【系列专题】页岩油的创新时代：生产回忆录（2）

NEW COATING APPLICATION ENHANCES SILICA DUST CONTROL

Silica dust emissions from hydraulic fracturing remain an ongoing concern for the industry. A collaborated with industry experts, applied 50-plus years of coating expertise and adapted a coating application system to develop an effective technology for silica dust control. SandTec, A patented next-generation silica dust control proppant coating technology, reduces respirable silica dust by up to 99% to within the Occupational Safety and Health Administration’s new permissible exposure limit and action level. When applied to fracture sand, SandTec provides continuous silica dust protection across the hydraulic fracturing supply chain. The technology provides continuous protection from sand plant to wellhead, and it simplifies and fast-tracks fracture sand logistics. SandTec also offers ease of application without drying or curing and compatibility with a variety of fracture fluids while not adversely affecting well performance or occupying valuable fracture site real estate. With this technology there is no need for setup, tear-down or maintenance of mechanical dust control systems. SandTec offers reduction of site dust that can adversely affect equipment, and it is an environmentally friendly U.S. Department of Agriculture-certified 100% biobased product under the BioPreferred program.

NEW CEMENT SYSTEM OFFERS ENHANCED MECHANICAL PROPERTIES, LOWER DENSITY

N cement is a low-Portland cement system designed to deliver better mechanical properties at a lower density than conventional cement systems. This technology is the result of D’s R&D team discovering physicochemical synergies between specialized materials and Portland cement. The improved mechanical properties can include increased ductility for better resistance to cyclical stress loading during fracturing stages; increased “strain to failure,” improving robustness for the life of the well; and improved compressive and tensile strengths at given density. N cement has demonstrated more than 10% improvement in compressive strength and up to a 15% improvement in elasticity compared to a conventional cement system with greater than a 1-parts-per-gallon higher density. This combination of enhancements results in a compressive strength to Young’s modulus ratio that can be 30% higher than the higher density conventional cement systems. N cement enables lighter weight cement systems with easier and improved mechanical properties without increasing cost to the customer or requiring additional rigsite equipment. This new product was commercially introduced in early 2016, and to date more than 1 MMbbl have been pumped for more than 90 customers.

NEW BIODEGRADABLE FRACTURING SLEEVE BALLS, PLUGS DISSOLVE FASTER

Operators have struggled with biodegradable frack sleeve balls and plugs as they can take several days or weeks to dissolve. L Solutions LLC has developed a microbial solution that dissolves polyactic acid polymer and dissolvable packers much more quickly—in hours rather than days—at a wide range of temperatures. This allows much quicker production ramps and revenue generation. L also is working on hydraulic fracturing/ completion solutions such as in situ biosurfactant production, fracture damage repair and biopolymer utilization for carrier fluids. These solutions support the trend toward increasing lateral lengths that are otherwise constrained by coiled tubing limitations (see figure). For example, L’ biodegradable biosurfactant flowback solution can efficiently decrease water surface tension to the desired 28 to 30 dynes/ cm range.

DISSOLVABLE ALLOYS OFFER FLEXIBILITY IN SLIDING SLEEVE, PNP OPERATIONS

M offers S dissolving magnesium alloys, which encompass a wide range of material properties for highstrength or high-ductility applications as well as controlled dissolution performance in salt solutions or freshwater. S alloys are being used in sliding sleeve and plug-and-perf (PNP) applications as fracturing balls and for dissolving fracturing plug components in North American oil and gas wells. The wide range of SoluMag dissolving magnesium alloys was developed to give the designer, service company or operator the confidence that the material will work in downhole conditions predictably and reliably. Using S lowers the risk of uncorroded magnesium returning to surface. Giving the user the data as to how this material performs in the wide range of operating conditions will allow the completion to go smoothly without intervention.

NEW RESIN OFFERS MORE THAN 20,000 PSI OF STRENGTH

M, a producer of high-performance polymers, offers a new nonmetallic composite material for inner-string cementing equipment. P is a new high-strength grade of thermosetting resin for replacing aluminum in plugs, valves, noses and housings. The product offers more than 20,000 psi of strength as well as temperature ratings that exceed 204 C (400 F). The material is easy to machine and drills out up to 20 times faster than aluminum, delivering several hours of rig time cost savings. Like the other products in M’s P product line, P is easy to mold using low-cost equipment in high throughput. The new high-strength grade of thermosetting resin complements M’s product line of low drag and wear-resistant polymers.

SOLID OST ENHANCES PRODUCTION ANALYSIS

The utility of oil-soluble tracers (OST) in production analysis is based on the assumption that chemical tracer recovery in produced oil accurately reflects downhole oil production. How closely this holds true is a function of how closely OST recovery is proportional to actual oil production. Any fluid pressure pumped into a formation can be squeezed back out of the formation by in situ pressure and can result in false-positive oil production readings. Historical data recovery from liquid OSTs has been relatively short-term. This is because injected OST liquid volumes are low relative to total injected fracture fluid volumes and consequently quickly play out. This has been a well-known and generally accepted industry norm for decades, with no known practical alternative. To address these limitations, 34 solid OST products are now available to the completion and refracturing market. These solid particulate OSTs are injected into the blender tub along with the proppant and carried out into the formation during hydraulic fracturing. These particulates then remain locked deeply in situ in the fracture pack, thereby eliminating the effect of formation pressure squeezing the OSTs back out of the formation as the fracture pressure wave subsides. The particulate OST only releases its chemical tracer signature when movable oil comes in contact with the embedded particulate. This results in longer term datasets, with some instances exceeding two years of tracer recovery.