Prospects for the use of acid gel for proppant fracturing of carbonate reservoirs in the Samara region

UDK: 622.276.66.002.34

DOI: 10.24887/0028-2448-2020-8-54-57

Key words: hydraulic fracturing, acid gel, cross-linked acid, carbonate reservoirs fracturing, effect of the carbonates fracturing, proppant fracture acidizing, acid fracturing

Authors: Gen.G. Gilaev (Samaraneftegas JSC, RF, Samara), M.Ya. Khabibullin (Branch of Ufa State Petroleum Technological University in Oktyabrsky, RF, Oktyabrsky), G.G. Gilaev (Kuban State Technological University, RF, Krasnodar)

Oil and gas reserves of the Samara region are dispersed in a wide range of oil and gas deposits with different lithology and age: from the Early Devonian to the Late Permian. According to the lithological composition the reservoirs are represented by terrigenous, carbonate and carbonate-siliceous sediments. In connection with the reduction of the resource base of terrigenous reservoirs and in order to maintain high levels of oil production, for many producing enterprises the urgent task is to increase the efficiency of acid stimulation of carbonate and carbonate-siliceous reservoirs. Conventional acidizing of the near-wellbore area, as well as acid fracturing, often do not lead to the expected increase in production and the duration of the effect. Often, the effect of proppant fracturing is several times longer than under acid fracturing. The reason is, presumably, large fracture half-length. The fracturing fluid (guar crosslinked water-based gel) for proppant hydraulic fracturing is more effective due to its high viscosity and less fluid leakage into the formation. As a result, the fracture is kept open longer. A larger drainage area is obtained, both laterally and vertically, thereby involving in the development the interlayer that were not previously involved before. It is considered that when combining proppant and acid fracturing, the drainage area also increases due to involve of natural fracturing zones with acid fracturing around the fracture created during proppant fracturing. Therefore, the development and industrial implementation of new technologies and methods for stimulating carbonate reservoirs is an important task for oil producing enterprises. One of these technologies is discussed in the article.
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