We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
压裂液滤失对裂缝萌生及动态闭合过程的影响机理.
- Authors
周 彤; 王海波; 李凤霞; 何 柏; 周 涛; 李 宁
- Abstract
Hydraulic fracturing technology has become one of the main measures for the development of tight oil and gas reservoirs. At present, however, the dynamic fracture closure laws in the process of reservoir stimulation are not understood deeply, so the research theory of fracture formation mechanism can hardly meet the needs of the actual production. In order to increase the complexity of fracture networks and connect more reservoir spaces, this paper establishes different filtration behavior models from the perspective of fracturing fluid viscosity and basic reservoir physical properties based on pseudo triaxial experiments. Then, the idea of controlling fracturing fluid viscosity according to actual reservoir physical property is put forward. Finally, the influence of filtration behavior on fracture initiation mechanism is clarified, and the dynamic closure laws are revealed. And the following research results are obtained. First, with the increase of radial stress, the peak fracturing strength and axial strain of the rock sample increase, i.e., obvious strain softening characteristics occur, which results in higher critical reservoir fracturing pressure. Second, the filtration system formed during hydraulic fracturing due to fracturing fluid viscosity and basic reservoir physical properties is one of the main reasons for the differences in fracture initiation mechanisms and dynamic closure laws. Third, the medium filtration system of shale-low viscosity fracturing fluid can easily open the weak bedding surface, leading to secondary fracturing. The fracture width curve is bimodal, and the closure degree is 38%- 71%. The shale-high viscosity fracturing fluid system has a lower filtration degree, so the fracture is only slightly closed after opening, and the fracture width curve is platform-shaped. The filtration degree of sandstone-high viscosity fracturing fluid system is higher, so the fracturing fluid presents filtration behavior rapidly on the wall after fracture opening. As a result, the injection pressure drops quickly, and the secondary fracturing conditions can be hardly satisfied. The fracture width curve is unimodal, and the closure degree is 47%-94%. In conclusion, it is necessary to consider overburden pressure and control fracturing fluid viscosity based on the actual basic reservoir physical properties in the process of field fracturing, so as to form a more complex fracture network. The research results can provide technological guidance for the formulation of field fracturing scheme of tight oil and gas reservoir and the oil and gas stimulation.
- Subjects
FRACTURING fluids; GAS reservoirs; RADIAL stresses; PETROLEUM reservoirs; HYDRAULIC fracturing; GAS condensate reservoirs; SHALE oils
- Publication
Natural Gas Industry, 2023, Vol 43, Issue 3, p91
- ISSN
1000-0976
- Publication type
Article
- DOI
10.3787/j.issn.1000-0976.2023.03.009