Down-hole monitoring cable with hydrogen absorbing layer

Abstract

A hydrocarbon monitoring cable including resistance to development of defects in a fiber optic core thereof. The core defect resistance may be in the form of resistance to defect causing agents of a downhole environment such as hydrogen. This may be obtained through the use of a carbon layer about the fiber optic core. However, in light of the differing coefficients of thermal expansion between such a carbon layer and an outer polymer jacket, an intermediate polymer layer of a third coefficient of thermal expansion may be disposed between the carbon and jacket layers. Thus, the intermediate polymer layer may be of a third coefficient of thermal expansion selected so as to avoid fiber optic defect causing thermal expansion from the downhole environment itself. Additionally, the monitoring cable may include an electrically conductive layer about the fiber optic core that is positively charged to repel other positively charged fiber optic defect causing agents of the downhole environment. Furthermore, a polymer-based absorbing layer for absorbing such defect causing agents may be disposed about the fiber optic core for protection.

Description

technical field [0001] The embodiments relate to a hydrocarbon monitoring cable for downhole condition monitoring in hydrocarbon wells. In particular, embodiments of the hydrocarbon monitoring cable are configured for placement and relatively continuous monitoring of the well over an extended period of time, perhaps between about 11 / 2 and 5 years. Background technique [0002] Various hydrocarbon applications include the use of wirelines deployed within hydrocarbon wells. For example, during the production of hydrocarbons from a well, a hydrocarbon cable may be placed within the well to monitor the conditions of the well during production. There may be an optical fiber core running through the cable to obtain well condition information such as temperature. In fact, due to the nature of the fiber optic, the temperature profile of the well can be obtained by readings from every point along the fiber core. Such information can be used to infer production data useful in produ...

AI Technical Summary

Problems solved by technology

[0006] Regardless of the shielding type, a conventional hydrocarbon monitoring cable of actual size, if left in place for downhole monitoring, will typically cause its fiber optic capacity to fail in the order of months

The high pressure, high temperature, hydrogen environment of a typical hydrocarbon well throughout production ultimately renders the cable ineffective for continuous fiber optic monitoring of downhole conditions

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