To maximize production from low-permeability reservoirs, well planners strive to locate wells without creating well interference that reduces pressure or production. It’s often a balancing act, but with modern well planning software providing a detailed, 3D model of reservoir geology and other subsurface features, well planners can determine well paths that minimize well interference.
However, even the best well plans encounter the reality of subsurface uncertainties during the drilling and completion stages. Did the actual wellbore deviate from the recommended well plan? If so, where is the new lateral relative to previously-drilled laterals? Is the completion strategy delivering the expected results? Is a newly-completed well negatively affecting the production of nearby wells? With the aid of software tools that integrate and visualize a wide range of subsurface data, reservoir and production engineers can answer these questions with greater confidence.
Well Interference Insight From Microseismic Data
Using microseismic data to monitor and evaluate results of fracking, stage by stage, reservoir teams can obtain a detailed understanding of any impact on existing wells as subsequent wells are drilled and completed. By combining geologic, wellbore and laterals, and microseismic data, engineers create a detailed 3D visualization of the reservoir to depict well locations, determine the effectiveness of frac stages and treatments, and determine if, and to what extent, newly-completed wells may be interfering with surrounding wells.
Monitor the Fracturing Process in Near-Real-Time
Interference between wells during hydraulic fracturing can undermine the effectiveness of a treatment by diverting energy to previously stimulated stages. Near-real-time acquisition of microseismic data via surface and downhole monitors and visualization of that data—in conjunction with existing well trajectories, perforations, stratigraphy, and fault geometries—allow reservoir engineers to:
- Accurately determine frac event locations, magnitude, stage, and plane characteristics;
- Analyze completion design and frac treatment effectiveness as the stages progress;
- Evaluate the fracture network; and
- Identify possible well interference among proximate wells.
As additional data are acquired throughout the fracking process, incorporating them into the 3D visualization in near-real-time facilitates a close assessment of completion design and frac treatment effectiveness. This detailed level of analysis allows completion engineers to incrementally modify treatments in the event they are not producing the expected results.
A time-series animation (4D) of microseismic event geometry captured during a hydraulic fracturing process provides completion engineers a unique perspective of the development and extent of the fracture network. An extended time-series animation of microseismic events associated with all of the completed laterals tied to a well pad allows well planners and reservoir engineers to see how previous development decisions have affected current well performance.
Changes in Pressure or Production Metrics
As additional wells are completed, microseismic data analysis becomes critical in determining if pressure or production changes in nearby wells are the results of well interference, and to what extent. Microseismic analysis can help isolate the location of well interference. Based on the analysis of the interference, as well as reviewing wells with similar geological and petrophysical properties (all of the information easily accessible and visualized in detail in a 3D environment), well engineers can develop strategies to mitigate the impact of well interference. Those remedies may include:
- Volume reductions for successive hydraulic fracturing treatments
- Choking back a well to increase pressure and boost production
- Steam or water injections to boost reservoir pressure
- Sidetracking, an expensive option, to locate a lateral in a more favorable region within the strata
Lessons learned from well interference should influence future well planning. For example, interference from wells placed too closely points to more distant spacing. Wells unaffected by interference may indicate that the geology can tolerate closer spacing.
Visualization Puts Microseismic Data in Context
Well interference can undermine the long-term productivity of a reservoir, resulting in high recovery costs. Well planning software like WellArchitect helps well planners and drilling planners to locate wells with trajectories and spacing to maximize reservoir drainage. Data integration and visualization software like CoViz 4D allows reservoir engineers to monitor the hydraulic fracturing process in near-real-time to evaluate progress and results.
The wealth of information and powerful 3D visualization capabilities allow reservoir engineers to explore, evaluate, and diagnose well interference with the goal of mitigating current problems and preventing future ones.
With a detailed, 3D visualization of microseismic data presented in combination with other relevant subsurface data such as geologic formations, existing well locations, and microseismic data from previously-completed wells, reservoir engineers gain a better understanding of the impact of any well interference. The wealth of information and powerful 3D visualization capabilities allow reservoir engineers to explore, evaluate, and diagnose well interference with the goal of mitigating current problems and preventing future ones.