Combining Matrix Stimulation and Gravel Packing Using a Non-acid Based Fluid

Armirola, Fernando; Machacon, Moises; Pinto, C.; Milne, Arthur William; Lastre, Manuel; Miquilena, Emilio

doi:10.2118/143788-ms

Cited by 11 publications

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

High-Temperature Laboratory Testing of Illitic Sandstone Outcrop Cores With HCl-Alternative Fluids

Mahmoud

Nasr‐El‐Din

Wolf

2014

SPE Production &Amp; Operations

View full text Add to dashboard Cite

Summary Illitic sandstone reservoirs are sensitive to hydrochloric-acid (HCl) -based fluids. When HCl contacts illite, it breaks down and causes fines migration and formation damage. The migration of fines through the porous media will block the pores, reduce permeability, and decrease the production rate of oil and gas wells. A thorough literature review showed that all clay minerals are essentially unstable in HCl at temperatures greater than 300°F. In turn, there is a need to search for stimulation fluids other than HCl to stimulate deep sandstone reservoirs. Alternative fluids to HCl/hydrofluoric (HF) mud acids were introduced to stimulate and remove the damage from illitic sandstone reservoirs. These fluids are chelating agents such as hydroxyl ethylene diaminetriacetic acid (HEDTA) and glutamic acid-N,N-diacetic acid (GLDA). In this study, sandstone cores with different illite contents were examined. Illite contents of 1, 10, 14, and 18 wt% of the sandstone cores were used in the coreflood experiments at 300°F. Different combinations of GLDA/HF were tested to determine the optimum ratio of chelate/HF. Computed tomography scans and permeability measurements before and after the treatment were used to assess the effectiveness of each fluid in removing the damage and in the stimulation of the sandstone cores. The results show that 15 wt% HCl caused severe damage to sandstone cores with different illite contents. GLDA and HEDTA solutions showed a good compatibility with the illitic sandstone cores, with up to 18 wt% at 300°F. Permeability measurements showed that GLDA performed better than HEDTA at a pH of 4 and at the same molar concentration. The optimum ratio of GLDA/HF concentration was found to be 20 wt% GLDA/1 wt% HF, which gives the maximum increase in core permeability. No deconsolidation was noted with the two chelates tested. The results obtained from this study will significantly improve the outcome of acid treatments in illitic sandstone reservoirs at high temperatures.

show abstract

High-Temperature Laboratory Testing of Illitic Sandstone Outcrop Cores With HCl-Alternative Fluids

Mahmoud

Nasr‐El‐Din

Wolf

2014

SPE Production &Amp; Operations

View full text Add to dashboard Cite

show abstract

Stimulation in Wells with Electric Submergible Pumps Increases Production and Save Costs without Damaging Pumps

Gallegos

Ordonez

Milne

et al. 2012

SPE Latin America and Caribbean Petroleum Engineering Conference

View full text Add to dashboard Cite

Stimulating sandstone formations typically requires a mixture of hydrochloric acid (HCl) and hydrofluoric acid (HF) to dissolve formation damaging minerals. The HF reacts with and dissolves all HCl soluble minerals and, dissolves or partially dissolves siliceous materials such as bentonite and naturally occurring formation clays. Because these acid treatments are corrosive, it is common practice in low-pressure wells to pull out the electrical submersible pumps (ESPs) prior to performing a stimulation treatment to prevent damage to them. Doing so results in additional costs and deferred production.In Ecuador, oil is produced from low-pressure sandstone reservoirs by using ESPs. In many of these reservoirs production is limited by scaling or fines migration. The low reservoir pressure often results in additional formation damage when during workovers because of the loss of completion fluid, emulsions, and clay instability. Many operators prefer to produce well with formation damage rather than expose the ESPs to corrosive fluids to remove the damage or generate additionally damage during a workover.Using a non-acid chelating system (NACS) as the stimulation fluid combined with a placement technique made it possible to stimulate wells completed with ESPs or with corrosion sensitive completions, without needing to pull out the ESP for the stimulation treatment.A laboratory study to assess the corrosion of each component of an ESP exposed to different treating fluids (live and spent) for extended periods was undertaken. The NACS fluid was capable of both removing calcium scales and fines, and preventing fines migration while minimizng corrsoion.The NACS stimulation fluid successfully treated more than 10 wells competed with ESPs. In many cases, production in these wells increased by 35%. In addition, the treatment cost was 70% less than treatments for which a workover rig was used. Moreover, deferred production was reduced from days to hours.Because of the time and cost savings, this technique should be particularly beneficial in marginal fields, where rig availability and economics are often an issue.

show abstract

Field Treatment to Stimulate an Oil Well in an Offshore Sandstone Reservoir Using a Novel, Low Corrosive, Environmentally Friendly Fluid

Nasr‐El‐Din

Dana²,

Tomos³

et al. 2014

SPE International Symposium and Exhibition on Formation Damage Control

View full text Add to dashboard Cite

Acidizing in sandstone formations is a real challenge for the industry. Fines migration, sand production, and additional damages due to precipitation are some of the common concerns with sandstone treatments. Furthermore, the complexities of sandstone formations require a mixture of acids and loadings of many additives. The environmentally friendly chelating agent, glutamic acid N,N-diacetic acid, GLDA, was successfully used to stimulate deep gas wells in carbonate reservoirs. It was extensively tested in the lab to stimulate sandstone cores with various mineralogies. Significant permeability improvements were reported in our previous papers over a wide range of conditions. In this paper, we evaluate the results of the first field application with a fluid based on this chelating agent to acidize an offshore, sour oil well in a sandstone reservoir. The field treatment included pumping a preflush of xylene to remove oil residues and any possible asphaltene deposited in the wellbore area, followed by the main stage that contained 25 wt% GLDA, a corrosion inhibitor, and a water wetting surfactant. The treatment fluids were displaced into the formation by pumping diesel. Following the treatment, the treatment fluids were allowed to soak for 6 hours, then the well was put on production, and samples of flowback fluids were collected. The concentrations of key cations were determined using ICP, and the chelate concentration was measured utilizing a titration method using ferric chloride solutions. Corrosion tests conducted on low carbon steel tubulars indicated that this chelate has low corrosion rates under bottomhole conditions. No inhibitor intensifier was needed. The treatment was applied in the field without encountering any operational problems. A significant gain in oil production was achieved without adversely impacting the water cut, causing sand production, or fines migration. Analysis of flowback samples confirmed the ability of the chelating agent solution to dissolve various types of carbonates, oxides, and sulfides, while keeping the dissolved species in solution without causing unwanted precipitation. Unlike previous treatments conducted on this well, where 15 wt% HCl or 13.5/1.5 HCL/HF acids were used, the concentrations of iron and manganese in the flowback samples were negligible, confirming the very low corrosion rates of well tubulars when using GLDA solutions.

show abstract

Combining Matrix Stimulation and Gravel Packing Using a Non-acid Based Fluid

Cited by 11 publications

References 20 publications

High-Temperature Laboratory Testing of Illitic Sandstone Outcrop Cores With HCl-Alternative Fluids

High-Temperature Laboratory Testing of Illitic Sandstone Outcrop Cores With HCl-Alternative Fluids

Stimulation in Wells with Electric Submergible Pumps Increases Production and Save Costs without Damaging Pumps

Field Treatment to Stimulate an Oil Well in an Offshore Sandstone Reservoir Using a Novel, Low Corrosive, Environmentally Friendly Fluid

Contact Info

Product

Resources

About