Patent CA-3084875-A1 (CA)
Title: Modelling of oil and gas networks
Inventor: SANDNES ANDERS
IPC: E21B43/00
Filed: 2018-12-10
Abstract: An oil and gas network comprises multiple branched flow paths, such as in multi-zonal wells and/or multibranched wells and/or networks including multiple wells, and multiple control points (20, 32) at different branches, wherein the multiple control points (20, 32) may include multiple valves (20) and/or pumps (32) for controlling the flow rate through respective flow paths of the multiple branched flow network. The network is modelled to model the variation of one or more flow parameter(s) (12) in one or more flow path(s) of the network. A method for this modelling includes: generating a long-term model (8) using a first set of data (10, 12) relating to measurements of the flow parameter(s) and the status of the control points (20, 32) over a first period of time, wherein the long-term model (8) describes the relationship between flow rates, the status (10) of control points (20, 32), and measured flow parameters (12) including pressure and/or temperature; generating a short-term model (16) using a second set of data relating to measurements of the flow parameter(s) (12) and the status (10) of the control points (20, 32) over at least one second period of time, wherein the at least one second period of time is shorter than the first period of time, and wherein the short-term model 16 describes the relationship between the status (10) of control points (20) and flow parameters (12) including pressure and/or temperature; and combining the short-term model (16) with the long-term model (8) by: using the short-term model (16) to determine pressure and/or temperature values (12') that will result from the status (10) of one or more control points (20, 32) or from proposed changes to those control points (20, 32); using the determined pressure and/or temperature values (12') from the short-term model (16) along with the status of, or the proposed changes to, the control points (20, 32) as inputs (10, 12') to the long-term model (8) and then using the long-term model (8) to determine flow rate values that will result from those inputs; and thereby obtaining a combined model (16, 8) allowing for estimation of flow rates in real time as well as prediction of the effects of changes in the status (10) of one or more of the control points (20, 32). A method for training a model of this oil and gas network includes: modelling one or more flow parameter(s) (12) in one or more flow path(s) of the network, the modelling including: generating a model (8) using data relating to measurements of the flow parameter(s) (12) and the status of the control points (20, 32) over a period of time; wherein the model describes the relationship between flow rates (14), the status of control points (20, 32), and measured flow parameters (12) including pressure and/or temperature; and wherein generating the model (8) includes training the model (8) under constraints requiring: (i) that the sum of the modelled flow rates from each branch of the flow network that contribute to a combined flow after branched flow paths join at one or more nodes must be equivalent to the respective measured combined flow rate, where a measurement of the combined flow is available, and (ii) that training of the model (8) is suspended or modified for certain flow paths when the status of the control points (20, 32) is such that those flow paths will have zero flow, and/or that a flow rate for an individual flow path or branch must be or is encouraged to zero when an associated valve (20) is closed and/or if a pump (32) required for non-zero flow rate is inactive.