Evaluation and Effect of Fracturing Fluids on Fracture Conductivity in Tight Gas Reservoirs Using Dynamic Fracture Conductivity Test PDF Download

Author: Juan Correa Castro
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
Unconventional gas has become an important resource to help meet our future energy demands. Although plentiful, it is difficult to produce this resource, when locked in a massive sedimentary formation. Among all unconventional gas resources, tight gas sands represent a big fraction and are often characterized by very low porosity and permeability associated with their producing formations, resulting in extremely low production rate. The low flow properties and the recovery factors of these sands make necessary continuous efforts to reduce costs and improve efficiency in all aspects of drilling, completion and production techniques. Many of the recent improvements have been in well completions and hydraulic fracturing. Thus, the main goal of a hydraulic fracture is to create a long, highly conductive fracture to facilitate the gas flow from the reservoir to the wellbore to obtain commercial production rates. Fracture conductivity depends on several factors, such as like the damage created by the gel during the treatment and the gel clean-up after the treatment. This research is focused on predicting more accurately the fracture conductivity, the gel damage created in fractures, and the fracture cleanup after a hydraulic fracture treatment under certain pressure and temperature conditions. Parameters that alter fracture conductivity, such as polymer concentration, breaker concentration and gas flow rate, are also examined in this study. A series of experiments, using a procedure of "dynamical fracture conductivity test," were carried out. This procedure simulates the proppant/frac fluid slurries flow into the fractures in a low-permeability rock, as it occurs in the field, using different combinations of polymer and breaker concentrations under reservoirs conditions. The result of this study provides the basis to optimize the fracturing fluids and the polymer loading at different reservoir conditions, which may result in a clean and conductive fracture. Success in improving this process will help to decrease capital expenditures and increase the production in unconventional tight gas reservoirs.

Author: Jose Domingo Romero Lugo
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
Hydraulic Fracturing stimulation technology is used to increase the amount of oil and gas produced from low permeability reservoirs. The primary objective of the process is to increase the conductivity of the reservoir by the creation of fractures deep into the formation, changing the flow pattern from radial to linear flow. The dynamic conductivity test was used for this research to evaluate the effect of closure stress, temperature, proppant concentration, and flow back rates on fracture conductivity. The objective of performing a dynamic conductivity test is to be able to mimic actual field conditions by pumping fracturing fluid/proppant slurry fluid into a conductivity cell, and applying closure stress afterwards. In addition, a factorial design was implemented in order to determine the main effect of each of the investigated factors and to minimize the number of experimental runs. Due to the stochastic nature of the dynamic conductivity test, each experiment was repeated several times to evaluate the consistency of the results. Experimental results indicate that the increase in closure stress has a detrimental effect on fracture conductivity. This effect can be attributed to the reduction in fracture width as closure stress was increased. Moreover, the formation of channels at low proppant concentration plays a significant role in determining the final conductivity of a fracture. The presence of these channels created an additional flow path for nitrogen, resulting in a significant increase in the conductivity of the fracture. In addition, experiments performed at high temperatures and stresses exhibited a reduction in fracture conductivity. The formation of a polymer cake due to unbroken gel dried up at high temperatures further impeded the propped conductivity. The effect of nitrogen rate was observed to be inversely proportional to fracture conductivity. The significant reduction in fracture conductivity could possibly be due to the effect of polymer dehydration at higher flow rates and temperatures. However, there is no certainty from experimental results that this conductivity reduction is an effect that occurs in real fractures or whether it is an effect that is only significant in laboratory conditions. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148364

Author: Fivman Marpaung
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
The key to producing gas from tight gas reservoirs is to create a long, highly conductive flow path, via the placement of a hydraulic fracture, to stimulate flow from the reservoir to the wellbore. Viscous fluid is used to transport proppant into the fracture. However, these same viscous fluids need to break to a thin fluid after the treatment is over so that the fracture fluid can be cleaned up. In shallower, lower temperature (less than 250°F) reservoirs, the choice of a fracture fluid is very critical to the success of the treatment. Current hydraulic fracturing methods in unconventional tight gas reservoirs have been developed largely through ad-hoc application of low-cost water fracs, with little optimization of the process. It seems clear that some of the standard tests and models are missing some of the physics of the fracturing process in low-permeability environments. A series of the extensive laboratory "dynamic fracture conductivity" tests have been conducted. Dynamic fracture conductivity is created when proppant slurry is pumped into a hydraulic fracture in low permeability rock. Unlike conventional fracture conductivity tests in which proppant is loaded into the fracture artificially, we pump proppant/ fracturing fluid slurries into a fracture cell, dynamically placing the proppant just as it occurs in the field. Test results indicate that increasing gel concentration decreases retained fracture conductivity for a constant gas flow rate and decreasing gas flow rate decreases retained fracture conductivity. Without breaker, the damaging effect of viscous hydraulic fracturing fluids on the conductivity of proppant packs is significant at temperature of 150°F. Static conductivity testing results in higher retained fracture conductivity when compared to dynamic conductivity testing.

Author: Faisal Mehmood
Publisher: Cuvillier Verlag
ISBN: 3736964722
Category : Technology & Engineering
Languages : en
Pages : 160

View

Book Description
Due to the finite nature of petroleum resources and depletion of conventional reservoirs, the exploitation of unconventional resources has been a key to meeting world energy needs. Natural gas, a cleaner fossil fuel compared to oil and coal, has an increasing role in the energy mix. It is expected that the peak global natural gas production will remain between 3.7-6.1 trillion m3 per year between 2019 and 2060. Therefore, addressing the technical challenges posed by reservoir exploitation technologies in an environmentally responsible manner is critical for efficient energy production and energy secure of the world.

Author: Congrui Jin
Publisher: Springer
ISBN: 3319401246
Category : Technology & Engineering
Languages : en
Pages : 522

View

Book Description
This contributed volume presents a multi-perspective collection of the latest research findings on oil and gas exploration and imparts insight that can greatly assist in understanding field behavior, design of test programs, and design of field operations. With this book, engineers also gain a powerful guide to the most commonly used numerical simulation methods that aid in reservoir modelling. In addition, the contributors explore development of technologies that allow for cost effective oil and gas exploration while minimizing the impact on our water resources, surface and groundwater aquifers, geological stability of impacted areas, air quality, and infrastructure assets such as roads, pipelines, water, and wastewater networks. Easy to understand, the book identifies equipment and procedural problems inherent to oil and gas operations and provides systematic approaches for solving them.

Author: Hedong Sun
Publisher: Gulf Professional Publishing
ISBN: 012818325X
Category : Science
Languages : en
Pages : 367

View

Book Description
Dynamic Description Technology of Fractured Vuggy Carbonate Gas Reservoirs delivers a critical reference to reservoir and production engineers on the basic characteristics of fractured vuggy gas reservoirs, combining both static and dynamic data to improve reservoir characterization accuracy and development. Based on the full lifecycle of well testing and advanced production decline analysis, this reference also details how to apply reservoir dynamic evaluation and reserve estimation and performance forecasting. Offering one collective location for the latest research on fractured gas reservoirs, this reference also covers physical models, analysis examples, and processes, 3D numerical well test technology, and deconvolution technology of production decline analysis. Packed with many calculation examples and more than 100 case studies, this book gives engineers a strong tool to further exploit these complex assets. Presents advanced knowledge in well test and production decline analysis, along with performance forecasting that is specific to fractured vuggy carbonate gas reservoirs Helps readers understand the characteristics, advantages, disadvantages and current limitations in technology of fractured vuggy carbonate gas reservoirs Provides a bridge from theory to practice by combining static and dynamic data to form more accurate real-world analysis and modeling

Author:
Publisher:
ISBN:
Category : Fossil fuels
Languages : en
Pages : 680

View

Book Description

Author: Elyezer P. Lolon
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
Low-permeability gas wells often produce less than predicted after a fracture treatment. One of the reasons for this is that fracture lengths calculated after stimulation are often less than designed lengths. While actual fracture lengths may be shorter due to fracture growth out of zone, improper proppant settling, or proppant flowback, short calculated fracture lengths can also result from incorrect analysis techniques. It is known that fracturing fluid that remains in the fracture and formation after a hydraulic fracture treatment can decrease the productivity of a gas well by reducing the relative permeability to gas in the region invaded by this fluid. However, the relationships between fracture fluid cleanup, effective fracture length, and well productivity are not fully understood. In this work I used reservoir simulation to determine the relationship between fracture conductivity, fracture fluid production, effective fracture length, and well productivity. I simulated water saturation and pressure profiles around a propped fracture, tracked gas production along the length of the propped fracture, and quantified the effective fracture length (i.e., the fracture length under single-phase flow conditions that gives similar performance as for multiphase flow conditions), the "cleanup" fracture length (i.e., the fracture length corresponding to 90% cumulative gas flow rate into the fracture), and the"apparent" fracture length (i.e., the fracture length where the ratio of multiphase to single-phase gas entry rate profiles is unity). This study shows that the proppant pack is generally cleaned up and the cleanup lengths are close to designed lengths in relatively short times. Although gas is entering along entire fracture, fracturing fluid remains in the formation near the fracture. The water saturation distribution affects the gas entry rate profile, which determines the effective fracture length. Subtle changes in the gas rate entry profile can result in significant changes in effective fracture length. The results I derived from this work are consistent with prior work, namely that greater fracture conductivity results in more effective well cleanup and longer effective fracture lengths versus time. This study provides better explanation of mechanisms that affect fracturing fluid cleanup, effective fracture length, and well productivity than previous work.

Author: Potcharaporn Pongthunya
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
One of the most critical parameters in the success of a hydraulic fracturing treatment is to have sufficiently high fracture conductivity. Unbroken polymers can cause permeability impairment in the proppant pack and/or in the matrix along the fracture face. The objectives of this research project were to design and set up an experimental apparatus for dynamic fracture conductivity testing and to create a fracture conductivity test workflow standard. This entirely new dynamic fracture conductivity measurement will be used to perform extensive experiments to study fracturing fluid cleanup characteristics and investigate damage resulting from unbroken polymer gel in the proppant pack. The dynamic fracture conductivity experiment comprises two parts: pumping fracturing fluid into the cell and measuring proppant pack conductivity. I carefully designed the hydraulic fracturing laboratory to provide appropriate scaling of the field conditions experimentally. The specifications for each apparatus were carefully considered with flexibility for further studies and the capability of each apparatus was defined. I generated comprehensive experimental procedures for each experiment stage. By following the procedure, the experiment can run smoothly. Most of dry runs and experiments performed with sandstone were successful.

Author: Murtadha Jawad Al Tammar
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

View

Book Description
Pursuit of unconventional gas and oil has prompted the development and adoption of innovative fracturing solutions. Energized fracturing is one promising technology that can be an effective alternative to mainstream slickwater or hybrid fracturing fluids in many applications. Yet, field use of energized fluids accounted for only 2-3% of 2011-2012 reported fracturing treatments in the U.S. compared to a markedly higher share of 42-46% in Canada. Recently, the superior performance and economics of foams were reported in the Montney Gas Formation in western Canada. In this thesis, we utilized field data and a compositional, 3D fracturing simulator to showcase the production performance of energized fluids in several areas of the Cardium and Bakken Light Oil Formations within the Western Canadian Sedimentary Basin. Average well data in the Cardium revealed better production results for foam compared to nitrified slickwater in the West Willesden Green and Buck Lake-Wilson Creek fields. Foams had a 110% higher initial peak production rate and 51% higher long term cumulative production in the West Willesden Green field with a similar initial production profile and a 16.2% higher long-term production in the Buck Lake-Wilson Creek fields. In contrast, the initial peak production rate of nitrified slickwater was 28% higher with 95% incremental oil production relative to foam in the West Pembina field. This shows that the effectiveness of foam fracturing fluids can vary significantly perhaps because of better fracture containment and lower rock water sensitivity in some fields. Across all the areas studied, foam completions on average were found to have 5-20% lower costs and lower water and proppant requirements by 72-87% and 7-38%, respectively. Fracture modeling, on the other hand, showed 53% higher well productivity increase using nitrified slickwater largely because of better contained fractures in the thin Cardium reservoir interval. Nitrified slickwater had twice the propped fracture length and conductivity of foam. With markedly improved fracture containment in depleted Cardium wells, foam is likely to outperform nitrified slickwater as fracturing fluid recovery is enhanced and permeability/relative permeability damage is reduced in water sensitive areas. In the Bakken Formation, field data showed an average of 15.8% higher long term cumulative production for foam compared to crosslinked gel despite the higher initial rate of crosslinked gel. Foam fractures were predicted to have 44% higher well productivity increase than crosslinked gel fractures based on simulations conducted. Foam had 50% longer propped fracture, 73% higher fracture conductivity, and twice the relative permeability to oil in the invaded zone compared to crosslinked gel. In our simulation, some factors were not accounted for such as formation heterogeneity, the effect of solution gas drive and associated water production, and the interaction between induced and natural fractures. Also, our modeling work was based on generic and synthesized data. For more accurate comparisons, we recommend performing simulation runs with detailed well-specific data.