Method for determining an outlet configuration of a liner

Abstract

A method for determining an outlet configuration of a liner usable for stimulating a reservoir comprises the steps of (a) obtaining a desired fluid outflux distribution along one or more segments of the reservoir, each segment corresponding to a portion of the liner; (b) determining, for each portion, a number of outlets according to: the desired fluid outflux distribution (Q), a predefined outlet size and a difference between an annulus pressure and a liner pressure within the portion; (c) evaluating, for each portion, whether an outlet distribution according to the number of outlets of the predefined outlet size satisfies one or more outlet distance constraints within the portion; (d) repeating, if the outlet distribution of at least one portion does not satisfy the one or more outlet distance constraints, the steps (b) and (c) for the at least one portion with an adjusted outlet size as the predefined outlet size.

1 . A computer-implemented method for determining an outlet configuration of a liner usable for stimulating a reservoir, the method comprising the following steps:
 a. obtaining a desired fluid outflux distribution along one or more segments of the reservoir, each segment corresponding to a portion of the liner;   b. determining, for each portion of the liner, a number of outlets according to: the desired fluid outflux distribution, a predefined outlet size and a difference between an annulus pressure and a liner pressure within the portion;   c. evaluating, for each portion, whether an outlet distribution according to the number of outlets of the predefined outlet size satisfies one or more outlet distance constraints within the portion; and   d. if the outlet distribution of at least one portion does not satisfy the one or more outlet distance constraints, repeating, for the at least one portion, the steps b. and c. with an adjusted outlet size as the predefined outlet size.   
     
     
         2 . The method of  claim 1 , further comprising:
 deriving, for each portion of the liner, an annulus portion rate and a liner portion rate based on the desired fluid outflux distribution along the one or more segments of the reservoir;   estimating, based at least in part on the derived liner portion rates, the liner pressure; and   estimating, based at least in part on the derived annulus portion rates, the annulus pressure.   
     
     
         3 . The method of  claim 2 , wherein each segment is associated with a desired segment acid coverage and a segment length; and
 wherein deriving the annulus portion rate and the liner portion rate for a portion is based at least in part on the desired segment acid coverage and the segment length of the segment.   
     
     
         4 . The method of  claim 2 , wherein estimating the liner pressure comprises:
 calculating, for each pair of adjacent portions, a pressure difference between the pair of adjacent portions.   
     
     
         5 . The method of  claim 4 , wherein calculating the pressure difference between a pair of adjacent portions comprises:
 calculating a friction pressure based at least in part on a friction factor, in particular a Fanning friction factor, a diameter, a pipe length, a velocity and/or a fluid density.   
     
     
         6 . The method of  claim 2 , wherein estimating the annulus pressure within each portion is further based on a pressure within the reservoir, a pipe length L, a viscosity μ, B, k, S and a factor depending on boundary conditions of the reservoir, in particular a well type such as a vertical or horizontal well. 
     
     
         7 . The method of  claim 1 , wherein the one or more outlet distance constraints comprise:
 a distance between adjacent outlets of a portion not exceeding a predefined upper threshold, in particular 100 ft;   a distance between adjacent outlets of a portion exceeding a predefined lower threshold, in particular 25 ft;   an outlet size being within a range of a predefined minimum and maximum value, in particular 2-8 mm, in particular 3-4 mm; and/or   an outlet spacing distortion not exceeding a predefined value, in particular 3, wherein the outlet spacing distortion is a ratio between a maximum distance between two outlets within a portion and a minimum distance between two outlets within the portion.   
     
     
         8 . The method of  claim 7 , wherein the adjusted outlet size comprises:
 a reduced outlet size if the distance between adjacent outlets of the portion exceeds the predefined upper threshold; or   an increased outlet size if the distance between adjacent outlets of the portion is below the predefined lower threshold.   
     
     
         9 . The method of  claim 1 , further comprising:
 calculating, using the number of outlets, a flow rate, a wellhead pressure and/or an acid coverage which satisfies a predetermined set of stimulating constraints.   
     
     
         10 . The method of  claim 9 , wherein calculating is done by optimizing, in particular using an objective function, values of the flow rate, the wellhead pressure and/or the acid coverage; preferably wherein the flow rate is prioritized over the wellhead pressure and/or the acid coverage. 
     
     
         11 . The method of  claim 10 , wherein the optimizing further comprises:
 setting an initial value, in particular 0.25 bbl/min, as the value of the flow rate; and/or   setting an initial value, in particular 1000 psia, as the value of the wellhead pressure.   
     
     
         12 . The method of  claim 9 , wherein the predetermined set of stimulating constraints comprises:
 an annulus pressure along a predefined section of portions of the one or more portions not exceeding a fracturing pressure along the predefined section of portions, preferably wherein the section is on an annulus side of a lower completion of the liner; and/or   the wellhead pressure not exceeding a predefined threshold value; and/or   the flow rate not exceeding a maximum rate capacity of a corresponding pump; and/or   a jet velocity of fluid entering the reservoir exceeding a predefined wormholing threshold; and/or   a provided acid dosage exceeding a minimum amount of acid dosage required for wormhole penetration and skin reduction.   
     
     
         13 . The method of  claim 1 , further comprising:
 performing a feasibility check of the construction of the liner comprising the provided outlet distribution for each of the one or more portions based on a set of construction constraints.   
     
     
         14 . The method of  claim 13 , further comprising:
 determining that the feasibility check of the construction is negative; and   repeating, for at least one portion of the one or more portions step b. and/or c. with an adjusted outlet size as the predefined outlet size.   
     
     
         15 . The method of  claim 1 , wherein the method comprises a step of providing the outlet distribution for each portion that satisfies the one or more outlet distance constraints; and wherein providing preferably comprises:
 causing a display of one or more visualizations associated with the construction of the liner comprising the one or more portions.   
     
     
         16 . The method of  claim 1 , further comprising:
 issuing a notification, in particular a flag displayed on a display, whenever a constraint is not satisfied.   
     
     
         17 . The method of  claim 1 , further comprising:
 segmenting the reservoir along the liner by applying one or more packers, in particular swellable packers, to obtain the one or more segments of the reservoir.   
     
     
         18 - 24 . (canceled) 
     
     
         25 . A data-processing apparatus comprising means for performing the method of  claim 1 . 
     
     
         26 . A computer program or a computer-readable medium comprising a computer program, wherein the computer program comprises instructions, which when executed by a computer, cause the computer to perform the method of  claim 1 . 
     
     
         27 . A method for manufacturing a liner usable for stimulating a reservoir, the method comprising the steps of:
 determining an outlet configuration of a liner according to  claim 1 ; and   arranging the outlets along the liner according to the determined outlet configuration.