For purposes of preparing a typical well for the production of oil or gas, completion equipment is installed in the well. The completion equipment may partition segments of the well and the surrounding hydrocarbon reservoir into isolated completion zones. For example, for a given lateral or deviated wellbore of the well, the completion equipment may include a lateral tubing string that is installed to communicate produced well fluid from the wellbore. The tubing string may include sand screens to inhibit sand production; flow control devices to regulate the rate at which well fluid is produced; and packers to form annular seals between the tubular string and the surrounding wellbore to form the isolated zones.
The summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In accordance with an example implementation, an article includes a non-transitory computer readable storage medium that stores instructions, which when executed by a computer cause the computer to, based at least in part on a reservoir model of a geologic region containing a wellbore, determine a streamline field in the region. The streamline field includes streamlines that intersect a fluid contact of interest in the region and intersect the wellbore. The instructions when executed by the computer further cause the computer to determine arrival times at points along the wellbore associated with the fluid contact boundary of interest based at least in part on fluid travel for the boundary being constrained to occur along the streamlines; and determine partitions associated with isolated completion zones based at least in part on the determined arrival times.
In accordance with another example implementation, a system includes a memory and a packer advisor engine. The memory stores data that represents streamlines that intersect a fluid of interest in a geologic region and intersect a wellbore in the geologic region. The packer advisor engine includes a processor to determine arrival times at points along a wellbore for a boundary associated with the fluid of interest; constrain fluid travel for the boundary to occur along streamlines; and partition the wellbore into isolated zones based at least in part on the arrival times.
In accordance with yet another example implementation, a technique includes, based at least in part on a reservoir model of a geologic region containing a wellbore, determining a streamline field in the region. The streamline field includes streamlines that intersect a fluid of interest in the region and intersect the wellbore. The technique also includes determining arrival times at points along the wellbore for a boundary associated with the fluid of interest based at least in part on fluid travel for the boundary being constrained to occur along the streamlines; and determining packer placement for a completion installed in the wellbore based at least in part on the arrival times.
Advantages and other features will become apparent from the following drawings, description and claims.
In the following description, numerous specific details are set forth but implementations may be practiced without these specific details. Well-known circuits, structures and techniques have not been shown in detail to avoid obscuring an understanding of this description. “An implementation,” “example implementation,” “various implementations” and the like indicate implementation(s) so described may include particular features, structures, or characteristics, but not every implementation necessarily includes the particular features, structures, or characteristics. Some implementations may have some, all, or none of the features described for other implementations. “First”, “second”, “third” and the like describe a common object and indicate different instances of like objects are being referred to. Such adjectives do not imply objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner. “Coupled” and “connected” and their derivatives are not synonyms. “Connected” may indicate elements are in direct physical or electrical contact with each other and “coupled” may indicate elements co-operate or interact with each other, but they may or may not be in direct physical or electrical contact. Also, while similar or same numbers may be used to designate same or similar parts in different figures, doing so does not mean all figures including similar or same numbers constitute a single or same implementation.
Referring to
As depicted in
Although not shown in
Techniques and systems are disclosed herein, which use reservoir model-based fluid arrival times for purposes of designing completion segmentation (e.g. determining the number of packers and the corresponding packer positions), as well as sizing inflow equipment (cross-sectional flows of inflow control devices (ICDs), flow areas of flow control valves (FCVs), and so forth) in an extended reach or multiple zone completion for purposes of achieving optimal reservoir sweep efficiency through zonal allocation of the well production rate.
More specifically, systems and techniques are disclosed herein, which use a reservoir model, such as simplified reservoir model 200 of
More specifically, in accordance with example implementations, the reservoir model 200 spatially discretizes the reservoir into three dimensional fluid element volumes and may be used to model the inflow of well fluids into the wellbore 210 in discrete time steps (beginning at time zero when fluid through the wellbore 210 begins). As an example, the reservoir model 200 may be based at least in part on one or more of the following: logging-while-drilling (LWD) properties acquired using LWD tools during drilling of the wellbore 210; properties derived from one or more borehole surveys using receivers run into one or more pilot holes and/or one or more offset wells; a field scale reservoir description; knowledge of structural surfaces in the vicinity of the wellbore 210 derived from geo-navigation model used in the placement process of the wellbore 210; properties derived from a wellbore seismic surveys; properties derived from a surface seismic surveys; and so forth.
Referring to
Because there is no flow in the direction perpendicular to a given streamline 310, each streamline 310 extends along a no-flow boundary so that the boundary may be traced from a packer location into the reservoir along that streamline 310. Techniques and systems are described herein, which use the streamlines as a basis for flow dependent reservoir partitioning, which allows tracing individual completion zones upstream into the reservoir.
More specifically, in accordance with example implementations, each streamline 310 arrives at an associated position 320 of the wellbore 210. It is noted that a given wellbore position 320 may be associated with a group, or bundle, of multiple streamlines 310. A certain time exists for a fluid contact boundary of interest (a water/oil boundary, for example) to travel from the reservoir to a particular wellbore position 320 along an associated streamline 310. Thus, for a given streamline 310 that intersects the wellbore 210, every elemental fluid volume along that line may be assigned a unique time for that elemental fluid volume to flow into the wellbore sink. In accordance with example implementations, a single arrival time is assigned to each of the streamlines 310 intersecting the wellbore 210 based on the point where the streamline 310 pierces through the fluid contact boundary of interest, and these arrival times may then be used to partition the wellbore 210 and reservoir, and determine flow equipment parameters, as further described herein.
The packer advisor engine 404 uses a reservoir model 402 to determine a streamline field 410. In this manner, in accordance with example implementations, the packer advisor engine 404 advances the reservoir model 402 through a limited number of time steps until an equilibrium flow state is reached and a pseudo-steady state pressure distribution develops. For this state of the reservoir model 402, the packer advisor engine 404 constructs streamlines that are orthogonal to the iso-pressure contours and uses these streamlines to, for each streamline that intersects the wellbore, determine an associated arrival time 412. More specifically, a fluid boundary contact of interest is first identified for the packer advisor engine 404, such as, for example, by a user inputting data into the engine 404 that identifies the fluid contact boundary of interest or the user otherwise informing the engine 404 (e.g., via a graphical user interface (GUI) about the fluid boundary contact of interest. As an example, the fluid boundary contact of interest may be an oil-water boundary.
Using the identified fluid contact boundary of interest, the packer advisor engine 404 identifies the streamlines that interest the wellbore and the fluid boundary contact of interest, and for each identified streamline, the packer advisor engine 404 identifies a corresponding fluid element for the streamline where the streamline intersects the boundary of interest. The packer advisor engine 404 may then determine a time (i.e., an “arrival time”) for the fluid element to travel along the streamline to the wellbore.
Thus, the packer advisor engine 404 uses a streamline approach to reservoir flow modeling. For a given time step, there is no cross-flow between streamline bundles flowing into the neighboring completion compartments. If the rate is kept unchanged for a given completion through several simulation time steps, there is relatively little change occurring in the streamline geometry over that time because the underlying pressure field is not changing substantially across the reservoir.
In accordance with example implementations, the packer advisor engine 404 applies a clustering algorithm that partitions the wellbore based on local variances of the arrival times (within the determined partition windows) or at least determines a partitioning that reduces the local variances below an acceptable threshold. As a result of the clustering, the packer advisor engine 404, in accordance with example implementations, identifies a number of packers to be installed in the wellbore and the placement of the packers.
It is noted that, in general, local variances in the arrival times may, in general, be reduced with an increasing number of packers. However, the relative variance reduction may significantly taper off as the number of packers reaches a threshold, and increasing the number of packers above this threshold may have limited to no additional benefit. To guide the partitioning, in accordance with example implementations, the packer advisor engine 404 displays a representation of a partitioning quality versus the number of partitions so that the user may decide a point at which increased partitioning has diminished returns. In accordance with example implementations, the packer advisor engine 404 may determine the partitioning quality by applying an inverse function to the variance.
Referring to
In accordance with example implementations, the clustering algorithm clusters the arrival times in a number of iterations, with each iteration producing a predefined number of clusters based on the variance of the arrival times. In accordance with example implementations, a given clustering iteration may contain an initial pass in which one or more partition locations (i.e., the boundaries of the partition window) correspond to wellbore locations that are unsuitable for setting a packer due the local wellbore conditions. The packer advisor engine 404, in accordance with example implementations, adjusts the partition locations that were identified in the initial pass to ensure that the partition locations correspond to suitable locations for setting packers.
In this manner, in accordance with example implementations, the packer advisor engine 404 consults data representing wellbore conditions to check whether one or more partition locations that were identified by the clustering algorithm are suitable for packer placement. As an example, the packer advisor engine 404 may check the resulting packer locations against such wellbore conditions, as washout (caliper) and shale content to ensure that the respective packers could be set properly. In accordance with example implementations, the packer advisor engine 404 may adjust the packer locations in relatively small increments until suitable packer locations that correspond to the number of packer locations identified by the clustering are determined.
As an example,
Thus, referring to
More specifically, in accordance with example implementations, a technique 900 (
Referring back to
In accordance with example implementations, the flow control equipment advisor 450 equalizes average arrival times from fluid contacts for different streamline bundles that are associated with a particular partition. If the required timing to a conformant break through along the entire completion is represented by “T,” then, in general, the flow control equipment advisor 45 modifies the individual compartment rate (called “Qi”) as follows:
where “QiNEW” represents the new calculated flow rate for the partition; and “TARRIVALi” represents the average arrival time for partition i. In accordance with example implementations, if the TARRIVALi time is greater than T for a given partition, then the flow control equipment advisor relaxes the constraint imposed by Eq. 1 for that compartment because the rate for that partition cannot be significantly increased above the fully open rate through additional choking of the neighboring partitions. Depending on the particular implementation, the flow control equipment advisor 450 may display calculated flow control equipment parameters, such as the calculated flow rates for the partitions.
Thus, referring to
In accordance with example implementations, the system 400 of
The hardware 1110 may include, for example, one or multiple central processing units (CPUs) 1112 and a memory 1114. In general, the memory 1114 is a non-transitory storage medium that may store data 1118, program instructions 1116, data structures, and so forth, depending on the particular implementation. The memory 1114 may be formed from non-transitory storage devices, such as one or more of the following: semiconductor storage devices, phase change memory devices, magnetic storage devices, optical storage devices, memristors, and so forth. In accordance with example implementations, the instructions 1116 may include instructions that when executed by the CPU(s) 1112 cause the CPU(s) to form the packer advisor engine 404 and the flow control equipment advisor engine 450. In accordance with example implementations, the CPU(s) 1112 may execute the instructions 1116 to form all or part of any of the techniques that are disclosed herein, such as techniques 800, 900, 1000 and 1200 (discussed below).
The data 1118 may include data representing arrival times, variances, a reservoir model parameter, a streamline flow field, partitioning parameters, flow control parameters, arrival time averages, average flow wellbore flow rate, and so forth. The physical machine 1100 may include other hardware 1110 and machine executable instructions 1160. In this regard, the physical machine 1100 may include such additional hardware 1110 as a network interface 1120, input devices 1124 (a keyboard, a mouse, and so forth) and a display 1120. Moreover, the machine executable instructions 1160 may form other software entities, such as an operating system 1170, applications 1174, device drivers 1172, and so forth.
Other implementations are contemplated which are within the scope of the appended claims. For example, in accordance with further example implementations, although
While a limited number of examples have been disclosed herein, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations.
This application claims the benefit of, and priority to, U.S. Patent Application Ser. No. 62/155,073, filed Apr. 30, 2015, which application is expressly incorporated herein by this reference in its entirety.
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