Fall-Off Test Analysis and Transient Pressure Behavior in Foam Flooding

Gargar, N. Khoshnevis; Mahani, Hassan; Rehling, Johannes; Vincent-Bonnieu, S.; Farajzadeh, R.

doi:10.3997/2214-4609.201412119

Cited by 4 publications

(1 citation statement)

References 69 publications

(60 reference statements)

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“…Fall-off testing is an effective method for monitoring water or foam injection. Typically, fall-off tests are conducted by ceasing the injection and analyzing the transient pressure to assess any mobility changes near the injector [15]. In such tests, bottom-hole pressures are recorded at the injection well, and the data are used to examine the reservoir mobility changes caused by the injection.…”

Section: Pressure Testing For Foam Monitoringmentioning

confidence: 99%

Pressure Measurements for Monitoring CO2 Foam Pilots

et al. 2022

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This study focuses on the use of pressure measurements to monitor the effectiveness of foam as a CO2 mobility control agent in oil-producing reservoirs. When it is applied optimally, foam has excellent potential to improve reservoir sweep efficiency, as well as CO2 utilization and storage, during CO2 Enhanced Oil Recovery (EOR) processes. In this study, we present part of an integrated and novel workflow involving laboratory measurements, reservoir modeling and monitoring. Using the recorded bottom-hole pressure data from a CO2 foam pilot study, we demonstrate how transient pressures could be used to monitor CO2 foam development inside the reservoir. Results from a recent CO2 foam pilot study in a heterogeneous carbonate field in Permian Basin, USA, are presented. The injection pressure was used to evaluate the development of foam during various foam injection cycles. A high-resolution radial simulator was utilized to study the effect of foam on well injectivity, as well as on CO2 mobility in the reservoir during the surfactant-alternating gas (SAG) process. Transient analysis indicated constant temperature behavior during all SAG cycles. On the other hand, differential pressures consistently increased during the surfactant injection and decreased during the subsequent CO2 injection periods. Pressure buildup during the periods of surfactant injection indicated the development of a reduced mobility zone in the reservoir. The radial model proved to be useful to assess the reservoir foam strength during this pilot study. Transient analysis revealed that the differential pressures during the SAG cycles were higher than the pressures observed during the water-alternating gas (WAG) cycle which, in turn, showed foam generation and reduced CO2 mobility in the reservoir. Although pressure data are a powerful indicator of foam strength, additional measurements may be required to describe the complex physics of in situ foam generation. In this pilot study, it appeared that the reservoir foam strength was weaker than that expected in the laboratory.

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Section: Pressure Testing For Foam Monitoringmentioning

confidence: 99%

Pressure Measurements for Monitoring CO2 Foam Pilots

et al. 2022

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Optimization of CO2-Foam Injection through Resistivity and Pressure Measurements

Karakas

Aminzadeh

2018

SPE Western Regional Meeting

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This paper focuses on the use of combined resistivity and pressure measurements to determine the effectiveness of foam as a mobility control method and presents a theoretical framework to describe the expected resistivity changes during CO2-Foam displacements. With this objective, we first provide equations to estimate the resistivity for CO2-Foam systems and then utilize Population Based (PBE) and Steady-State Foam models to quantify these effects. Using analytical solutions based on the fractional flow theory, we present the corresponding resistivity and mobility distributions for both ideal and non-ideal reservoir displacement scenarios. Additionally, assuming pressure measurements only, we examine the inter-dependency between various foam parameters. Our results suggest that combination of Pressure and Resistivity measurements in time-lapse mode could be deployed as an effective monitoring tool in field applications of the (CO2) Foam processes. The proposed method is novel as it could be employed to predict under-performing CO2-Foam floods as well as improve oil recovery and CO2 storage.

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First Pilot Design of Low-Tension-Gas (LTG) Flooding in Carbonate Field in North Oman

Al-Abri,

Mahruqi,

Al- Aamri

et al. 2023

Day 3 Wed, October 04, 2023

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Field X is a medium-large low-permeability carbonate field situated in the Northern part of Oman that is in a mature waterflood stage. Low-Tension-Gas (LTG) flooding was identified as a promising EOR technology to improve oil recovery, since it screened technically and commercially for a low permeability (<10 mD), high formation water salinity (>200,000 ppm and hardness 19,000 ppm) and relatively shallow depth (1200 m) condition. Experimental studies in Field X cores have shown that LTG flooding can improve oil recovery by combining two effects: reducing the interfacial tension (IFT) between oil and water; and controlling mobility through the formation of in-situ foam with an injected gas. This paper presents the design of the first field trail for integrating the foam technology and water-alternating-gas (WAG) injection into the mature water flood in Field X. To de-risk the various elements of LTG technology and evaluate its feasibility and potential, a phased strategy was developed. The first phase of the strategy focuses on testing the foaming surfactant and confirming if foam can be generated inside the reservoir. it involves piloting the foam generation through WAG injection to establish baseline followed by surfactant alternating gas (SAG). A hybrid approach based on numerical modeling and experimental data was used to design the optimum slugs of WAG an SAG. A comprehensive surveillance program was designed to evaluate the response of foam generation inside the reservoir. The program includes monitoring pressure responses, estimating saturation profiles and evaluating gas conformance improvement due to foam generation. The injection scheme consists of 5 cycles of immiscible WAG to establish a baseline followed by 10 cycles of Surfactant Alternating Gas (SAG) to generate foam. Based on model evaluations we expect that the trend in bottom hole pressure during SAG over WAG should be observable (> 10%) due to foam generation in the reservoir. The logging program is designed to confirm the divergence of flow from higher permeability to lower permeability zones. The results also might show a reduction in remaining oil saturation due to gas conformance improvements because of foam generation. The results of the pilot tests will be used to evaluate the feasibility of LTG flooding for low- permeability, high salinity carbonate reservoirs in Oman. The data obtained will be critical to identify the potential benefits and challenges of shifting from a water-based flooding to a staircase of introducing gas, WAG, SAG (foam) and LTG flooding and guide further design and implementation of full-scale LTG flooding projects in similar reservoirs.

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Fall-Off Test Analysis and Transient Pressure Behavior in Foam Flooding

Cited by 4 publications

References 69 publications

Pressure Measurements for Monitoring CO2 Foam Pilots

Pressure Measurements for Monitoring CO2 Foam Pilots

Optimization of CO2-Foam Injection through Resistivity and Pressure Measurements

First Pilot Design of Low-Tension-Gas (LTG) Flooding in Carbonate Field in North Oman

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