Abstract: A memory management unit (MMU) has a cache for storing address translation entries (ATEs) corresponding to virtual addresses. If an ATE is present for a requested virtual address, then it is translated to the physical address and sent to main memory. If the MMU cache misses, the virtual address is hashed to obtain the physical address for a group of ATEs. After hashing, a decision is made whether to prefetch the group of ATEs or not. If so, the group is loaded into the data cache. Another determination is made; in this case whether to continue or not. If the request is not valid, the process is terminated. If the request is still valid, then a tablewalk is performed on the group to find the matching entry, which is loaded into the MMU cache. The virtual address is translated to obtain the physical address which is sent to main memory.

Abstract: Methods and apparatus for utilizing a downhole deployment valve (DDV) to isolate a pressure in a portion of a bore are disclosed. Any combination of fail safe features may be used with or incorporated into the DDV such as redundant valve members, an upward opening flapper valve or a metering flapper below a sealing valve. In one aspect, a barrier or diverter located in the bore above a valve member of the DDV permits passage through the bore when the valve member is open and actuates when the valve member is closed. Once actuated, the barrier or diverter either stops or diverts any dropped objects prior to the dropped object reaching and potentially damaging the valve member. In another aspect, the tool string tripped in above the DDV includes an acceleration actuated brake that anchors the tool string to a surrounding tubular if the tool string is dropped.

Abstract: The present generally relates to apparatus and methods for instrumentation associated with a downhole deployment valve or a separate instrumentation sub. In one aspect, a DDV in a casing string is closed in order to isolate an upper section of a wellbore from a lower section. Thereafter, a pressure differential above and below the closed valve is measured by downhole instrumentation to facilitate the opening of the valve. In another aspect, the instrumentation in the DDV includes sensors placed above and below a flapper portion of the valve. The pressure differential is communicated to the surface of the well for use in determining what amount of pressurization is needed in the upper portion to safely and effectively open the valve. Additionally, instrumentation associated with the DDV can include pressure, temperature, seismic, acoustic, and proximity sensors to facilitate the use of not only the DDV but also telemetry tools.

Abstract: The present invention involves methods and apparatus for permanent downhole deployment of optical sensors. Specifically, optical sensors may be permanently deployed within a wellbore using a casing string. In one aspect, one or more optical sensors are disposed on, in, or within the casing string. The optical sensors may be attached to an outer surface of the casing string or to an inner surface of the casing string, as well as embedded within a wall of the casing string. The optical sensors are capable of measuring wellbore parameters during wellbore operations, including completion, production, and intervention operations.

Abstract: The present generally relates to apparatus and methods for instrumentation associated with a downhole deployment valve or a separate instrumentation sub. In one aspect, a DDV in a casing string is closed in order to isolate an upper section of a wellbore from a lower section. Thereafter, a pressure differential above and below the closed valve is measured by downhole instrumentation to facilitate the opening of the valve. In another aspect, the instrumentation in the DDV includes sensors placed above and below a flapper portion of the valve. The pressure differential is communicated to the surface of the well for use in determining what amount of pressurization is needed in the upper portion to safely and effectively open the valve. Additionally, instrumentation associated with the DDV can include pressure, temperature, and proximity sensors to facilitate the use of not only the DDV but also telemetry tools.