编译 | 大安 TOM
For unconventional reservoirs, E&P companies are continually adjusting various stimulation treatment parameters to improve well performance. Current completion designs manipulate stage length, treatment rate, number of clusters, perforations per cluster and entry hole diameter to achieve more fractures per wellbore. The challenge is stimulating each cluster efficiently to achieve these outcomes in a timely and cost-effective manner.
Halliburton’s Prodigi intelligent fracturing service incorporates data from thousands of stages along with real-time information to deliver uniform fluid and proppant distribution. This data-rich approach coupled with an advanced control system architecture allows the service to maximize cluster efficiency to a degree not possible with manual manipulation.
With the Prodigi service, the breakdown process is optimized for every stage of every well, maximizing stimulation placement consistency along the lateral, thus eliminating underperforming stages. Since the primary benefit of a more uniform distribution of fluid and proppant across clusters is achieved, several secondary benefits have been observed within unconventional basins, including lower treating pressure, faster stage pumping times and reduced screenouts. Further, because the process is automated, each stage is treated consistently to reduce overall variability of the stimulation execution, stage to stage and well to well. To date, the Prodigi service has been implemented on more than 5,500 stages within 12 different basins for 37 unique E&P companies to help improve well performance.
Validation with fiber-optic monitoring
Wells instrumented with fiber-optic sensors have revealed that treatments with manual rate control cause an uneven flow distribution across the clusters that can vary as much as 14 bbl/min between individual clusters at full treatment rate. Applying the Prodigi service mitigates this disproportion of flow across clusters by intelligently breaking down the formation using algorithms that directly control the operation treatment rate. During a recent study, measurements verified by permanent fiber, flow distribution was shown to vary by only 0.1 bbl/min flow rate across the entire perforation cluster set when the Prodigi service was deployed.
Furthermore, far-field measurements from fiber-optic monitoring on offset wells have revealed broader fracture geometry on the Prodigi service stages, indicating more uniform fracture networks than conventional stages. Thus, treatment stages using the service can help ensure a more effective stimulated reservoir.
Williston Basin results
Recently, an E&P company operating within the Williston Basin joined Halliburton to engineer a solution that would help improve cluster efficiency while pumping. Hydraulic fracturing within the Williston Basin poses multiple challenges with reservoir heterogeneity and the varying thickness of target zones, leading to inconsistent stimulation treatments. To address these challenges, Halliburton recommended its Prodigi intelligent fracturing service, which provides a repeatable and consistent approach to stimulation with adaptive, instantaneous changes to pumping rates, optimizing formation breakdowns during fracture treatments. The Prodigi service takes an engineered approach to maximize the cluster efficiency of each and every stage, whereas a traditional formation breakdown focuses on delivering the designed rate based on personal preference of the individual running the operation. The Prodigi service uniquely adapts the treatment using real-time pumping data to automatically and intelligently adjust pump rates to achieve optimal cluster efficiency.
To validate the performance of the Prodigi service, Halliburton provided real-time monitoring of the fluid and proppant distribution within each cluster using its StimWatch stimulation fiber-optic monitoring service.
Applying the Prodigi service yielded significant performance gains within the customer’s well. With the permanent installation of fiber-optic cable within the well, the StimWatch service provided the uniformity index in real time, which gave a measurement of the distribution of fluid and proppant between each cluster. The uniformity index enabled a method to rank the success of various stages. For comparison, two stages were pumped within the same horizontal well and were executed with the same perforation design and the same maximum rate of treatment. Figure 1 charts the performance of traditional pumping: StimWatch service data reveal uneven fluid placement within each cluster. By contrast, Figure 2 shows the effectiveness of the Prodigi service: automatic real-time adjustment to pumping rates yielded a more even distribution of proppant and fluid within the clusters, resulting in significantly more consistent and effective fluid distribution across the clusters.
FIGURE 1. The chart depicts the results of a traditional pumping stage in a horizontal well. (Source: Halliburton)
FIGURE 2. The chart depicts the results of the Prodigi service-enabled pumping stage in the same horizontal well. (Source: Halliburton)
Haynesville/Bossier Shale results
When recently targeting the Haynesville/Bossier Shale formations in northern Louisiana, an E&P company determined that the toe stages consistently proved to be extremely difficult to stimulate, resulting in multiple screenouts for numerous wells. The HP/HT environment of the Haynesville/Bossier Shale challenges the ability to place proppant during a fracturing treatment because of the characteristic high-formation stresses. Thus, stimulation operations are frequently not pumped as designed, and delivering consistent fracture treatments is extremely difficult.
Halliburton studied the screenout tendencies of stimulation operations in the Haynesville/Bossier and recognized a strong correlation with the number of clusters accepting treatment fluid. To help improve cluster efficiency and uniformity, Halliburton introduced its Prodigi service to optimize the formation breakdown during fracturing treatment. By effectively breaking down all the clusters evenly at the beginning of the stage, the Prodigi service allows proppant to be placed more evenly along the wellbore. Traditionally, formation breakdown focused on delivering the designed rate as fast as possible. The Prodigi service adapts to downhole conditions and autonomously adjusts pump rates during treatment.
Results from the Prodigi service have been notable for this E&P company—screenouts were eliminated, and 100% of the designed proppant was placed in nearly every stage due to improved cluster efficiency and formation breakdown (Figure 3). Furthermore, the designed treating rate was achieved earlier than when using traditional breakdown methods. The Prodigi service reduced the overall treatment time on average by 10 minutes per stage while observing a lower average treating pressure. Further, the Prodigi service reduced variability for the overall stimulation treatment, resulting in the operator improving forecast completion activities by eliminating screenouts.