Intelligent and/or segmented completions such as staged fracture completions and/or multi-zone injection wells have been utilized quite extensively in the oilfield since the late 1990's. Their application has become more widespread since the 2004 oil price increase and worldwide technology acceptance. The main applications in the Middle East for intelligent completions' have been in controlling multi-lateral completions where each flow control valve is placed at the junction for each lateral leg—often an open hole lateral. These types of intelligent completion applications allow a lateral to be choked back or shut-off should unwanted production occur. This manipulation of the well completion can be done without resorting to intervention through coiled tubing or tractor operations which are themselves inherently risky operations. Intelligent completions are conventionally operated by use of hydraulic or electric control lines run in with the completion, adding to the complexity of installation.
In parallel with this technology acceptance, passive inflow control systems, (hereinafter referred to as “ICD”s) and/or injection control systems have become extremely popular for open-hole long horizontal completions especially in locations such as in the Middle East carbonate reservoirs. The main drivers have been controlling fracture contribution to the wellbore and balancing for wellbore hydraulics effects in long horizontal or deviated wells.
In addition selective segmented completions have been used widely to facilitate the stimulation treatment of multi-zone and/or long horizontal wells. In this case, the selectivity is provided by a series of valves that is actuated to direct stimulating fluids (acid, water, sand, proppant, polymer, solvents or other such fluids) for the purpose of selectively injecting into the specific segment of the well being targeted.
The ICD style of completion is often particularly attractive to the operator and especially the drilling departments due to the relatively low risk and cost of the installation phase. However the long-term benefits of the passive inflow control completion system are compromised should water production enter the wellbore. The ICD will limit the production of water, but does not allow it to be effectively shut off without intervention. Similarly, current ICD type completions complicate access to the formation for treatments such as stimulation treatments, clay stabilization, water conformance injection etc.
In addition, an ICD is by default designed before installation phase. Once the ICD is in place, there is little chance to change its characteristics (flow versus pressure differential), and therefore their success relies on the accurate characterization of the formation conductivity with the borehole.
Attempts have been made to provide dissolvable members. Commonly-assigned U.S. Patent Application Publ. No. US2007/0181224 discusses reactive alloy materials for targeted control. One composition consists essentially of one or more reactive metals in major proportion, and one or more alloying elements in minor proportion, with the provisos that the composition is high-strength, controllably reactive, and degradable under defined conditions. Compositions may exist in a variety of morphologies, including a reactive metal or degradable alloy processed into an alloy of crystalline, amorphous or mixed structure that may constitute the matrix of other compositions, for instance a composite.
Other attempts have been made to provide dissolvable members to control downhole fluid flow in oilfield applications. For example, commonly-assigned U.S. Patent Application Publ. No. 2009/0151949 discusses self dissolvable alloys for perforating. U.S. Patent Application Publ. No. 2004/0014607 discusses dissolvable encapsulation of chemicals for oilfield treatment purposes. Commonly-assigned U.S. Patent Application Publ. No. 2011/0067889 discusses a hydraulic regulating mechanism for disposal in a well. The mechanism includes a degradable metal based element and a swellable component for hydraulic regulation. The mechanism is configured for ease of setting and removal by allowing degrading of the metal based element upon exposure to certain downhole conditions which may trigger shrinking of the swellable component. Commonly-assigned U.S. Patent Application Publ. No. 2011/0048743 discusses a dissolvable bridge plug configured with components for maintaining anchoring and structural integrity for high pressure applications. Embodiments of the plug are configured such that these components may substantially dissolve to allow for ease of plug removal following such applications. Commonly-assigned U.S. Patent Application Publ. No. 2008/0210423 discusses circulated degradable material assisted diversion methods for well treatment in completed wells. Commonly-assigned U.S. Patent Application Publ. No. 2008/0105438 discusses whipstocks and deflectors comprising a degradable composition.
All of the commonly-assigned patent applications identified above are hereby incorporated by reference herein.
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