There is inconclusive evidence for the effectiveness of cryotherapy for the treatment of exercised-induced muscle damage (EIMD). Small sample sizes and treatment applications that did not correspond to evidence-based practice are limitations in previous studies that may have contributed to these equivocal findings. The purpose of this study was to examine the effectiveness of daily multiple applications of ice on EIMD throughout the 72-hour recovery period, an icing protocol that more closely resembles current clinical practice. Thirty-three subjects were assigned to either the cryotherapy group (n = 23) or control group (n = 10). The EIMD was induced through repeated isokinetic eccentric contractions of the right hamstring muscle group. The experimental group received ice immediately after induction of EIMD and continued to ice thrice a day for 20 minutes throughout the 72 hours; the control group received no intervention. Isometric torque, hamstring length, pain, and biochemical markers (creatine kinase [CK], alanine aminotransferase, and aspartate aminotransferase [AST]) were assessed at baseline, 24, 48, and 72 hours. Both groups demonstrated a significant change (p < 0.05) in all dependent variables compared with that at baseline, but there was no difference between groups except for pain. The cryotherapy group had significantly (p = 0.048) less pain (3.0 ± 2.1 cm) compared with the control (5.35 ± 2.5 cm) at 48 hours. Although not statistically significant, the cryotherapy group had a greater range of motion and lower CK and AST means at 72 hours compared with that of the control group. Repeated applications of ice can decrease the pain associated with EIMD significantly at 48 hours post EIMD. Although the results may not be unique, the methodology in this study was distinctive in that we used a larger sample size and an icing protocol similar to current recommended treatment practice.

Achieving optimal fluid performance with biopolymer viscosifiers, xanthan and welan, depends on reaching or exceeding a minimum or critical polymer concentration (CPC). CPC is affected by a variety of fluid and wellbore conditions, including: temperature and salinity, average shear rate, shear history, velocity gradients, hole angle, polymer configuration and rigidity, and the size, density, and concentration of suspended solids. The suspension and transport properties of xanthan and welan correlate directly to low-shear-rate-viscosity (LSRV) and elasticity (G'), properties which cannot be quantified with a conventional field viscometer. LSRV and G' are qualitatively related to a polymer's molecular rigidity and configuration, and quantitatively to the number of physical and chemical polymer chain associations, referred to as polymer networks and structures.

SPE Members Abstract A laboratory study was conducted to substantiate the exceptional hole-cleaning performance of "rheology engineered", biopolymer-based mud systems used in Prudhoe Bay, Alaska, horizontal wells. The study focused on the impact of very-low-shear-rate viscosity and evaluated the combined effects of rheology, flow rate, velocity profile, eccentricity, pipe rotation, and inclination on hole-cleaning efficiency. The study confirmed that the rheological "fingerprints" of the biopolymer fluids provide optimum hole-cleaning and suspension. These benefits were attributed to the time-independent, yield-pseudoplastic behavior not obtainable with traditional viscosifiers. Engineering of the specially formulated biopolymer fluids represents a clear departure from conventional methods and field rheological concepts. Rheological properties of the drill-in fluids were simulated by solutions of clarified xanthan gum. The biopolymer fluids consistently out performed pseudoplastic, hydroxyethyl cellulose fluids tested for comparison. Hole-cleaning studies were run on two flow loops; measurements were taken on several types of rheometers to characterize the fluids. Videotape recordings documented the interaction and interdependence among the hole-cleaning parameters and allowed measurement of velocity profiles in tubes and annuli. Introduction Specially designed, biopolymer-based drill-in fluids play a key role in the success of Prudhoe Bay, Alaska, horizontal wells. Oil-based muds formulated with Arctic diesel were used in the early stages of the development program. However, safety, health, and environmental issues clearly were of concern. Furthermore, poor hole cleaning, difficulty running liners to bottom, high costs, and production facility complications were associated with use of the oil-based muds. Prudhoe Bay biopolymer fluids provide the proper balance among performance, cost, and environmental factors. In addition to being non-damaging and inhibitive, they exhibit optimal cuttings transport, suspension, and hydraulic characteristics. Their hole-cleaning capabilities and unique rheological properties are the focus of this paper. The biopolymer fluids are "rheology engineered" mud systems. P. 151^

SynopsisViscoelastic properties of the BBL ladder polymer were determined by a dynamic mechanical technique for the temperature range -150°C to 250°C and at frequencies of 3.5, 11, and 110 Hz. A secondary loss dispersion centered a t -50°C (at 110 Hz) was discovered which probably arises from an in-chain relaxation mechanism. The loss dispersion resembles @-transitions found in more conventional polymers in intensity (maximum tan 6 = 0.035), activation energy( E = 19,000 cal/mole), and in its close relation to the high-temperature mechanical properties of the polymers. Only slight changes in the low-temperature loss peak cause significant increases in brittleness. It is proposed that such changes, produced by a variety of environments, result from random chain scission a t imperfection p0int.s in the ladder structure. For this reason we conclude that improving the environmental stability of BBL is of prime importance in its further development for specific applications.

A clarified xanthan drilling fluid was designed in order to replace the arctic diesel based drilling fluid conventionally used to drill horizontal wells in Prudhoe Bay. Use of this fluid in conjunction with well design changes has resulted in reduced drilling costs and increased well productivity.The fluid is designed to exhibit a true yield stress, which in conjunction with pipe rotation improves hole cleaning in high angle holes. The fluid is also non-damaging, provides shale inhibition, and is environmentally safe.