LAPSE:2024.0506
Published Article
LAPSE:2024.0506
Effect of Acid-Injection Mode on Conductivity for Acid-Fracturing Stimulation in Ultra-Deep Tight Carbonate Reservoirs
June 5, 2024
Abstract
The conductivity of acid-etched fractures and the subsequent production response are influenced by the injection mode of the fracturing fluid and acid fluid during acid fracturing in a carbonate reservoir. However, there has been a lack of comprehensive and systematic experimental research on the impact of commonly used injection modes in oilfields on conductivity, which directly affects the optimal selection of acid-fracturing injection modes. To address this gap, the present study focuses on underground rock samples, acid systems, and fracturing fluid obtained from ultra-deep carbonate reservoirs in the Fuman Oilfield. Experimental investigations were conducted to examine the conductivity of hydraulic fractures etched by various types of acid fluids under five different injection modes: fracturing fluid + self-generating acid or cross-linked acid; fracturing fluid + self-generating acid + cross-linked acid. The findings demonstrate that the implementation of multi-stage alternating acid injection results in the formation of communication channels, vugular pore space, and natural micro-cracks, as well as grooves and fish-scales due to enhanced etching effects. The elevation change, amount of dissolved rock, and conductivity exhibited by rock plates are significantly higher in comparison to those achieved through the single-acid injection mode while maintaining superior conductivity. It is recommended for optimal conductivity and retention rate in the Fuman Oilfield to adopt two stages of alternating acid-fracturing injection mode. Field application demonstrated that two-stages of alternating acid-fracturing generate more pronounced production response than the adjacent wells.
The conductivity of acid-etched fractures and the subsequent production response are influenced by the injection mode of the fracturing fluid and acid fluid during acid fracturing in a carbonate reservoir. However, there has been a lack of comprehensive and systematic experimental research on the impact of commonly used injection modes in oilfields on conductivity, which directly affects the optimal selection of acid-fracturing injection modes. To address this gap, the present study focuses on underground rock samples, acid systems, and fracturing fluid obtained from ultra-deep carbonate reservoirs in the Fuman Oilfield. Experimental investigations were conducted to examine the conductivity of hydraulic fractures etched by various types of acid fluids under five different injection modes: fracturing fluid + self-generating acid or cross-linked acid; fracturing fluid + self-generating acid + cross-linked acid. The findings demonstrate that the implementation of multi-stage alternating acid injection results in the formation of communication channels, vugular pore space, and natural micro-cracks, as well as grooves and fish-scales due to enhanced etching effects. The elevation change, amount of dissolved rock, and conductivity exhibited by rock plates are significantly higher in comparison to those achieved through the single-acid injection mode while maintaining superior conductivity. It is recommended for optimal conductivity and retention rate in the Fuman Oilfield to adopt two stages of alternating acid-fracturing injection mode. Field application demonstrated that two-stages of alternating acid-fracturing generate more pronounced production response than the adjacent wells.
Record ID
Keywords
acid-fracture morphology, acid-injection mode, conductivity, field application, multi-stages alternating acid fracturing, ultra-deep carbonate reservoirs
Subject
Suggested Citation
Liu J, Ren D, Feng S, Liu J, Qin S, Qiao X, Gou B. Effect of Acid-Injection Mode on Conductivity for Acid-Fracturing Stimulation in Ultra-Deep Tight Carbonate Reservoirs. (2024). LAPSE:2024.0506
Author Affiliations
Liu J: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Ren D: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Feng S: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Liu J: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Qin S: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Qiao X: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Gou B: National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China [ORCID]
Ren D: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Feng S: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Liu J: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Qin S: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Qiao X: Oil and Gas Engineering Research Institute, Tarim Oilfield Company, PetroChina, Korla 841000, China; R&D Center for Ultra Deep Complex Reservoir Exploration and Development, CNPC, Korla 841000, China; Engineering Research Center for Ultra-Deep Complex Oil
Gou B: National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China [ORCID]
Journal Name
Processes
Volume
12
Issue
4
First Page
651
Year
2024
Publication Date
2024-03-25
ISSN
2227-9717
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PII: pr12040651, Publication Type: Journal Article
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LAPSE:2024.0506
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https://doi.org/10.3390/pr12040651
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Jun 5, 2024
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