| 主权项 |
1. A method of measuring and correctly attributing fluid, geochemical and geomechanical properties to individual coal seams in a well penetrating multiple seams, comprising the steps of:
(a) deploying a test string, comprising a straddle packer assembly at least one valve assembly and two pressure gauges positioned at different heights above the valve assembly, into a well on a work string; (b) positioning the straddle packer across a coal seam and setting the packers to isolate that coal seam from the remainder of the wellbore and other coal seams in the well; (c) opening a valve above the straddle packer assembly to allow fluid to flow from the coal seam into the work string; (d) monitoring of fluid flow rates and pressures at the coal seam during the flow period; (e) closing the valve above the straddle packer assembly and monitoring pressure at the coal seam during the build-up period; (f) filling the test string with water to surface, move the valve above the straddle packer assembly to the circulation position; (g) displacing the fluid in the work string under pressure to surface; (h) diverting the fluid through a choke manifold at surface applying sufficient back pressure to keep gasses dissolved in the fluid, while simultaneously monitoring fluid properties entering the choke manifold; (i) pumping air or nitrogen down the work string to lower the water level. (j) moving the valve above the straddle packer assembly back to the closed position before any nitrogen enters the annulus; and (k) continue withdrawing fluid from the coal seam into the work string above the straddle packer until the monitored fluid properties, including dissolved methane content, reach a steady state condition, where this condition indicates that the fluid is representative of authentic reservoir fluid in the coal seam. |
