Patent Application
20230259670
In the oil and gas industry, hydrocarbon fluids are located in porous reservoirs far beneath the Earth's surface. Using data gathered from seismic tools and exploratory wells, a reservoir simulation model of the reservoir may be created. The model numerically represents the reservoir and simulates properties of the reservoir, including fluid flow properties, on a computer. The model may be used to determine the volume of recoverable hydrocarbons in the reservoir and how to best obtain said hydrocarbons. This may be achieved by simulating porosity and permeability throughout the reservoir. As such, it is important that the model accurately represents the reservoir in both porosity and permeability.
This 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.
The present disclosure presents, in accordance with one or more embodiments, methods and non-transitory computer readable mediums for correcting a model having a plurality of cells and representing a reservoir. The method includes obtaining a log of the reservoir, determining, by a computer processor, a log porosity-thickness for each segment of the log of the reservoir, determining a test permeability-thickness relating to each segment of the log of the reservoir using a dynamic pressure transient analysis, determining a relationship between the test permeability-thickness and the log porosity-thickness, determining a model flow capacity and a model storage capacity for the model, determining a calculated flow capacity using the model storage capacity and the relationship, determining a ratio of the calculated flow capacity to the model flow capacity, correcting the model by applying the ratio to each cell, and planning and executing a reservoir production plan based on the model.
The non-transitory computer readable medium stores instructions having functionality for obtaining a log of the reservoir, determining, by a computer processor, a log porosity-thickness for each segment of the log of the reservoir, determining a test permeability-thickness relating to each segment of the log of the reservoir using a dynamic pressure transient analysis, determining a relationship between the test permeability-thickness and the log porosity-thickness, determining a model flow capacity and a model storage capacity for the model, determining a calculated flow capacity using the model storage capacity and the relationship, determining a ratio of the calculated flow capacity to the model flow capacity, correcting the model by applying the ratio to each cell, and planning and executing a reservoir production plan based on the model.
Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.
In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.
The reservoir (100) is made of a plurality of rock grains (102). The spaces between the rock grains (102) are called the pores (104). The pores (104) may or may not contain a fluid, such as a hydrocarbon. The hydrocarbons may be in a gas phase, a liquid phase, or a mixture of the two phases. Further, the pores (104) may contain more than one type of fluid such as a mixture of hydrocarbons and water. Porosity is the ratio of pore (104) volume to total volume of the sample (110) as depicted in Equation (1) where ϕ=porosity; vp=volume of the pores (104) in the sample (110); and vt=total volume of the sample (110). Porosity is measured as a fraction or a percentage.
Permeability is the measurement of the reservoir's (100) ability to transmit fluids. In other words, porosity is the measurement of the interconnected pores (104) of the reservoir (100). Permeability is measured in darcies or millidarcies. Permeability is represented in
A wellbore (108) is shown running through the reservoir (100). A wellbore (108) is a hole that has been drilled from the surface of the Earth. A wellbore (108) is often drilled into a reservoir (100) to gather data and determine if the reservoir (100) could be a hydrocarbon reservoir. More than one wellbores (108) may be drilled into the reservoir (100) at various locations to analyze the reservoir (100) at said locations. In further embodiments, a wellbore (108) is drilled into the reservoir (100) to produce hydrocarbons or water. Data used from seismic tools, reservoir logging tools, and rock samples taken from the wellbore (108) may be used to create a reservoir simulation model of the reservoir (100).
In one or more embodiments, the model may describe the geometry of the reservoir, such as the location of its upper and lower bounding surfaces and it lateral extent and may describe the spatial variation of the porosity and permeability of the reservoir (100). To be as accurate as possible, the model may be made of a plurality of cells each having their own porosity and permeability. Permeability is one of the most difficult to measure and hence least well constrained parameters when creating the reservoir simulation model. As such, permeability simulated by the model is often corrected based on permeability measurements obtained using a core sample taken from the wellbore (108).
However, core samples are limited in number due to the time and cost of acquiring samples while drilling and coring a wellbore (108). As such, models that correct permeability based on a core sample are frequently inaccurate. Therefore, methods and systems that allow a model to be corrected based on more accessible and accurate data is beneficial. As such, embodiments herein present systems and methods for correcting the model based on a relationship between the dynamic flow capacity of a wellbore (108) obtained from pressure transient analysis and the storage capacity of the reservoir (100) obtained from log measurements.
Specifically, the log (200) depicted in
Often, the exact depth of the reservoir (100) is unknown, and the log (200) is used to determine the depth of the top and bottom of the reservoir (100). Among other things, the reservoir (100) may be distinguished in the log (200) by noting where there is a section of high porosity. In
As can be seen by the log (200) depicted in
Initially, a log (200) of the reservoir (100), divided into a plurality of segments (202), is obtained (S300). The log (200) of the reservoir (100) may be similar to the log (200) depicted in
A test permeability-thickness relating to each segment (202) of the log (200) of the reservoir is determined using a dynamic pressure transient analysis and the computer processor (S304). A dynamic pressure transient analysis is run on the wellbore (108) to measure the flow rate of the reservoir (100) which is equal to the test permeability-thickness. Each segment (202) start depth and end depth (i.e., depth interval) that were used to determine the log porosity-thickness may be the same start depth and end depth of each test permeability-thickness.
More specifically, the test permeability-thickness, or, in other words, the dynamic pressure transient analysis permeability-thickness is obtained by perforating the well across the reservoir (100) and flowing the well. A pressure gauge, located downhole, is used to record the pressure during flow and when the well is shut in. This pressure data is analyzed to obtain the test permeability-thickness.
In further embodiments, a test flow capacity of the entire reservoir (100) may be determined by summing each test permeability-thickness of each segment (202) of the reservoir (100). A log (200) storage capacity of the entire reservoir (100) may be determined by summing each log (200) porosity-thickness of each segment (202) of the reservoir (100).
A relationship (400) is determined between the test permeability-thickness and the log (200) porosity thickness using the computer processor (S306). The relationship (400) is determined by plotting the test permeability-thickness versus the log (200) porosity-thickness of each segment (202) of the reservoir (100).
A model of the reservoir (100) is created using software stored on the computer processor. The software may be any modeling software known in the art such as Petrel™. The reservoir (100) in the model is created by a plurality of cells. Each cell has a model porosity-thickness and a model permeability-thickness value. A model flow capacity and a model storage capacity for the model is determined using the computer processor (S308). The model flow capacity is the summation of the model permeability-thickness for each cell across the reservoir (100). The model storage capacity is the summation of the model porosity-thickness for each cell across the reservoir (100). Because porosity is a more known variable in the model, the model storage capacity and the log storage capacity should be similar to one another. Because permeability is a more unknown variable in the model, the test flow capacity and the model flow capacity may differ, requiring the model flow capacity to be adjusted.
A calculated flow capacity is determined using the model storage capacity, the relationship (400), and the computer processor (S312). As previously explained, the relationship (400) is represented by a mathematical relationship (400) between the test permeability-thickness and the log (200) porosity-thickness. For example, the mathematical relationship (400) may be Equation (2), below, where y=flow capacity and x=storage capacity.
y=0.17567x2.73317 Equation (2)
The model storage capacity value may be inserted into the equation as the x value to determine the calculated flow capacity (the y-value). A ratio of the calculated flow capacity to the model flow capacity is determined using the computer processor (S312). The ratio is determined by dividing the calculated flow capacity, determined from Equation (2), by the model flow capacity, determined by summing the model permeability-thickness of each cell across the reservoir (100). The permeability-thickness values of each cell of the model is corrected by applying the ratio to each cell (S314). This process may be done automatically by the computer processor and the chosen model software.
A reservoir (100) production plan may be planned and executed based on the model (S316) to facilitate the safe and efficient production of hydrocarbons from the reservoir (100). The reservoir (100) production plan may include determining a well path through the reservoir (100) and drilling into the reservoir (100) using a drilling system and utilizing the well path. The plan may further include the type and surface location of the wellbores to be drilled, according to the well path, to reach and penetrate the reservoir (100), and from which to produce hydrocarbons. The plan may include defining the type, size, and location of surface facilities, such as production rigs, pipelines, and GOSPs.
The plan may also include specifying the type of completions to use, including whether wells should be uncased or contain slotted liners, whether hydraulic fracturing, acidizing, or both, is utilized, and whether surface or downhole pumps are needed to produce the hydrocarbons. The plan may further determine whether the injection of fluid, typically water, is required at locations within the reservoir (100) to raise, maintain, or slow the decline in reservoir pressure. Further, the plan may include enhanced recovery methods, such as the injection of steam to reduce the viscosity of oil. The reservoir (100) production plan may be influenced by the assessment of geological, geographical, and economic factors. The geological factors may include the critical desorption pressure and the expected ultimate recovery (EUR) volume of gas from the reservoir (100).
The computer (502) can serve in a role as a client, network component, a server, a database or other persistency, or any other component (or a combination of roles) of a computer system for performing the subject matter described in the instant disclosure. The illustrated computer (502) is communicably coupled with a network (530). In some implementations, one or more components of the computer (502) may be configured to operate within environments, including cloud-computing-based, local, global, or other environment (or a combination of environments).
At a high level, the computer (502) is an electronic computing device operable to receive, transmit, process, store, or manage data and information associated with the described subject matter. According to some implementations, the computer (502) may also include or be communicably coupled with an application server, e-mail server, web server, caching server, streaming data server, business intelligence (BI) server, or other server (or a combination of servers).
The computer (502) can receive requests over network (530) from a client application (for example, executing on another computer (502)) and responding to the received requests by processing the said requests in an appropriate software application. In addition, requests may also be sent to the computer (502) from internal users (for example, from a command console or by other appropriate access method), external or third-parties, other automated applications, as well as any other appropriate entities, individuals, systems, or computers.
Each of the components of the computer (502) can communicate using a system bus (503). In some implementations, any or all of the components of the computer (502), both hardware or software (or a combination of hardware and software), may interface with each other or the interface (504) (or a combination of both) over the system bus (503) using an application programming interface (API) (512) or a service layer (513) (or a combination of the API (512) and service layer (513). The API (512) may include specifications for routines, data structures, and object classes. The API (512) may be either computer-language independent or dependent and refer to a complete interface, a single function, or even a set of APIs. The service layer (513) provides software services to the computer (502) or other components (whether or not illustrated) that are communicably coupled to the computer (502).
The functionality of the computer (502) may be accessible for all service consumers using this service layer. Software services, such as those provided by the service layer (513), provide reusable, defined business functionalities through a defined interface. For example, the interface may be software written in JAVA, C++, or other suitable language providing data in extensible markup language (XML) format or other suitable format. While illustrated as an integrated component of the computer (502), alternative implementations may illustrate the API (512) or the service layer (513) as stand-alone components in relation to other components of the computer (502) or other components (whether or not illustrated) that are communicably coupled to the computer (502). Moreover, any or all parts of the API (512) or the service layer (513) may be implemented as child or sub-modules of another software module, enterprise application, or hardware module without departing from the scope of this disclosure.
The computer (502) includes an interface (504). Although illustrated as a single interface (504) in
The computer (502) includes at least one computer processor (505). Although illustrated as a single computer processor (505) in
The computer (502) also includes a non-transitory computer (502) readable medium, or a memory (506), that holds data for the computer (502) or other components (or a combination of both) that can be connected to the network (530). For example, memory (506) can be a database storing data consistent with this disclosure. Although illustrated as a single memory (506) in
The application (507) is an algorithmic software engine providing functionality according to particular needs, desires, or particular implementations of the computer (502), particularly with respect to functionality described in this disclosure. For example, application (507) can serve as one or more components, modules, applications, etc. Further, although illustrated as a single application (507), the application (507) may be implemented as multiple applications (507) on the computer (502). In addition, although illustrated as integral to the computer (502), in alternative implementations, the application (507) can be external to the computer (502).
There may be any number of computers (502) associated with, or external to, a computer system containing computer (502), each computer (502) communicating over network (530). Further, the term “client,” “user,” and other appropriate terminology may be used interchangeably as appropriate without departing from the scope of this disclosure. Moreover, this disclosure contemplates that many users may use one computer (502), or that one user may use multiple computers (502).
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112(f) for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
