Stimulation Techniques

In addition to hydraulic fracturing, there are other stimulation techniques such as acid fracturing or matrix stimulation. Hydraulic fracturing finds use not only in the stimulation of oil and gas reservoirs, but also in coal seams to stimulate the flow of methane from there. 

Fracturing fluids are often classified into water-based fluids, oil-based fluids, alcohol-based fluids, emulsion fluids, and foam-based fluids. 

Fracturing fluids are injected into a subterranean formation for the following purposes  

After the completion of the fracturing treatment, the fluid viscosity should decrease to allow the placement of the proppant and a rapid fluid return through the fracture. It is important to control the time at which the viscosity break occurs. In addition, the degraded polymer should produce little residue to restrict the flow of fluids through the fracture. 

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Air and Gas. In the regions where air and natural gas are used as the principal drilling fluids, the potential oil and gas production zones usually have low pore pressure, or require well stimulation techniques to yield commercial production. In these production zones, air drilling (or natural gas drilling) is continued into the production zone and the initial produced formation fluids are carried to the surface by the circulating air or natural gas. This is nearly the same situation as in mud drilling, except that in air (or gas) drilling the transit time for the initial produced formation fluids to reach the surface is much shorter. In mud... 

External conditions can also cause a decrease in arousal that may also affect cognitive/psychomotor performance. An interesting stimulation study conducted by Suedfield and Eich136 showed how arousal can be reduced. They used Restricted Environmental Stimulation Technique (REST), in which a subject floats in a dense solution of skin temperature water and Epsom salts. This technique was shown to decrease subjective reports of arousal. Similar reports come from studies of meditation137-138 and systematic relaxation.139... 

King, G.E. Foam and Nitrified Fluid Treatments - Stimulation Techniques and More , SPE paper 14477, Distinguished Lecturer Program, 1985-86. 

Misak, M.D., et al. "Edwards Limestone Completions Improved by New Stimulation Technique," SPE paper 7115, 1978 Southwest Texas Regional SPE Meeting, Corpus Christi, April 14. 

Braun and Scott (1987) used two-photon ionization of benzene and azulene in n-hexane and followed the e-ion recombination process by monitoring the transient absorption of the electron. The results are not very different from those obtained by the IR stimulation technique. A mean thermalization length of 5.0 nm was inferred at 223 K using a two-photon excitation at 266 nm. Hong and Noolandi s theory was used for the analysis. The absorption technique was... 

Near-well treatments, in which chemicals are injected into producing and sometimes injector wells, where they are intended to react with the reservoir rock. Well stimulation techniques such as acidization, for example, are intended to increase the formation s permeability. Alternatively, producing wells may receive squeeze treatments in which a mineral scale inhibitor is injected into the formation. In this case, the treatment is designed so that the inhibitor sorbs onto mineral surfaces, where it can gradually desorb into the formation water during production. 

The production of tight gas is technically very demanding. The major differences from conventional production arise because of the poor permeability of tight reservoirs, where the natural gas cannot flow as quickly to the well or in sufficient volumes to be economic, and where production rates are usually quite low. The principal prerequisite for economically producing tight gas is, therefore, to improve reservoir permeability, e.g., by artificial stimulation techniques, such as hydraulic fracturing (i.e., the generation of artificial fracture systems). 

Lepore, Marino. 1993. "A Behavioral and Neurological Analysis of the Self-Administration of Brain-Stimulation Technique A Model of Drug Self-Administration." Ph.D. diss., McGill University. 

Koscielniak-Nielsen ZJ, Nielsen PR, Nielsen SL, Gardi T, Hermann C. Comparison of transarterial and multiple nerve stimulation techniques for axUlaiy block using a high dose of mepivacaine with adrenaline. Acta Anaesthesiol Scand 1999 43(4) 398-404. 

Coughing is a common physiological method to clear the respiratory passages. If it becomes uncontrolled, then medication often can help. Such medications are called antitussives. The cough control center has been located in the medulla of the brain by electrical stimulation techniques. Normally, coughing is caused by chemical or mechanical irritation of the respiratory tract. Therefore, to stop a cough, the source of the respiratory tract irritation should be eliminated and the signal to the medulla interrupted. 

King, G. E. Foam and Nitrified Fluid Treatments Stimulation Techniques Distinguished Lecture Program Society of Petroleum Engineers Richardson, TX, 1985 paper SPE 14477. 

The experiments conducted so far at the site in range of depths between 3000 and 3800 m show that hydraulic stimulation techniques can considerably increase the permeability in a rock volume that can extend up to several hundred meters around the well, thereby serving to establish connections between the wells. The major impact of the hydraulic stimulation could be explained by hydromechanical mechanisms (ruptures in fracture planes). However in the near well at the scale of some meters, a decrease of the impedancy is outlined via hydraulic vibration tests and is presently not well understood. As at this scale, the hydromechanical effect cannot be dissociated from the thermal effect due to the injection of a cold water in a hot media, the thermo-hydro-mechanical responses of the stimulated fractures must be investigated. 

The data discussed above indicate that during the primary production from the Zybza field, the application of the customary stimulation techniques based on geological characteristics of the reservoir, as a rule, failed to increase the rate of petroleum extraction and the oil recovery factor. History of oil production at the Zybza field showed that only the reservoir sections of macroporosity type were effectively exploited. The reservoir rocks of microporosity type did not yield their petroleum in spite of the application of the then known and proven methods of reservoir stimulation. 

In cocultures of fetal neurons from ventral half of the spinal cord (VH neurons) and from the dorsal root ganglion (DRG neurons) the synaptic transmission between pairs of spinal cord neurons from ventral half of the spinal cord (VH-VH connections) or between DRG neurons and VH neurons (DGR and VH connections) were studied with two cell recording and stimulation techniques. In 70% of the VH-VH connections and in 50% of the DGR-VH connections, Bay K 8644 failed to affect transmitter release. co-Conotoxin GVIA produced no consistent effect on EPSPs or IPSPs elicited by VH neurons by stimulation of the nearby neurons. VH EPSPs elicited by stimulation of the nearby DGR neurons were reduced by 50% by co-couotoxiu GVIA. Therefore, ueither sustaiued nor inactivating HVA Ca channels sensitive to Bay K 8644 or co-conotoxin GVIA such as those measured in the neuronal cell body are responsible for action-potential-evoked transmitter release from the majority of the VH neurons these channels may be involved in transmitter release in approximately 30% of these neurons [152]. 

With the development of fluorescence upconversion techniques, which nowadays provide femtosecond time resolution, it is also possible to directly measure the time evolution of the spontaneous emission following the excitation of the sample by the pirnip pulse. In this method, the fluorescence is collected and focused onto a nonlinear crystal, where it is superposed with the probe beam in order to perform upconversion. Time resolution is achieved because the probe pulse creates a time gate for the spontaneous emission, i.e. the fluorescence is only measured within the duration of the probe. Frequency resolution is achieved by subsequently dispersing the upconverted signal in a monochromator. Although fluorescence detection provides less photon yield than stimulated techniques, it has the desirable feature to exclusively monitor the time evolution in the initially excited electronic states (cf. the discussion above). 

It is difficult to compare the absolute sensitivities of the pheromone cells of bark beetles and moths on the basis of available experimental results, because different stimulation techniques have been used, and because the two classes of compounds have different vapor pressures. However, with cartridge-techniques,... 

Nervous system In a retrospective study to analyse the incidence of peripheral neuropathy in 157 patients with continuous sciatic nerve block in the popliteal fossa, three patients with an associated common superficial peroneal and sural nerve injury were identified via clinical and electromyographical studies [21 ]. In 44% percent of the patients US guidance was combined with a nerve stimulator technique. The authors conclude that methodological bias or technical problems (lateral vs posterior approach, US guidance) may account for the higher (1.9%) than average (0-0.5%) rate of peripheral neuropathy. It is of note that anatomically the common superficial peroneal and sural nerves were more affected than the tibial nerve, possibly due to their superficial location. 

Acidizing predates hydraulic fracturing and all other well stimulation techniques. HydrauHc fracturing was not discovered until the 1940s and was not commerciahzed until later. Acidizing is certainly also the oldest stimulation technique still in modern use. The earUest acid treatments of oil wells occurred as far back as 1895. The Standard Oil Company used concentrated hydrochloric add (HCl) to stimulate oil wells producing from carbonate formations in Lima, Ohio, at their Solar Refinery. 

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