JAMES VAN BLARICUM
The next shock came in 1978-79 when the Iranian Revolution cut off oil production. Again, world oil prices raced up. Our most recent crisis was the Persian Gulf War. Iraq invaded Kuwait, and again, Americans worried about oil shortages and skyrocketing oil prices.
The U.S. has taken some steps to prevent another big oil crisis. For one thing, the U.S. has almost a three-month supply of oil tucked away in the Strategic Petroleum Reserve (SPR). Established in 1975, the SPR is only to be tapped during an energy emergency. The SPR was first used in January 1991, during the Persian Gulf Crisis.
The United States has also turned to non-Arab and non-OPEC countries for oil imports. Today, we import much of our oil from Canada and Mexico. This is good for us because we have friendly relations with our neighbors, and because the oil doesn't have to be shipped so far. Still, the amount of oil that we can import from Canada and Mexico is limited. By law, Mexico can only export half the oil it produces to the United States.
Even with the SPR and friends in the right places, the United States is not out of the woods. We still buy more than half our imported oil from OPEC countries, 11 percent of which comes from volatile Arab OPEC countries.
JAMES VAN BLARICUM
Comparison to HCl The rapid reaction between HCl and carbonate limits the penetration of HCl into carbonate formations. It is unlikely that HCl will remove deep formation damage and HCl is not suitable for deep matrix acidizing. Arcasolve™ can penetrate deeply and is suitable for both applications. HCl is particularly corrosive to steel, aluminium or chromium plated equipment which are components of many pumps. Expensive corrosion inhibitors need to be used in these circumstances. This cost becomes very significant when treating formations at higher temperatures due to the requirement for higher doses of corrosion inhibitor. Corrosion inhibitors are not required with Arcasolve™. The toxicity of corrosion inhibitors presents problems when disposing of spent HCl based acidizing fluid.. Arcasolve™ presents minimal chemical safety/toxicity problems to well process operators and is recognized to be a "green" product. It is possible to use Arcasolve for drilling damage removal from horizontal wells by introducing Arcasolve™ through the drill string following drilling operations. Use of coiled tubing, commonly used to place HCl is not needed with Arcasolve™. There is no requirement for additives to be added to Arcasolve™ to retard the rate of reaction. In particular high viscosity additives are not required, which present problems in applications such as fracture acidizing. Clean up following Arcasolve™ treatments is straightforward.
JAMES VAN BLARICUM
Comparison to Emulsified HCl Emulsified HCl involves the use of both organic solvents and HCl. Both are hazardous before and after mixing . The emulsion may not give a good distribution of acid downhole. The use of certain organic solvents in gas and water injection wells may reduce the gas or water relative permeability and permanently reduce well production. The use of a water based acidizing system with good penetration would be preferred for such wells allowing much easier control over the wetting characteristics of the formation. Use of oil-external emulsified acids may be limited by the increased frictional resistance to flow of these fluids down well tubulars. Arcasolve™ is lower hazard and does not suffer from injectivity or wettability problems.
JAMES VAN BLARICUM
Comparison to Acetic Acid Although acetic acid reacts more slowly than HCl, the reaction is still sufficiently rapid to give the problems summarized in section 2. In contrast, generation of acetic acid in-situ using Arcasolve™ allows acid to be delivered much deeper into the formation and better placement of acid along extended well-bores. Arcasolve is therefore more effective, and offers a much higher degree of control of acidizing than acid formulations based on acetic acid or other organic acids.
JAMES VAN BLARICUM
Use of Arcasolve™ in Fracture Acidizing Although not originally designed as a fluid for acid fraccing, the opportunity for Arcasolve™ in this application could be very significant. The comparison indicates that Arcasolve™ may represent an ideal fracture acidizing fluid, able to penetrate long distances, etch fracture faces, increase the permeability of the matrix where the fluid enters the formation by diffusion, and remove any existing formation damage. In addition the low viscosity of the fluid means that maximum production rate should be attained quickly following the treatment. Because acid is produced over a period of several hours or longer, acid fraccing treatments using Arcasolve™ may need to be performed in a different way to existing acid fraccing treatments. Fractures would need to be held open for at least several hours and possibly up to a day. The pad fluid used in conventional treatments would probably not be needed - Arcasolve™ would be injected directly.
JAMES VAN BLARICUM
Stimulation of Natural Fracture Networks using Arcasolve™ Arcasolve™ may be used to effectively stimulate natural fracture networks. Deep penetration along fractures can be achieved before acid is produced. Laboratory evaluation to date has been positive. Field trials are currently being conducted in the Austin Chalk. Use of Arcasolve™ in Gel Breaking Gel breaking is another application for Arcasolve™ for which additional patents are granted or pending. Arcasolve™ can be incorporated into acid sensitive gel systems such as borate cross linked guar so as to produce a complete break within a specific, desired time frame. Very deep penetration of acid can be achieved if needed and the use of gels and surfactants, which might cause cleanup or wettability reversal problems is not needed. As well as treating carbonate formations Arcasolve™ can be used to remove deep carbonate scale from sandstones. Arcasolve™ comes very close to being the ideal system for matrix acidizing described in [2]. Depending on the pump rate, typically 90% or more of the acid is delivered after the fluid has been placed. Matrix treatments designed to give a 20% increase in production rate (formation assumed to be undamaged) have given up to 80% increases in production (San Andres Dolomite, Texas) indicating effective damage removal even in wells considered undamaged.
JAMES VAN BLARICUM
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