Electricity: measuring and testing – Of geophysical surface or subsurface in situ – With radiant energy or nonconductive-type transmitter
Reexamination Certificate
1999-07-29
2001-10-09
Metjahic, Safet (Department: 2862)
Electricity: measuring and testing
Of geophysical surface or subsurface in situ
With radiant energy or nonconductive-type transmitter
C324S338000
Reexamination Certificate
active
06300762
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention concerns the use of polyaryletherketone-based thermoplastic materials in downhole logging applications. By way of background, downhole logging tools are exposed to difficult environmental conditions. The average depth of wells drilled each year becomes deeper and deeper, both on land and offshore. As the wells become deeper, the operating pressures and temperatures become higher. The open hole involves the drilling of a borehole through subsurface formations. After the drill bit has passed through each strata, it leaves a fairly rough, abrasive surface along the borehole wall. Wall spalling can also create sharp edges. While the abrasive nature is reduced by the accumulation of mud cake on the borehole wall, the repeated travel of a logging tool through the borehole still produces abrasive wear to the borehole wall. In addition, a deviated borehole will further lead to abrasive wear on the logging tools.
Drilled wells present an extremely hostile environment. Boreholes are often rugose and abrasive. Drilling muds, which are used to facilitate drilling, contain chemical additives that may degrade non-metallic materials. They are highly caustic with a pH ranging as high as 12.5. Other well fluids may include salt water, crude oil, carbon dioxide, and hydrogen sulfide, all of which are corrosive to many materials.
Downhole conditions progressively become more hostile at greater depths. At depths of 5,000 to 8,000 meters, bottom hole temperatures (BHT) of 260° C. and pressures of 170 Mpa are often encountered. This exacerbates degradation of exposed logging tool materials.
These deep well conditions of high pressure and high temperature (hereinafter, “HPHT”) damage the external or exposed logging tool components. Internal electronics need to be protected from heat and external housing need to be upgraded. The most vulnerable materials are the plastic and composite materials that are exposed to caustic drilling mud and other corrosive borehole fluids. Some tools, such as those making electrical induction, resistivity, and magnetic resonance measurements, require these non-conductive, non-magnetic materials of construction in order to function properly. This requires materials that are essentially transparent to electromagnetic radiation and have a magnetic permeability of one.
Ceramics generally are too brittle, i.e., a sharp impact may fracture the ceramic. Conventional plastics, such as epoxies and phenolics, perform adequately in conditions up to about 180° C. and 100 Mpa. Under more extreme conditions, however, they fail prematurely. Many alternative materials have been evaluated and rejected for various reasons. For example, polyimides, polyethermide (“ULTEM”), and polyamideimide (“TORLON”) are well known for their excellent durability at high temperature. These materials fail in borehole fluids because the -imid and -amide linkages are subject to rapid hydrolytic degradation at high pH. Polyphenylene sulfide is water resistant but its crystalline melting point, 260° C. is too low for HPHT applications.
SUMMARY OF THE INVENTION
The above disadvantages of the prior art are overcome by means of the subject invention for use of a class of material, polyaryletherketones, that meets the demanding thermal and chemical requirements for downhole applications. This material has the desired high pressure, high temperature (HPHT) performance characteristics, and is also impervious to chemical attack by borehole and formation fluids. A composite material utilizing polyaryletherketones is formed into a shell for use with a downhole logging tool or in a production well. This shell provides structural rigidity and strength at HPHT conditions even in the presence of chemically active materials. Moreover, the shell is tough and resilient so that abrasive contact is considerably reduced during movement in the borehole so it does not damage or otherwise harm items enclosed by the material. The shell is substantially transparent to signal transmission from the logging tool and response from the formation. With this shell, formation evaluation sensors that utilize acoustic, nuclear, resistivity, and electromagnetic technology may be permanently located downhole, positioned in the completion string, and/or in the borehole casing. Properties of the shell can be modified with changes in materials added to the resin in order for the shell to function as casing or coiled tubing. This allows wireline or logging-while-drilling conveyed sensors passing through the casing or coiled tubing to sense the formation and borehole fluid properties.
REFERENCES:
patent: 4662887 (1987-05-01), Turner et al.
patent: 4714509 (1987-12-01), Gruber
patent: 4739325 (1988-04-01), Macleod
patent: 4747988 (1988-05-01), Deeg
patent: 4816556 (1989-03-01), Gay et al.
patent: 5160561 (1992-11-01), Gruber
patent: 5160568 (1992-11-01), Gruber
patent: 5563512 (1996-10-01), Mumby
patent: 5642051 (1997-06-01), Babour et al.
patent: 6084052 (2000-07-01), Aufdermarsh et al.
patent: 0 307 215 (1989-03-01), None
patent: 0 463 611 (1992-01-01), None
patent: 0 505 260 A2 (1992-09-01), None
patent: 0 656 460 A2 (1995-06-01), None
patent: 0 860 584 (1998-08-01), None
patent: WO 97/12166 (1997-04-01), None
RM Archibald & RA Bulstra, “Use of Glass Reinforced Epoxy Resin Tubing in Oman,” SPE 9636, presented at the Middle East Oil Technical Conf. Of the Soc. of Petroleum Engineers, (Mar. 9-12, 1981).
Clark Brian
Thomas, Jr. Stanley R.
Metjahic Safet
Ryberg John J.
Schlumberger Technology Corporation
Segura Victor H.
Zaveri S.
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