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Collaborating Authors
Campos, Mario
Protect Wells During Frac Plug Drillouts and Well Flowback Operations for Hydraulically Fractured Wells โ The State of The Art in 2020
Potapenko, Dmitriy (Formerly Schlumberger) | Theuveny, Bertrand (Schlumberger) | Williams, Ryan (Schlumberger) | Moncada, Katharine (Schlumberger) | Campos, Mario (Formerly Schlumberger) | Spesivtsev, Pavel (Schlumberger) | Willberg, Dean (Schlumberger)
Abstract Highly efficient multi-stage hydraulic fractured horizontal wellbores are the dominant completion method for many basins worldwide. This completion workflow is followed with the well start up operations, usually consisting of the frac-plug drill out (FPDO) and the well flowback, designed for preparing the well to the production period. Poor management of FDPO and flowback operations on wells with freshly constructed hydraulic fractures, may jeopardize the investments made in completing the well, and may seriously reduce the wellโs profitability. Previously reported results show that flowback and initial production practices have a major impact on proppant production, maintenance and disposal costs, and the subsequent well performance. In this paper we present the summary of the results obtained from the analysis of over 200 FPDO and flowback operations in the United States and Argentina. These results show that operating a well within the safe stability limits of the hydraulic fracture network minimizes risk of fracture damage and maximizes well performance. Earlier it was shown that typical plug drillout operations consists of a series of underbalance, overbalance and balance periods. Multiple rapid transitions between these conditions and performing plug drillout operations outside of the fracture stability limit, was shown to destabilize the proppant pack and mobilize proppant from the fractures. In this paper we evaluate the impact of the various plug drillout strategies on the proppant distribution in the fracture, and draw conclusions about the strategies that help to preserve fracture conductivity. We also demonstrate that using high-frequency monitoring of the surface rates is key for managing plug drillout operations to minimize mobilization of the proppant from hydraulic fractures. Use of the recently introduced Secure Operating Envelope (SOE) concept was found to be very beneficial for managing well flowback and the production operations. In this paper we demonstrate how the use of the SOE methodology was used for identification of the root cause of the proppant flowback and deriving the appropriate choke management strategy for solving this problem. At the end we conclude that majority of the highlighted problems can be solved through optimizing the well start up operations as a part of the entire well construction process with making changes to the well construction workflow. Implementing certain changes to fracture treatment design should enable maximization of the well production performance and optimize the well economics.
- North America > United States > Texas (0.48)
- North America > United States > Colorado (0.29)
State of the Art of Flow Management for Frac Plug Drillout and Flowback
Potapenko, Dmitriy (Schlumberger) | Theuveny, Bertrand (Schlumberger) | Williams, Ryan (Schlumberger) | Moncada, Katharine (Schlumberger) | Campos, Mario (Schlumberger) | Spesivtsev, Pavel (Schlumberger) | Willberg, Dean (Schlumberger)
Abstract Highly efficient multi-stage hydraulic fractured horizontal wellbores are the dominant completion method for many basins worldwide. One potential weakness of multi-stage hydraulic fracturing is that the later stages of the completion workflow โ frac-plug drill out (FPDO) and flowback โ cause large pressure fluctuations and transient flows through the perforation clusters that coincide with a period of low closure stress in the fractures. The proppant packs in the fractures during this period are fragile and prone to failure. Previously reported results show that flowback and initial production practices have a major impact on proppant production, maintenance and disposal costs and the subsequent well performance. In this paper the results from over 200 FPDO and flowback operations from the United States and Argentina are reviewed. These results show that maintaining a balanced flowrate during FPDO operations is critical for minimizing inadvertent damage to the hydraulic fracture network. The FPDO flowrate balance is the difference between the coiled tubing injection and annular return flowrates. The magnitude and sign of the balance corresponds to the instantaneous flowrate through the open perforation clusters into or out of the hydraulic fracture network. A positive balance rate, or overbalance, injects fluid into the fracture system. A negative balance rate, or underbalance, produces stimulation or formation fluids from the fracture network. Sudden changes between these two regimes creates local flows that can be severe enough to flush large quantities of proppant out of the fractures. Our results show that high-frequency multiphase flowmeters simplify the process of maintaining balance (no inflow, no outflow). Furthermore, close monitoring of any imbalance that develops, and rapid control of the surface choke and injection rate, can provide for an efficient operation while protecting the integrity of the fracture system. Early monitoring of flowback and production with a high frequency flowmeter was shown to be extremely useful technique for optimizing well productivity during well clean-up. This paper also shows how a dual energy gamma ray multiphase flowmeter successfully quantified proppant produced during FPDO and flowback. Examples of the dynamics of sand production are shown, as well as correlations to events of excessive underbalance conditions. At the end of the paper we show that most of the highlighted problems can be solved through making changes to the well construction workflow and accounting for relationships between various well operations. Incorporation of this workflow enables early prediction of well performance issues and their efficient resolution.
Abstract An optimized stimulation and flowback strategy was devised from formation structure and reservoir properties in the Powder River Basin (PRB) to keep fluid production rates and bottomhole flowing pressure (Pwf) inside a secure operating envelope (SOE) of operational parameters. Keeping operations within the SOE helps ensure Long-term preservation of propped fracture connectivity to the wellbore by minimizing proppant flowback and the associated pinch-off risk. Reduction and/or elimination of a remedial lateral cleanout. Reduction of sand-related well and surface facilities failures such as worn standing valves, junked pumps, and abrasion-related surface leaks. Reduction of proppant waste and its disposal associated costs by keeping proppant inside the fracture network and not flowing it back. Well completion design and proppant placement are understood across the industry, but more recently long-term stimulation integrity has become more of a focus. A look-back analysis of offset wells showed considerable amounts of proppant produced during flowback. Traditional flowback approaches focus on surface rate control rather than differential pressure across the proppant pack. The pressure and flow rate are both drivers for proppant production risk. A geomechanical earth model and stimulation design were used to establish an advanced flowback strategy to minimize risk of proppant flowback. Communication protocols between operations and engineering teams, a tailored SOE, and a flow simulator were then used to make on-time choke size decisions that maximized early-time production and minimized proppant flowback. Using this advanced flowback strategy, an average of 30 pounds of proppant per well was estimated to be produced using hourly samples during the early production of the well compared with an average of 75,000 pounds of proppant per well recovered before the implementation of this strategy. The engineered flowback approach was implemented in a total of 15 wells with repetitive success that materially helped position these wells as top quartile producers within the PRB. Based on the results of the implementation of this methodology, the engineered flowback approach was adopted as a standard operating practice within the production management organization of a major oilfield service provider in all assets in which wells are completed using hydraulic fracturing stimulation.
- North America > United States > Wyoming (0.61)
- North America > United States > Montana (0.61)
- North America > United States > Wyoming > Powder River Basin (0.99)
- North America > United States > Montana > Powder River Basin (0.99)
- South America > Argentina (0.89)
- (2 more...)
Cost-Conscious Corrosion Control
Cavallaro, Brandon (Schlumberger) | Clayton, Richard (Schlumberger) | Campos, Mario (Schlumberger)
Abstract From the summer of 2014 to the summer of 2015, global oil prices declined by nearly 60%. The initial impact of this decline on unconventional assets was to reduce or stop drilling and completion activity, but the lower oil price also had a significant impact on cash flow from existing wells. Operators were able to achieve some reduction in operating expenses through contract renegotiations with suppliers, but cash flow margins from sales of oil and gas from production operations were severely impacted. In fields with higher operating expenses due to corrosive environments, the need to manage costs became even more critical. For example, in onshore fields with highly corrosive reservoir fluids, production chemicals can account for more than 40% of monthly operational expenses. Reducing chemical spend can therefore seem like an easy way to reduce lifting costs. However, a reduction in treatment volume can lead to mechanical integrity issues that are more costly to remediate than to prevent, therefore requiring a strategy to balance cost reduction and mechanical integrity preservation. A cost-conscious corrosion management strategy was developed and implemented for an onshore, sour-bacteria-laden oil from a shale oil development in south Texas. The strategy addressed treatment cost per barrel produced, the effectiveness of chemical formulations, metallurgies of downhole and surface facility components, and the cost of remediation. This full-spectrum corrosion management approach had a positive financial impact across the field. Key performance indicators were defined and tracked, and a workflow was implemented to manage the large amounts of data from wells in the field. A lifecycle data management system was employed to not only capture failures, but also facilitate root cause analysis. This afforded the opportunity to design-out repeat failure mechanisms, for example by changing downhole metallurgies. This workflow supported the on-time optimization of chemical pumping rates, which reduced operating costs without ceding equipment integrity. This workflow reduced time spent toiling over corrosion management, thus saving on engineering resources. Despite a challenging economic environment, corrosion management must be maintained in operational budgets. The example of the successful cost-conscious methodology used in the south Texas field shows that even dramatically reduced budgets can still support the safe, environmentally sustainable operation of an oilfield asset.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.71)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Sabinas - Rio Grande Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Maverick Basin > Eagle Ford Shale Formation (0.99)
- (7 more...)