Abstract:
Measurement-while-drilling apparatus includes a 14 MeV neutron accelerator, a near-spaced neutron detector which primarily senses source neutrons and whose output is proportional to source strength, one or more intermediately-spaced epithermal neutron detectors eccentered against the drill collar wall and primarily responsive to formation hydrogen concentration, and a third far-spaced radiation detector, either gamma ray or neutron, primarily responsive to formation density. The intermediately-spaced and far-spaced detector outputs, normalized by the near-spaced detector output, are combined to provide measurements of porosity, density and lithology and to detect gas. A thermal neutron detector and/or a gamma ray detector may also be provided at intermediate spacings to provide additional information of interest, such as standoff measurements and spectral analysis of formation composition. Tool outputs are related to the angular or azimuthal orientation of the measurement apparatus in the borehole.
Abstract:
A method of optimizing production of wells using choke control includes generating, for each well, an intermediate solution to optimize the production of each well. The generating includes using an offline model that includes a mixed-integer nonlinear program solver and includes using production curves based on a choke state and a given wellhead pressure. The method further includes calculating, using a network model and the intermediate solution of each well, a current online wellhead pressure for each well. The method further includes setting the intermediate solution as a final solution based on determining that a difference between the current online wellhead pressure of each well and a prior online wellhead pressure of each well is less than a tolerance amount. The method further includes adjusting, using the final solution of each well, at least one operating parameter of the wells.
Abstract:
A statistical methodology is disclosed to provide time-to-event estimates for oilfield equipment. A method according to the present invention extracts unbiased information from equipment performance data and considers parameters interactions without recourse to data thinning. The analysis explicitly accounts for items of equipment that are still operational at the time of analysis. A method according to the present invention may also be utilized to apply survival analysis to any oilfield equipment components where time-to-event information has been recorded. The method of the present invention allows comparative reckoning between different components present in the system comprising several or many individual components and allows analysis of these components either individually or simultaneously, i.e., in the presence of other components.
Abstract:
A method for optimizing fracture treatments includes interpreting a nominal pump schedule corresponding to a nominal value for each fracture control parameter. The method further includes interpreting environmental variables, and interpreting probability distributions for each of the environmental variables that is uncertain. The method further includes defining an objective function such as a net present value of each fracture treatment over a 365 day period following the fracture treatment. The method includes determining an optimal value for each fracture control parameter according to the objective function by determining the fracture control parameter values that yield the best mean net present value given the variability in the environmental variables as described by their probability distributions.
Abstract:
The invention relates to a method for performing operations of an oilfield having at least one process facilities and at least one wellsite operatively connected thereto, each at least one wellsite having a wellbore penetrating a subterranean formation for extracting fluid from or injecting fluid to an underground reservoir therein. The method involves selectively coupling a plurality of oilfield simulators according to a predefined configuration, each oilfield simulator modeling at least a portion of the oilfield, a first oilfield simulator of the plurality of oilfield simulators receives an oilfield control parameter as an input, identifying an uncertainty parameter associated with a plurality of probable values each corresponding to a weighted probability, a second oilfield simulator of the plurality of oilfield simulators receives the uncertainty parameter as an input, modeling the operations of the oilfield to generate an estimated performance by selectively communicating between the plurality of oilfield simulators, the operations of the oilfield is modeled with a predetermined value of the oilfield control parameter and at least one of the plurality of probable values of the uncertainty parameter; and identifying an optimal value of the oilfield control parameter based on the estimated performance.
Abstract:
A statistical methodology is disclosed to provide time-to-event estimates for oilfield equipment performance data and considers parameters interactions without recourse to data thinning. The analysis explicitly accounts for items of equipment that are still operational at the time of analysis. A method according to the present invention may also be utilized to apply survival analysis to any oilfield equipment components where time-to-event information has been recorded. The method of the present invention allows comparative reckoning between different components present in the system comprising several or many individual components and allows analysis of these components either individually or simultaneously, i.e., in the presence of other components.
Abstract:
A method is disclosed for performing optimal gridding in reservoir simulation, the method comprising: establishing an optimal coarse grid proxy that can replace all or parts of a fine grid with a coarse grid while preserving an accuracy of a predefined simulation model output, the step of establishing an optimal coarse grid proxy including finding, by using an optimizer, a best fit of a coarse grid output to the output of a training set.
Abstract:
A video logging tool is described which is particularly well adapted for production logging of oil or gas wells. The tool has both an end view optical system and a side view optical system for imaging side and end view on a CCD array in a camera.
Abstract:
Measurement-while-drilling apparatus includes a 14 MeV neutron accelerator, a near-spaced neutron detector which primarily senses source neutrons and whose output is proportional to source strength, one or more intermediately-spaced epithermal neutron detectors eccentered against the drill collar wall and primarily responsive to formation hydrogen concentration, and a third far-spaced radiation detector, either gamma ray or neutron, primarily responsive to formation density. The intermediately-spaced and far-spaced detector outputs, normalized by the near-spaced detector output, are combined to provide measurements of porosity, density and lithology and to detect gas. A thermal neutron detector and/or a gamma ray detector may also be provided at intermediate spacings to provide additional information of interest, such as standoff measurements and spectral analysis of formation composition. Tool outputs are related to the angular or azimuthal orientation of the measurement apparatus in the borehole.
Abstract:
A system performs production optimization for oilfields using a mixed-integer nonlinear programming (MINLP) model. The system uses an offline-online approach to model a network of interdependent wells in an online network simulator while modeling multiple interdependent variables that control performance as an offline MINLP problem. The offline model is based on production profiles established by assuming decoupled wells in the actual network of wells. In one example, an amount of lift-gas to inject and settings for subsurface chokes are optimized. An offline solver optimizes variables through the MINLP model. Offline results are used to prime the online network simulator. Iteration between the offline and online models results in a convergence, at which point values for the interdependent variables are communicated to the real-world oilfield to optimize hydrocarbon production.