A major processing step when treating gas is the removal of components such as heavy hydrocarbons or water. This is done either to recover saleable liquids or prevent hindsance during gas transportation (e.g. hydrate formation or two-phase flow). The Vortex tube device provides a novel and useful addition to the range of equipment available for this application. Vortex tube equipment has been used for improved separation in comparison with a Joule-Thomson system, without entering into the cost and complexity of a true is entropic system such as a turbo-expander unit. The relative advantage of the vortex tube is dependent upon the inlet conditions of the gas and available pressure drop. An optimum pressure drop of 25 - 35 % of the inlet gas pressure has been confirmed in practice. It is expected that future applications of vortex tube units will be concentrated where performance improvements over Joule-Thomson units, at low capital cost, are required. P. 471
Electrical downhole heating has been used for many years for flow assurance and now is being adapted for reservoir stimulation, viscosity reduction and "in situ" conversion of heavy oil. This paper starts with a short review of flow assurance applications in Alaska and Canada as described in SPE-165323-MS. It then reviews the current and developing technology and some of the heat transfer parameters for use of high voltage high power electrical heaters in a number of types of applications. In the past heater voltages have been limited to below 600 volts for mineral insulated cable heaters. Significant material and processing advances have now permitted operation at 4160 volts. This has a number of operational advantages in providing longer length heater capabilities and less parasitic heating loss in the overburden. MI cable production technology is now available to fabricate MI cable heaters that can produce 1600 meters lengths without external splices. The thermal heat transfer from the well casing to the reservoir is usually the limiting factor on the amount of energy that can be transferred from the electrical heater to the formation. Both constant power and constant temperature heaters are explained with the emphasis on in operation reliability of each type of heater. The paper concludes with an economic analysis of the opportunity provided by a high voltage MI cable heater system in a horizontal well.
Electrical heaters are being used in numerous down-hole applications including flow assurance, viscosity reduction, steam replacement (Cyclic Steam Stimulation and Steam Assisted Gravity Drainage) and a process called Insitu Conversion Process (ICP). These applications are described in SPE-165323-MS and SPE-170146-MS. Historically the heater has been attached to a pipe string with clamps. This has proven the technology works on short lengths but is labor intensive at the well site and not suitable for commercial application. This paper will describe an alternative method using coiled tubing for electrical heater deployment.Historically, long high power, high temperature, Mineral Insulated (MI) Cable heaters (over 300 feet) had to be fabricated with splices that increased the diameter about three times at the location of the splice. Recently an improved ceramic material technology has allowed the heaters to operate at higher voltages. This allows an increase in total heater length and the ability to insert into coiled tubing. Along with the increase in voltage, a new fabrication technique allows Љspliceless heatersЉ to be manufactured in continuous lengths to over 10,000 feet. Given this new manufacturing technology, trials have been performed to place the heater and instrumentation in coiled tubing and deployed with conventional coiled tubing technology.This paper reviews the improvements in the heater technology that allows spliceless fabrication and medium voltage operation. A review of initial deployment pilots is presented including a 2000 foot heated section installation by Shell in the Grosmont reservoir in Alberta Canada. The initial insertion of the heater in coiled tubing was done on an airstrip in Texas and then the coiled tubing was transported to Alberta Canada for deployment. Numerous pictures and installation caveats are included in the paper.This system of using coiled tubing for deployment has taken much of the labor from the well site to an off-site manufacturing location, reducing cost and streamlining the deployment at the well site. This process moves deployment of electrical heaters in downhole applications from a one-off pilot installation system to a commercially viable system with greatly improved economics and reliability. While the Grosmont installation used 4.5 inch coiled tubing, new heater designs make it possible to use 2.875 inch coiled tubing with the power and temperature characteristics necessary for technically functional application.
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