Reservoir quality of available reservoirs in the US is decreasing and the nature in which wells are produced today is much more aggressive than years past, resulting in increased damage to fracture conductivity which reduces gas flow rates. Earlier findings recently confirmed by an independent research facility, coupled with recently completed studies of long-term production results have shown that in addition to reservoir depletion, two additional factors accelerate production decline following propped stimulation treatments. These factors are invasion of crushed formation grains into the proppant pack, and loss of fracture width due to proppant embedment and flowback.
The findings and studies also show that these negative effects can be mitigated by designing treatments and choosing propping material based on enhanced reservoir understanding, and applying the appropriate coating to the propping agents used in the stimulation treatments. Only Halliburton offers the proppant coating technologies that incorporate SandWedge and Expedite agents.
"While we can not affect the reservoir quality, our conductivity endurance technologies address getting more conductivity from the proppant placed at first gas and throughout the well's productive lifetime, allowing for increased flow," said Jim Prestidge, vice president, Halliburton's Production Optimization Division. "In fact, an important consideration is that during this period of restricted proppant availability, we can achieve the conductivity needed but use up to 30 percent less proppant. We believe that these technologies will change the manner in which the industry approaches fracture stimulation in the future in both high perm and low perm reservoirs."
Halliburton's SandWedge conductivity enhancement system attacks two significant problems that result in fracture conductivity loss: formation fine intrusion into the proppant pack and proppant pack damage resulting from production stress cycling. The unique characteristics of SandWedge agent reduce or eliminate intrusion of formation material into the proppant pack and stabilize the proppant pack which increases its resistance to stress cycling damage that can occur when wells are shut-in for service.
The system works by chemically modifying the surface of the proppant grains to enhance fracture conductivity resulting from treatments using water-based fluids. The coating process allows the system to be used on any available proppant and it is compatible with all Halliburton water-based fracturing fluids. Also, since this coating is performed in real time at the well site, only the material pumped into the well is coated.
In addition, the SandWedge enhancer is specially designed to allow overboard discharge in the Gulf of Mexico. It conforms to all overboard oil and grease limits set by the U.S. Minerals Management Service and can be used in coalbed methane wells and other environmentally sensitive land areas.
In reservoirs of 60 ° to 550 ° Fahrenheit where controlling proppant flowback is a primary concern, Halliburton's Expedite service can improve proppant flowback control, enhance conductivity and reduce time to production, thereby improving the net present value (NPV) of fracturing treatments. Expedite service provides the highest compressive strength available, which is critical to effectively controlling proppant flowback and allowing operators to optimally produce their wells.
Widely used (precoated) resin-coated proppants often cannot provide the necessary compressive strength because high closure stress is required to provide good grain-to-grain contact prior to resin curing. This requirement can lead to proppant flowback since in many formations the fracture may not close sufficiently during the first 24 hours after treatments. However, even with no closure stress, proppant coated using Expedite service can provide high strength, consolidated proppant packs. These packs can reduce proppant flowback under the most severe conditions and sustain exceptionally high production rates.
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