Nearly every step in the development of a reservoir is critical in achieving the goal of maximizing hydrocarbon production. An initial geological analysis provides an understanding of subsurface conditions and an estimated ultimate recovery. Reservoir simulations and cellular gridding provide insight into fluid flows. Wellbore data helps geologists confirm or refine geologic models and completion engineers obtain an accurate understanding of wellbore conditions that influence oil well completion design.
The outcome of each step depends upon the volume and quality of discipline-specific data, software tools, and experience of the reservoir team. Individual data sets are important to geologists, geophysicists, and reservoir, drilling, and completion engineers involved in reservoir development. The value of any dataset greatly increases when data are integrated with, and evaluated in the context of, other data sources. As an example, let’s explore how data integration and visualization enhance oil well completion design.
Geological Models Provide Baseline Understanding
Seismic data visualized in a 3D environment allows geologists to explore and analyze subsurface formations, determine targets, and identify geologic structures that could complicate hydrocarbon extraction. With the ability to transform seismic data into a detailed 3D geologic model, geologists and reservoir engineers can easily:
- Explore the complexity of horizons, isochores, reverse faults, major fault gaps, fault-wedge contours, salt domes, and other geologic scenarios to guide reservoir development.
- Locate oil, gas, and water zones to plan well trajectories and completion methods that isolate productive from non-productive zones.
- Identify production zones relative to the overall reservoir structure to determine the appropriate number of frac stages for a horizontal well.
Geological models provide the baseline for evaluating reservoir potential and determining the appropriate development strategies. When additional data are incorporated into the analysis, reservoir and production engineers gain a more accurate and detailed understanding of reservoir conditions.
Petrophysical Properties Guide Oil Well Completion Design
Petrophysical data can also be incorporated into the geologic model. Wellbore data from logs, gamma ray, and core analyses characterize the petrophysical properties of the completion zone. These data play an important role in assessing the potential producing interval to estimate the economic value of a wellbore before committing to its development.
Completion engineers can determine the most appropriate completion designs—screen, liner, gravel pack, cased hole, single string, multiple zones, multilateral or a combination—and any required treatments based on strata, permeability, and porosity of rock surrounding the wellbore.
A detailed understanding of a reservoir’s geologic and petrophysical attributes will also help completion engineers anticipate and mitigate problems that could potentially diminish well performance such as:
- fines migration settling on the well bottom and blocking a portion or all of a liner’s perforations
- tight well spacing that could lead to thief zones that degrade the performance of a producing well
- excessive gas rates resulting in higher frictional losses and high back-pressure across perforations
- coning leading to unwanted water production and water disposal costs
The ability to visualize the interplay of geological and petrophysical variables associated with the completion zone enables engineers to fine-tune the completion design to ensure the selection and placement of components—pumps, casing, cementing, liners, fluids, proppants, chemicals, and safety valves that maximize both production and safety.
Utilize Insight From Oil Well Completion Designs of Nearby Wells
Completion engineers can further improve their ability to optimize oil well completion designs by studying the designs and production data of nearby wells or wells. Access to comprehensive information associated with nearby wells or wells with similar geologic formations and the ability to visualize and analyze the integrated data helps completion engineers achieve optimum oil well completion designs in the following ways:
- Determine which oil well completion designs have been successful and avoid those that have been problematic.
- Anticipate potential problems associated with specific geology, petrophysics, completion designs, and proactively plan mitigation strategies.
- Use time-step visualization (4D) to see how initial oil well completion designs and subsequent recovery methods have impacted well performance and production.
Reservoir engineers are far better prepared to make critical decisions regarding reservoir development when they can review the effectiveness of nearby oil well completions in the context of the geological and petrophysical properties that influenced design, or determine which of several alternative designs successfully balanced costs and risks to optimize production over the life of the well.
CoViz 4D Guides Oil Well Completion Design
One of the biggest challenges for completion engineers is obtaining access to the variety of data sources that characterize the complexity of subsurface environments. Different data acquisition methods, various data formats, and a variety of discipline-specific software programs create vital, yet disparate data. However, software solutions like CoViz 4D give completion engineers immediate access to critical geological, petrophysical, and other relevant data sources without the need to be concerned about sources and data formats.
Different data acquisition methods, various data formats, and a variety of discipline-specific software programs create vital, yet disparate data.
Using a data registry that links to the various data sources, CoViz 4D can integrate the data and present it in a common format for 3D and 4D (time step) visualization and analysis. CoViz 4D provides a common environment that allows geologists, geophysicists, well planners, and completion and drilling engineers to collaboratively explore, evaluate, and determine development plans, beginning with well location and extending all the way to tertiary recovery methods, that have the best chance of maximizing hydrocarbon recovery.