Patent CA-2392831-A1 (CA)
Inventor: DAS ASHIS KUMAR
IPC: E21B43/16
Filed: 2002-07-17
Abstract: The above titled invention purports to use of vertical flooding technique instead of horizontal flooding technique along with some improvisations not earlier recognized in oil industry as mentioned above in the background. Only a few operations worldwide are/have been in vogue that used the concepts of vertical flood or gravity stable or toe-to-heal displacement operation. Some earlier works are cited in following US patents granted already as shown in Table 1. However, all of these as well as all previous oil recovery methods were devoid of following main features that are highlights of current "believed-to-be-future-panacea-technology" in oil industry:   (a) water flood devoid from primary recovery to end (for new field or pools) (b) simple draining concept from primary recovery stage to make viscous fingering or cross flow minimum (c) a much new improved heating concept with some new Physics of thermal /electrical/ electromagnetic heating with a potential gradient or spatially distributed thermal/electrical /electromagnetic potential gradient along the spans of multilaterals that is believed to be capable of generating a much more intense heating due to additional heat flow or current flow paths than normally possible by current technique. (d) A miscibility generation method with only nitrogen (or carbon dioxide, if nitrogen is not economic) as this is only non-reactive miscibility generating fluid among others and freely available and allows complete sweep to final high pressure nitrogen gas left as stored subsidence preventing reservoir pore space fluid than water with a lot of residual oil in current operations worldwide. An additive to lower minimum miscibility pressure of nitrogen will also be required that will call for search of such chemical in laboratory. One such chemical (as in recycle operation available) is methane gas, as a boon in disguise, in the process methodology suggested (feature 'e' below). (e) A gas recycling from beginning right from primary recovery stage with methane separated from production stream and recycled as injection stream in gradually decreasing percentage of methane and increasing percentage of mixed nitrogen (or carbon dioxide) gas as the case may be.        Table 1: US Patents granted already on vertical flooding subject US Patent Number(s)    Grant Date   Patentee(s)     US class number 4088190              May, 1978   Fisher et al     166/403 4344485              Aug.,1982   Butler              166/271 4501326              Feb.,1985   Edmunds             166/272 4598770              Jul.,1986   Shu et al           166/245 4682652              Jul.,1987   Huang et al         166/263 4696345              Sep.,1987   Hsueh               166/245 4889186              Dec.,1989   Hanson et al        166/252 5016710 May, 1991   Renard et al        166/245 5054551              Oct.,1991   Duersken            166/272 5065821              Nov.,1991   Huang et al         166/245 5520247              May.,1966   Gmelig et al        166/245 5607016     Mar.,1997   Butler              166/263 5626191              May, 1997   Greaves et al       166/245 6167966              Jan.,2001   Ayasse et al        166/268 It is believed that the total process that requires some affirmative calculations of heating rate improvement and miscibility efficiency as well as productivity index of multilateral drilling design (with minimized cross flow effects of particle flow due to heat and fluid gradients) and overall case study economics of displacement improvement and drilling savings with break even time and project or field life improvement, will be presented in the examination stage of the patent granting as time available for doing it at this application filing stage to avail the priority is necessary immediately. Also the new Physics of heat rate improvement calculation is likely to take some time as such calculations have not been performed before in Physics of electrical or heat or electromagnetic heat engineering. An additional microwave application, devoid of usual steal pipe's low microwave absorption problems upgradable by any new material synthesis in the pipe design is also something that will take time to find. These will constitute the final total method description or specification.   In the basic application filed in India I proposed vertical flooding mainly because an earlier missing point that viscous fingering is minimum, and ratio of vertical to horizontal rate under similar pressure gradient magnitude is high despite adverse vertical to horizontal permeability ratio, as proved in an earlier published paper of mine (JCPT, January, 1999) that area of flow cross section can be used advantageously to achieve this fact. This and other features claimed in this patent application are all annexed in the appendix of this application to show prior segmented arts (not enabling the disclosure of the overall synthesized total process) in my past works. It is indicated which one of these is published and which one unpublished, among these.