As the consumption of oil and gas
resources is increasing, secondary
exploitation in old wells and unconventional oil and gas exploitation
methods are becoming increasingly important. As a result of complex
reservoir environments and the reservoir properties, such as ultralow
porosity and permeability, hydraulic fracturing is an important means
to achieve effective recovery. Temporary plugging fracturing is currently
an efficient fracturing technology and is suitable for refracturing
of old wells and multi-stage fracturing in unconventional reservoirs,
which is conducive to constructing complex fracture networks and increasing
production. Recently, in the field of temporary plugging fracturing,
how to design the operation parameters of temporary plugging fracturing
still remains ambiguous and empirical. In this paper, a numerical
simulation study of the liquid–solid two-phase flow of the
temporary plugging agents and the fracturing fluid was conducted using
two physical models: a wellbore flow model and a wellbore–fracture
temporary plugging model. The transport processes of the temporary
plugging agents along with fracturing fluid in a vertical wellbore,
in a horizontal wellbore, and at a fracture position were simulated.
Simulations that coupled computational fluid dynamics and the discrete
element method were used in the simulation process. The effects of
the temporary plugging agent concentration, particle size, particle
size ratio, fracturing fluid rate, and fracturing fluid viscosity
on the migration process of the temporary plugging agent were investigated.
The simulation results show that a higher concentration and viscosity
of a temporary plugging agent help to sustain the flow stability in
the vertical wellbore, while the viscosity and flow rate of the fracturing
fluid have an impact on whether sedimentation of the temporary plugging
agent occurred in the horizontal wellbore. In addition, the particle
size ratio and concentration of the temporary plugging agent are the
key factors for a successful bridging and plugging. For a specific
field application in Longmaxi Formation, Sichuan Province, the operation
parameters of temporary plugging fracturing have been designed and
achieved a successful refracturing treatment.
Successful exploitation of tight sandstone gas is one of the important means to ensure the “increasing reserves and production” of the oil and gas initiative and also one of the important ways to ensure national energy security. To further improve the accuracy of historical matching of field data such as gas production and bottom-hole pressure during the production process of this type of gas reservoir, in this study, a new expression of wellbore pressure for the uniform flow of vertical fractured wells in Laplace space based on the point sink function model of vertical fractures in tight sandstone gas reservoirs is constructed. This innovation is based on a typical production data analysis plot of the Blasingame type that uses the numerical inversion decoupling mathematical equation. After analyzing the pressure and pressure derivative characteristics of each flow stage in the typical curves, a new technique of type-curve matching was proposed. In order to verify the correctness of the model and the application value of the field, based on the previous production data of Sulige Gas Field in China, a new set of production data diagnostic chart of tight sandstone gas reservoir was formed. A case analysis showed that the application of the production data analysis method and data diagnosis plot in the field accurately evaluated the development effect of the tight sandstone gas reservoirs, clarified the scale of effective sand bodies, and provided technical support for optimizing and improving the well pattern and realizing the efficient development of gas fields.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.