Characterize the production performance of Bakken Wells. You need to correlate the decline rates of Bakken wells to well/reservoir/completion Parameters, and finally make contour maps.
Task 1. Production Data Analysis
The objective of this task is to collect and obtain information on variables of interest in a systematic way to prepare the required data for
studying the decline rates of Bakken wells.
Each person must select 3 Bakken wells with at least 12-month production history. Work with your teammates to locate your wells over the Bakken such that you cover the area of interest in the Bakken, ND.
Task 1.1. Data Collection
This subtask focuses on collecting information on the well/reservoir/completion Parameters. The required data include:
- Well name
- Well location (Easting/Northing)
- Well Type (vertical, horizontal)
- Completion Type (sliding sleeve, plug & perf)
- Lateral length (Lw)
- Number of Frac Stages (Nfrac)
- Proppant Type (sand, ceramic, mixed)
- Proppant amount (lb mass)
- Frac fluid type (water, X-linked gel, etc.)
- Reservoir properties from reports, such as lithology of the producing layer and Permeability (if available)
Task 1.2. Decline Curve Analysis
This subtask will involve calculating the decline rates of Bakken wells.
Decline Curve Analysis:
Production decline analysis is a traditional means of identifying well production problems and predicting well performance and life based on real production data. It uses empirical decline models that have little fundamental justifications. These models include
- Exponential decline (constant fractional decline)
- Harmonic decline, and
- Hyperbolic decline.
While the hyperbolic decline model is more general, the other two models are degenerations of the hyperbolic decline model. These three models are related through the following relative decline rate equation (Arps, 1945):
1/q.dq/dt = -bqd
where b and d are empirical constants to be determined based on production data. When d = 0, Eq (8.1) degenerates to an exponential decline model, and when d = 1, Eq (8.1) yields a harmonic decline model. When 0 < d < 1, Eq.1 derives a hyperbolic decline model. The
decline models are applicable to both oil and gas wells.
Model Identification
Production data can be plotted in different ways to identify a representative decline model. If the plot of log(q) versus t shows a straight line (Figure 8-1), according to Eq (8.20), the decline data follow an exponential decline model. If the plot of q versus Np shows a straight line (Figure 8-2), according to Eq (8.24), an exponential decline model should be adopted. If the plot of log(q) versus log(t) shows a straight line (Figure 8-3), according to Eq (8.32), the decline data follow a harmonic decline model. If the plot of Np versus log(q) shows a straight line (Figure 8-4), according to Eq (8.34), the harmonic decline model should be used. If no straight line is seen in these plots, the hyperbolic decline model may be verified by plotting the relative decline rate defined by Eq (8.1). Figure 8-5 shows such a plot. This work can be easily performed with computer program UcomS.exe.
Task 1.1. However,
1. Engineering Report (Word)
2. Recommendation Presentation (PowerPoint)
3. All Excel Workbooks used to complete project (Excel)