Different formulations were used to remove different types of filter cake, but the problem with these methods is the removal efficiency or the compatibility. In this paper, a new method was developed to remove different types of filter cakes and to clean-up oil and gas wells after drilling operations. Thermochemical fluids that consist of two inert salts when mixed together will generate very high pressure and high temperature in addition to hot water and hot nitrogen. These fluids are sodium nitrate and ammonium chloride. The filter cake was formed using barite and calcite water- and oil-based drilling fluids at high pressure and high temperature. The removal process started by injecting 500 ml of the two salts and left for different time periods from 6 to 24 h. The results of this study showed that the newly developed method of thermochemical removed the filter cake after 6 h with a removal efficiency of 89 wt% for the barite filter cake in the water-based drilling fluid. The mechanisms of removal using the combined solution of thermochemical fluid and ethylenediamine tetra-acetic acid (EDTA) chelating agent were explained by the generation of a strong pressure pulse that disturbed the filter cake and the generation of the high temperature that enhanced the barite dissolution and polymer degradation. This solution for filter cake removal works for reservoir temperatures greater than 100 °C.

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New Insights into Surfactant System Designs to Increase Hydrocarbon Production

Sherbeny

Bakr

Quintero

et al. 2013

SPE Middle East Oil and Gas Show and Conference

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Drilling and completing reservoirs without inducing measureable skin damage is rare. Frequently, drilling fluids impact a reservoir's flow potential while drilling as the rock matrix is invaded by solids and chemicals designed to enhance drilling performance. Drilling fluid can also cause formation damage if they are not properly removed during the displacement phase. These solids can migrate to the perforating zone and cause damage. Completion fluid designs governed by density for well control also often contribute to skin damage. Hydrocarbon flow may be impeded by damage caused by residual drilling debris or incompatible completion and workover fluids, in-situ emulsions, water block, organic deposition, or oily residue. Specialized surfactant systems have been developed to remediate near-wellbore damage caused by drilling and completion fluids, and damage induced by failed remediation attempts. The properties of these treatment systems include their ability to solubilize oil and, due to a significant reduction in interfacial tension between the organic and aqueous phases, effectively diffuse through the damaged zone to free up flow-resistant obstructions. The inherent properties of these systems make them ideal for removing induced formation damage as well as an excellent option for displacing synthetic or oil-based mud (S/OBM) from casing prior to the completion phase. In open-hole (OH) completions, specialized surfactant designs have proven very effective in removing S/OBM filter cake damage. In cased-hole (CH) completions, they have demonstrated a high degree of efficiency to clean damaged perforations.This paper presents a technical overview of surfactant systems for OH and CH remediation operations. The testing to qualify these fluids for the removal of damage and field results are presented that show the efficacy of these specialized surfactant systems to remove damage caused by OBM filter cakes and other oily debris to improve hydrocarbon recovery while addressing the operational challenges associated with these jobs. Introduction Avoidance of formation damage is a major attention when planning fluid systems for reservoir drilling and completion projects. 1-3 From a fluids standpoint, special emphasis is placed on developing systems that impart minimal damage to the rock matrix and leave the wellbore as clean as possible. The three primary cleaning activities target: (1) casing displacement cleanout, (2) filter cake removal in OH completions that use sand control techniques and (3) the clean-out of perforation tunnels in the near-wellbore region.Major improvements in OBM reservoir drill-in fluid design for OH completions have been made in recent years 4 ; however, in most operations, damage still exists. Other than poorly designed drill-in fluids, other major factors influencing the degree of residual damage from OBM include variations in reservoir quality, permeability, pore-size distribution, lithology, reservoir depletion and the complexity of the completion.In conventional completions, such as in sta...

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Protect and then Inject: Optimized Well Fluids Successfully Drill Depleted Reservoirs to Store Gas

Cited by 7 publications

References 8 publications

Using Microemulsion Technology to Remove Oil-based Mud in Wellbore Displacement and Remediation Applications

Using Microemulsion Technology to Remove Oil-based Mud in Wellbore Displacement and Remediation Applications

Well Clean-Up Using a Combined Thermochemical/Chelating Agent Fluids

New Insights into Surfactant System Designs to Increase Hydrocarbon Production

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