Patent application number | Description | Published |
20090132981 | Method for Incremental, Timing-Driven, Physical-Synthesis Using Discrete Optimization - A method, data processing system and computer program product for optimizing the placement of logic gates of a subcircuit in a physical synthesis flow. A Path Smoothing utility identifies one or more movable gates based on at least one selection criteria. A set of legalized candidate locations corresponding to one or more identified movable gates is generated. A disjunctive timing graph based on the generated set of legalized candidate locations is then generated. An optimal location of one or more movable gate(s) is determined using a recursive branch-and-bound search and stored in the computing device. | 05-21-2009 |
20100077368 | Method for Bounded Transactional Timing Analysis - A portion of a gate-level netlist representing an integrated circuit design is selected for optimization. A timing window representing the selected portion is made comprising one or more copies of the selected portion. A checkpoint is created for the timing window and stored in a transaction history. One or more changes are then made to the timing window and stored in the transaction history. The changed elements are marked as dirty and stored in the transaction history. After the one or more changes have been made, the timing window is queried for current timing conditions and compared with the checkpoint. If the one or more changes are an improvement, the one or more changes are committed by replicating the one or more changes to the portion of the gate-level netlist. If the one or more changes are not an improvement, the timing window may be restored to the checkpoint. | 03-25-2010 |
20100199243 | METHOD AND SYSTEM FOR POINT-TO-POINT FAST DELAY ESTIMATION FOR VLSI CIRCUITS - The present disclosure is directed to a method for estimating an interconnect delay for a source-to-sink path of a net within a Very Large Scale Integration (VLSI) circuit, the source-to-sink path connecting a source and a sink in the net. The method may comprise estimating a total wire capacitance; calculating a delay contribution based on delay of the source-to-sink path and delay of a plurality of off-path sinks; and estimating the interconnect delay for the source-to-sink path based on the delay contribution. | 08-05-2010 |
20120131530 | PARTITIONING FOR HARDWARE-ACCELERATED FUNCTIONAL VERIFICATION - A circuit design is partitioned for hardware-accelerated functional verification using a directed hypergraph with edge weights that are a function of slack. Slack may be computed as the difference between the early and late ranks for the source of an edge. The weight may further be computed as the difference between the edge's slack and a maximum slack value. In a preferred implementation each vertex also has multiple weights associated with resource requirements of different node types, and the partitioning is constrained to prevent vertex movement that would result in vertex weights for a given partition exceeding a partition resource capacity based on the accelerator architecture. Edge and vertex weights can be recomputed for the next level of partitioning. The partitioning process can be repeatedly iteratively until a termination criterion is met, the termination criterion being based in part on the number of directed cuts in each of the partitions. | 05-24-2012 |
20120317527 | PARTITIONING FOR HARDWARE-ACCELERATED FUNCTIONAL VERIFICATION - A circuit design is partitioned for hardware-accelerated functional verification using a directed hypergraph with edge weights that are a function of slack. Slack may be computed as the difference between the early and late ranks for the source of an edge. The weight may further be computed as the difference between the edge's slack and a maximum slack value. In a preferred implementation each vertex also has multiple weights associated with resource requirements of different node types, and the partitioning is constrained to prevent vertex movement that would result in vertex weights for a given partition exceeding a partition resource capacity based on the accelerator architecture. Edge and vertex weights can be recomputed for the next level of partitioning. The partitioning process can be repeatedly iteratively until a termination criterion is met, the termination criterion being based in part on the number of directed cuts in each of the partitions. | 12-13-2012 |
20130139119 | PARTITIONING AND SCHEDULING UNIFORM OPERATOR LOGIC TREES FOR HARDWARE ACCELERATORS - A circuit design is compiled for hardware-accelerated functional verification by removing internal gates of a uniform operator tree (e.g., an assertion tree) while retaining node information, and partitioning the circuit to optimize connectivity without being constrained by the uniform operator tree. After partitioning, sub-trees are constructed for the partitions, and aggregated to form a master tree. The sub-trees can have leaf nodes at varying depths based on ranks of the leaf nodes, and the master tree can similarly provide inputs from the sub-trees at varying depths based on simulation depths for the sub-trees. The resynthesized master tree is structurally distinct from the original uniform operator tree but, since the inputs are commutative (e.g., OR gates), the functional equivalence of the model is preserved. | 05-30-2013 |
20130275931 | PLANNING FOR HARDWARE-ACCELERATED FUNCTIONAL VERIFICATION - Methods, systems, and computer program products may provide planning for hardware-accelerated functional verification in data processing systems. A method may include receiving, by a computer system, a description of architecture of a hardware accelerator for accelerating functional verification of a circuit design, the architecture including a plurality of logical processors. The method may additionally include receiving, by the computer system, a description of the circuit design having a plurality of gates, and representing, by the computer system, each gate, each stage of the functional verification, and each logical processor as a separate object based on the received description of the architecture and the circuit design. The method may further include representing, by the computer system, relationships between gates as pairwise edges, and defining, by the computer system, a goal state that requires each gate to be scheduled for execution by a logical processor during a stage of the functional verification. | 10-17-2013 |
20140365544 | MULTI-WAY NUMBER PARTITIONING USING WEAKEST LINK OPTIMALITY - Multi-way partitioning is dramatically improved based on “weakest-link” optimality. The set of numbers to be partitioned is subjected to pairwise decomposition with a first partition having a candidate subset (P | 12-11-2014 |
20140365545 | MULTI-WAY NUMBER PARTITIONING USING WEAKEST LINK OPTIMALITY - Multi-way partitioning is dramatically improved based on “weakest-link” optimality. The set of numbers to be partitioned is subjected to pairwise decomposition with a first partition having a candidate subset (P | 12-11-2014 |
Patent application number | Description | Published |
20090101345 | Liner Drilling System with Retrievable Bottom Hole Assembly - A liner drilling system employs a bottom hole assembly that may be retrieved before reaching the total liner depth. The system includes an outer string made up of a liner and a profile nipple. An inner string including a running tool, drill pipe, and a drill lock tool are lowered into the outer string and rotationally and axially locked to the outer string. Drilling may be performed by rotating the inner string, which also rotates the outer string. The operator may retrieve the inner string by pulling the inner string and the liner upward until the upper end of the liner is located at the drilling rig floor. While supporting the liner at the drilling rig floor, the operator retrieves the inner string, then re-runs it back into the outer string. | 04-23-2009 |
20090288821 | Monitoring Flow Rates While Retrieving Bottom Hole Assembly During Casing While Drilling Operations - A bottom hole assembly in a casing-while-drilling operation is retrieved by reducing the density of the fluid in the casing string above the bottom hole assembly, creating an upward force on the bottom hole assembly. As the bottom hole assembly moves upward in the casing string, fluid is pumped into the upper end of the annulus and displaced fluid flows out of the upper end of the casing string. The flow rate of the fluid flowing into the upper end of the annulus and the flow rate of the displaced fluid flowing out of the casing string are monitored and compared. | 11-26-2009 |
20090288839 | Controlling Backflow Pressure During Retrieval of Bottom Hole Assembly - A bottom hole assembly in a casing-while-drilling operation is retrieved by displacing the fluid in the casing string with a less dense fluid than the fluid in the annulus. The bottom hole assembly moves upward in the casing string in response to an upward force due to the different densities of fluid in the casing string and in the annulus. Displaced fluid flows out of the casing string and through a restrictive orifice of a choke. The flow area of the orifice is varied as the bottom hole assembly moves upward to control the rate at which the bottom hole assembly moves upward. | 11-26-2009 |
20090288840 | Retrieval of Bottom Hole Assembly During Casing While Drilling Operations - A bottom hole assembly in a casing-while-drilling operation is retrieved attaching a wireline to the bottom hole assembly. The density of the fluid in the casing string is lightened to a lesser density than the fluid in the annulus, thereby creating a pressure differential between fluid above the bottom hole assembly and fluid below the bottom hole assembly to exert an upward force on the bottom hole assembly. The operator pulls upward on the wireline to assist the upward force in moving the bottom hole assembly up the casing string. | 11-26-2009 |
20090288841 | Circulation System for Retrieval of Bottom Hole Assembly During Casing While Drilling Operations - During casing-while-drilling, drilling fluid is pumped through a conduit leading to a flow passage a casing string gripper and down the casing string. A bottom hole assembly is mounted at a lower end of the casing string for drilling a wellbore. The bottom hole assembly is retrieved by mounting a circulation sub to the casing string below the casing string gripper, the circulation sub having a lateral outlet. A return flow line is connected from the outlet to the circulation system. The operator flows fluid downward in an annulus of the casing string and back up the casing string, causing the bottom hole assembly to move upward. The fluid flowing back up the casing string is diverted through the outlet in the circulation sub to the circulation system without passing through the flow passage in the casing string gripper. | 11-26-2009 |
20090288886 | Retrieval Tool With Slips for Retrieving Bottom Hole Assembly During Casing While Drilling Operations - A casing-while-drilling bottom hole assembly is releasably connected with a casing string. A retrieval tool is run into the casing string and latched to the bottom hole assembly. Slips are mounted to the retrieval tool, the slips being retracted during running in. Differential pressure moves the retrieval tool and bottom hole assembly upward, and the slips engage the casing string to prevent downward movement if the pressure differential drops too low. A flow passage extends through the retrieval tool and the bottom hole assembly. A check valve in the retrieval tool allows downward flow through the flow passage but prevents upward flow, so that fluid may be circulated through the retrieval tool and bottom hole assembly while suspended with the slips. | 11-26-2009 |
20110203794 | Apparatus and Method for Cementing Liner - A method of cementing a liner in a well includes mounting a valve assembly that is biased in a closed position to a running tool assembly. The running tool assembly has a stinger inserted through the valve assembly, retaining the valve assembly in an open position. The stinger has a cement retainer releasably mounted to it. After lowering the running tool assembly into engagement with the liner string, the operator pumps a cement slurry through the stinger and the valve assembly. The operator then pumps the cement retainer down the liner string into latching engagement with a lower portion of the liner string. Afterward, the operator lifts the stinger from the valve assembly, causing the valve assembly to move to the closed position. The valve assembly blocks upward flow of fluid from the well conduit through the valve assembly in the event of leakage of the cement retainer. | 08-25-2011 |
Patent application number | Description | Published |
20120279705 | LINER CEMENTATION PROCESS AND SYSTEM - Present embodiments are directed to coupling a cementation assembly with a hung or set liner string in a well and moving the liner string during a cementation operation. Specifically, for example, a process in accordance with present techniques includes running a cementation assembly into a well on drill pipe and engaging, with a distal end of the cementation assembly, a liner top assembly of a liner string that is positioned downhole in the well, wherein the liner string was previously positioned downhole in the well without being cemented into the well. Further, the process includes latching the cementation assembly with the liner string such that movement of the cementation assembly is translated to the liner string, and flowing cement through the drill pipe and into the liner string while moving the cementation assembly and the liner string. | 11-08-2012 |
20120325499 | LINER TOP PACKER FOR LINER DRILLING - A liner top packer is configured to be secured in a liner string, such as in a liner drilling operation. The packer is actuated from within the liner or packer body. An actuator assembly includes an inner piston, an actuator housing, and an outer piston. A tubular setting tool is moved upwardly through the inner piston, and dogs on the setting tool allow for force to be applied to the inner piston, pressurizing fluid and forcing it to the outer piston to compress a pack off element. The actuator assembly is removed by upward force applied by a foot of the setting tool on the inner piston, the actuator housing, or any other component of the actuator assembly. | 12-27-2012 |
20150068805 | LINER DRILLING BOTTOM HOLE ASSEMBLY LOCATOR SYSTEM AND METHOD - A system and method for locating a bottom hole assembly during liner drilling. The system and method employ a liner and a drill string. The liner may include a stop sub. The drill string may include a bottom hole assembly position indicator. In one or more embodiments, the bottom hole assembly position indicator is configured to engage the stop sub and arrest further advancement of the drill string. | 03-12-2015 |