Method of reducing formation damage when drilling for oil and gas
| Title: | Method of reducing formation damage when drilling for oil and gas |
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| Patent Number: | 5,877,126 |
| Publication Date: | March 02, 1999 |
| Appl. No: | 08/893,048 |
| Application Filed: | July 14, 1997 |
| Abstract: | A method of reducing formation damage when drilling for oil and gas. Firstly, determining initial water, hydrocarbon and gas saturation in the porous formation under consideration. Secondly, determining a preferential wettability of the porous formation. Thirdly, determining potential damaging effects due to aqueous phase trapping as a result of increasing water saturation in the porous formation. Fourthly, determining an alcohol type and concentration that will reduce severity of aqueous phase trapping. Fifthly, incorporating the alcohol type and concentration into a drilling fluid. The alcohol concentration will not less than 1% of the volume of the drilling fluid. Sixthly, pumping the drilling fluid containing the alcohol down a drilling string to a drill bit during drilling operations. The described method reduces invasive damage caused by drilling fluid entering the formation. |
| Inventors: | Masikewich, James Darrell (Calgary, CAX); Churcher, Peter Lawrence (North Richland Hills, TX); Bennion, Douglas Brant (Calgary, CAX) |
| Assignees: | Q'Max Solutions Inc. (Calgary, CAX) |
| Claim: | The embodiment of the invention in which an exclusive property or privilege is claimed are defined as follows |
| Claim: | 1. A method of reducing formation damage when drilling for oil and gas, comprising the steps of |
| Claim: | determining initial water, hydrocarbon and gas saturation in a formation under consideration; |
| Claim: | boring a well through the formation with a drill string; and |
| Claim: | pumping a drilling fluid containing alcohol into the well while boring with the drill string, wherein the alcohol is (A) water soluble when the formation is predominantly water saturated, (B) water insoluble when the formation is predominantly oil saturated and (C) an equal mixture of a water soluble alcohol and a water insoluble alcohol when the formation is saturated equally with water and oil. |
| Claim: | 2. The method as defined in claim 1, in which the alcohol is present in an amount at least 1% by weight of the drilling fluid. |
| Claim: | 3. The method as defined in claim 1, in which the alcohol is present in an amount at least 4% by weight of the drilling fluid. |
| Current U.S. Class: | 507/139; 507/266 |
| Current International Class: | C09K 700; C09K 702 |
| Patent References Cited: | 4064055 December 1977 Carney 4409108 October 1983 Carney et al. 5008026 April 1991 Gardner et al. 5152907 October 1992 Dulaney et al. 5361841 November 1994 Hale et al. 5361842 November 1994 Hale et al. 5436227 July 1995 Hale et al. |
| Other References: | Reductions in the Productivity of Oil & Gas Reservoirs due to Aqueous Phase Trapping by D. Brant Bennion, Mauro F. Cimolal, Ronald F. Bletz, F. Brent Thomas, Petroleum Society of CIM, Paper No. CIM 93-24, p1-10 (13 pages in total with figures and tables), May 1993. Properly designed underbalanced drilling fluids can limit formation damages, P. L. Churcher, Fred J. Yurkiw, Ron F. Bietz, D. Brant Bennion, Oil and Gas Journal, Apr. 29, 1996, pp. 50-55. Underbalanced Drilling, Praises and Perils, D. Brant Bennion, F. Brent Thomas, Ronald F. Bietz and Douglas G. Bennion, SPE 35242, paper presented at SPE Permian Basin Oil and Gas Recovery Conference, Mar., 1996, Midland Texas, 13 pages. |
| Primary Examiner: | Tucker, Philip |
| Attorney, Agent or Firm: | Lambert, Anthony R. |
| Accession Number: | edspgr.05877126 |
| Database: | USPTO Patent Grants |
| Language: | English |
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