Evaluation of Damage Mechanisms and Skin Factor in Tight Gas Reservoirs

Bahrami, Hassan; Rezaee, Mohammad; Ostojic, Jakov; Nazhat, Delair; Clennell, Ben

doi:10.2118/142284-ms

Cited by 11 publications

(5 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This pressure difference causes the solid particles in drilling fluids (barite and clay) to enter easily into the formations, thus plugging the pore throats. 82 Also, severe plugging of pore throat can occur due to invasion of mud filtrate into the formation. 83,84 This causes an increase in the gas and oil flow resistance.…”

Section: Sc-co 2 -Based Drillingmentioning

confidence: 99%

“…Moreover, as explained earlier, when water-based drilling fluids were used to exploit unconventional shale reservoirs, an overbalanced condition occurs at the bottom hole. This pressure difference causes the solid particles in drilling fluids (barite and clay) to enter easily into the formations, thus plugging the pore throats . Also, severe plugging of pore throat can occur due to invasion of mud filtrate into the formation. , This causes an increase in the gas and oil flow resistance.…”

Section: Sc-co2-based Drillingmentioning

confidence: 99%

See 1 more Smart Citation

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

et al. 2022

View full text Add to dashboard Cite

Hydraulic fracturing has transformed the international energy landscape by becoming the go-to method for the exploitation of natural gas from unconventional shale reservoirs. However, in the recent years, the search for an alternative method of shale-gas exploration has intensified, because of various problems (e.g., contamination of ground and surface water, overexploitation of precious water resources, air pollution, etc.) associated with the usage of water-based fracturing techniques. The use of CO2 for shale gas exploitation has emerged as a better alternative to aqueous-based gas exploration techniques. CO2 when injected into deep shale reservoirs, transitions into supercritical CO2 (SC-CO2) when temperature and pressure condition exceeds the critical point, i.e., 31.1 °C and 7.38 MPa. In this paper, we comprehensively review the impact of SC-CO2 on shale gas reservoirs during the different stages of shale-gas exploration, i.e., (i) drilling, which involves the superiority of SC-CO2 over water-based drilling fluids, in terms of achieving under-balanced well condition, higher rates of penetration, and resistance to formation damage; (ii) fracturing, which involves factors affecting the tortuosity of fractures created by SC-CO2 fracturing, breakdown pressure, and proppant-carrying capacity; and (iii) injection, which involves the twin-headed benefit of enhanced recovery due to CO2/CH4 competitive adsorption and geological sequestration, CO2 vs CH4 excess sorption as a function of pressure, etc. Several research works have indicated discrepancies on how SC-CO2 impacts different shale properties. Some studies show low-pressure N2-gas-adsorption-derived surface area and total pore volume to be increasing with SC-CO2 imbibition, while others show a decreasing trend for the same. Similarly, for some shales, the quartz content, along with the clay mineral contents, decreased as the exposure to SC-CO2 increased, while in some other studies, with similar long-term exposure to SC-CO2, the quartz content was observed to increase along with the decrease in clay content and vice versa. Essentially, the increased exposure to SC-CO2 results in the dissolution of primary porous structures and fractures, and reformation of newer porous structure and conduits in shales. Nonetheless, these changes in the mineralogy weaken the microstructure of the rock bringing significant changes in the mechanical properties of the shales with implications on the wellbore stability and fracturing efficiency. The mechanical properties such as uniaxial compressive strength (UCS), Young’s modulus, and tensile strength decrease as the SC-CO2 saturation period increases. However, some studies have shown factors like bedding angle and phase-state of CO2 having varying effect on the strength behavior of the shales. Moreover, changes in the structure of shales caused by the creation of fractures and the reduction of their strength can also pose major risks, because of potential leakage of CO2 through these created pathways. How these processes would i...

show abstract

Section: Sc-co 2 -Based Drillingmentioning

confidence: 99%

Section: Sc-co2-based Drillingmentioning

confidence: 99%

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

et al. 2022

View full text Add to dashboard Cite

show abstract

“…3.14, they indicate that open-hole completion in the gas wells with large wellbore breakouts can provide significantly higher initial gas production rate compared with cased-hole completion system. In use of open-hole completion, the enlarged wellbore due to break outs can result in higher effective wellbore radius, and therefore a lower skin factor and higher productivity [3]. …”

Section: Wellbore Breakoutsmentioning

confidence: 99%

Tight Gas Reservoir Simulation

Bahrami

2013

Evaluating Factors Controlling Damage and Productivity in Tight Gas Reservoirs

View full text Add to dashboard Cite

Analytical and numerical simulation studies are performed to have a qualitative understanding of damage mechanisms associated with production from non-fractured and hydraulically fractured tight gas reservoirs; and evaluate its potential impact on well productivity.In building tight gas reservoirs simulation model, it is important to use a consistent set of field data in order to get meaningful simulation outputs. Based on a West Australian tight gas field data, the simulation models are built at reservoir scale and core scale. In this chapter, reservoir simulation studies for different types of well and tight reservoirs are presented. Effect of Damage Mechanisms on Well ProductivityReservoir simulation is used to understand how damage mechanisms are controlled by the well and reservoir parameters such as reservoir permeability, permeability of the damaged zone, radius of the damaged zone, drilling fluid type, capillary pressure and relative permeability curves.In this section, the effects of different parameters on damage and skin factor are studied using the reservoir simulation models. To evaluate the damage effects, the term flow efficiency (FE) is used in some of the cases, which is defined as the ratio of the pressure drop across the model in the case of zero skin virgin homogeneous rock; to the pressure drop in the case of perforated and/or damaged rock (FE equals to 1 in the case that there is no damage introduced to a non-perforated model). Damaged Zone Permeability and RadiusThe simulation model is run for conventional and tight cores, with damaged zone permeability of K d and damaged zone radius of r d . The model results are shown in N. Bahrami, Evaluating Factors Controlling Damage and Productivity in Tight Gas Reservoirs, Springer Theses,

show abstract

“…On the other hand, perforation completion provides a direct pathway for fluid flow, enabling it to penetrate beyond the zone of drilling damage. However, a crushed zone may contribute to over half of the additional damage [37]. Thus, the question of whether slotted liner or perforation completion is better suited for UGS horizontal wells remains to be answered.…”

Section: Introductionmentioning

confidence: 99%

Gas Injection Capacity of Slotted Liner and Perforation Completion in Underground Natural Gas Storage Reservoirs

Wang¹,

Dai

Xie³

et al. 2023

Processes

View full text Add to dashboard Cite

The use of Horizontal wells is a common method of underground natural gas storage (UGS), but there is still a need to discuss whether they are more suitable for slotted liner or perforation completions. To address this issue, a numerical model is developed to predict the gas injection rate of horizontal wells while considering the skin factor. Here, a novel uncoupled iteration method is employed to determine the skin factor deriving from turbulence in each time step when the bottom hole pressure is fixed. The uncoupled method begins with an estimate of the initial gas injection rate, which is then used to calculate a turbulent skin factor. This turbulent skin factor is then used to update the gas injection rate, iterating continuously until convergence is achieved. The effects of slotted liner and perforation design parameters, formation damage, and injection pressure on the skin factor are analyzed. The main findings suggest that the error in the gas injection rate calculated by the non-coupled model compared with the coupled model is only 0.6%, yet it can reduce the number of sub-iterations to 1/10 of that required by the coupled model. Moreover, the uncoupled model can provide results within four steps, even when the convergence condition is 10−14. The open area and perforation density play a significant role in determining the connection degree between the horizontal well and the reservoir, with a larger perforation density resulting in a negative skin factor. Perforations are more suitable than slotted liners for reservoirs with severe formation damage, and the difference in skin factor between the two can reach a value of 40.87 when the ratio of the damage zone’s permeability to that of the normal reservoir zone is 0.05. It is easier to reduce turbulence damage in slotted liner completions than perforation completions, with the turbulence damage of the slotted liner being only 15.9% of that of the perforation. However, to avoid damage it is crucial to prevent the screen tube from being plugged in, as it might otherwise rise to three to ten times the original level. This study provides a theoretical basis and practical reference for the application of slotted liner and perforation method in UGS horizontal wells.

show abstract

Evaluation of Damage Mechanisms and Skin Factor in Tight Gas Reservoirs

Cited by 11 publications

References 10 publications

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

Tight Gas Reservoir Simulation

Gas Injection Capacity of Slotted Liner and Perforation Completion in Underground Natural Gas Storage Reservoirs

Contact Info

Product

Resources

About

Evaluation of Damage Mechanisms and Skin Factor in Tight Gas Reservoirs

Cited by 11 publications

References 10 publications

Impact of Supercritical CO2 on Shale Reservoirs and Its Implication for CO2 Sequestration

Impact of Supercritical CO2 on Shale Reservoirs and Its Implication for CO2 Sequestration

Tight Gas Reservoir Simulation

Gas Injection Capacity of Slotted Liner and Perforation Completion in Underground Natural Gas Storage Reservoirs

Contact Info

Product

Resources

About

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration