PRODUCTION ENTITIES
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Introduction
Oil and gas production first starts with the drilling of a well to test models for hydrocarbon accumulations envisioned by geologists and geophysicists. Once the well is drilled and it encounters a hydrocarbon reservoir, various other specialists become involved.
For example, responsibility for production falls to petroleum engineers, who are charged with installing and maintaining equipment such as casing to produce the formation fluids, which may include gas, oil, and water, in quantities that vary with time.
If the well encounters two or more producing reservoirs, equipment known as completion strings can be installed to allow production from each to remain separate, as shown in the following figure.
Alternatively, if the well encounters two or more producing reservoirs, completion strings can be installed to allow production from each to be combined (commingled).
These engineers manage fluid flow from the reservoir and monitor flow rate by observing the quantity of fluids collected in surface storage facilities each day. As well, engineers try to forecast the future production rate for each producing interval.
It is the job of production accountants to track the fluids through various delivery systems, including tanks, batteries, facilities, pipelines, and tankers. Regulatory agencies may require reporting of types and quantities of produced fluids grouped or measured at different points of this delivery system. Many commercial sources of production information only have the information available at these aggregate levels.
Once several wells are drilled, production reporting becomes more complicated, and the number of production entities increases.
For example, production from several wells and all their production strings may have their fluids commingled into a single storage facility, and the aggregate volume may be recorded on several levels, including production platforms, gas leases, reservoirs, production units, etc. In addition, production may be controlled by a lease that only allows production from a deep zone (called deep rights). Alternatively, wells may be grouped as a unit, which may be set up to maximize production. The governing regulatory body may allow production to be reported as a unit. Finally, production may be reported for a field, which can have numerous reservoirs, wells, leases, pools, and units.
As well, versions of production data from different sources may exist and may vary over time.
These complexities of production reporting and the various types of production entities can all be tracked in the Production Module of PPDM.
Business Process Overview
Purpose
The Production Module provides a means of describing and managing information from oil and gas production.
Description
Once a well is drilled and completed, fluid production from the well is delivered through various systems, allocated to various production entities, reported to the company and to regulatory agencies, and measured and forecasted. Injected or produced fluids and all data associated with production must be tracked.
Key Business Processes
Types of Producing Entities
Specialists in production are required to track, allocate, report, or forecast fluids being produced from or injected into a reservoir. A number of entities can report data on reservoir fluids. In addition, methods used for identification of these Production Reporting Entities (PDENs) may vary between organizations as well as over time.
Oil and gas production may be allocated to and reported from any of the following structures:
- Business associate (partner)
- County
- Facility
- Field
- Land Rights
- Other objects
- Pool
- Production Lease Unit
- Production String Formation
- Production Strings
- Reserve entities (classified or unclassified)
- Wells
The Production Module pays particular attention to the problem of identifying those entities that can report data on reservoir fluids.
Versions of Production Data
Authorized and preferred versions of production data may be available for the same production entity. Authorized information is known or assumed to be correct, while information contained on production reports may contain inaccuracies or discrepancies.
Nevertheless, companies and jurisdictional bodies must retain data values as reported, even when the values are known to be incorrect. The Production Module allows you to track production from a variety of sources, one that reflects the original reported values and another that may track the final authorized values, as created by production accountants.
Tracking Production Data
In general, categories of production data include volumes, volume disposition, allowable levels, fluid analysis, forecasts, and operating history.
In particular, petroleum engineers are involved with measuring volumes of fluids produced (or injected, flared, sold, etc.). To do this, they monitor flow rate by observing the quantity of fluids collected in surface storage facilities each day. From this comes a measurement of volume over a period of time (usually a day). It is also possible to install flow meters in the well and infer the volume produced per day. Usually, these readings are conducted as part of a program of periodic well testing, with the assumption that the flow rate between testing periods can be calculated. The purpose of well testing is to collect information that allows the pressure-volume-temperature regime to be determined.
If production is commingled, calculating how much flow comes from each reservoir becomes more complicated. However, individual flow rates are directly observable and must be recorded in order to control the rate of reservoir depletion. Volumes contributed from each reservoir are calculated later (called back allocation) and may be revised based on additional tests or correction factors.
In the case of commingled production, the production engineer back allocates to each producing zone using allocation factors calculated from periodic testing.
Production volumes may be actual, estimated or forecast. Forecast volumes based on specific classes of reserves reporting (proven, probable etc.) may be tracked as an aid to comparing actual to expected volumes.
The Production Module is set up to track all of this information.
Relationships Between Production Entities
Production may be transferred from one production entity to another. For example, in a particular reporting month, a well may be reconnected from one facility to another. Furthermore, while a pipeline from a string is being changed, production from the string may have to be trucked to a third facility.
You can capture the transfer of production volumes from one production entity to another in the Production Module.
Different Data Sources
Production data can also be purchased from commercial sources, which often obtain their information from regulatory agencies. This data may be reported by lease, well, or reservoir, for example. Data may be purchased from more than one vendor, which conceivably means that more than one version of the data could exist.
Provisions are made in the Production Module for data versions from different sources that may vary over time.
Model Overview
Key data concepts are shown in the summary diagram in the next section and expanded upon in the section after it.
Key Data Concepts Overview
Key Data Concepts
Entities That Can Report Production
A production entity refers to any entity that reports production. This entity may represent physical installations, such as a production well string; a spatial construct, such as lease or reservoir; an organizational concept, such as a business unit; or an analysis concept, such as a reserve entity.
The model must take into account any entity for which production, injection, transportation, or storage of reservoir fluids is reported. These entities could be physical installations such as a well or production string, a spatial construct such as a lease or reservoir, or an organizational concept such as a business unit.
In PPDM, each of these entities is modeled as an explicit subtype of the table PDEN. At present, a number of subtypes are defined: business associate, county, facility, field, other, pool, production lease or unit, production string, production string formation, reserve entity, reserve entity classification and well.
Production Reporting Entity (PDEN)
The production reporting entity (PDEN) is the cornerstone of the Production Module. It represents an alias or reporting version for any entity that production, etc., may be reported for. This allows a producing entity to be included in many different kinds of production reports generated by many different organizations, such as business partners or regulatory agencies.
Each organization usually will have its own scheme for uniquely identifying producing entities. Data vendors will also provide identifiers that are consolidated from many different organizations (usually regulatory) and manipulated so that they are unique within the scope of the vendor’s data.
Associating Corporate Data With Production Reporting Data
Sometimes, the data received on a production report is inaccurate. For example, dates may be incorrect. Often, it is necessary to keep the reported data intact, while preventing these errors from compromising the quality of the authorized data.
In PPDM, authorized well information is stored in the Well Module, while reported data may be stored in the Production Module. The relationship between each production entity and its authorized data is managed by the PDEN sub-type tables, as described in the Tables and Columns section of this document.
Producing Entity Versions and Aliases
Producing entities such as wells or facilities are identified in a variety of ways. Authorized identifiers for each of these producing entities are normally stored in the appropriate business table in PPDM (WELL_ALIAS or FACILITY ALIAS).
When production is reported for each of these entities, an identifier for that producing entity will also be noted. Often, this identifier is the same as the identifier for the business entity the production references (such as the well name or facility code). In some cases, different names, codes, or identifiers are provided on a production report. These can be managed in the Production Module independently if desired.
Data vendors may supply information on producing entities as well as on production reporting entities. The Production Module makes provisions for different versions of a producing entity by source of data. The approach is consistent with how versioning is handled for well data.
Production Data
The current scope of the Production Module includes the following types of data:
- Allocation Data
- This type of data allocates a single measured volume to several production reporting entities.
- Fluid Analysis Data
- This data includes analysis of the reservoir fluids produced or handled by a production reporting entity.
- Flow Measurement Data
- This type of data is real-time flow measurement data and is usually a summary of very detailed SCADA information.
- Forecast Data
- This data includes forecasted production and parameters used for decline analysis.
- Volume Data
- This category includes volumetric data of fluids that have been produced, injected, transported, processed, or stored.
- Status History Data
- This data represents the status history of a production reporting entity.
