Design and Application of Removable Plugging Slurry for Fractured Carbonate Reservoir
To meet the requirements of leakage stopping and reservoir protection at the same time in fractured formation, the removable plugging slurries with high temperature tolerance were designed, evaluated and applied in the field successfully. Analysis shows that the fibre materials can deposit onto crack surface, bridge and seal fractures quickly and the selected particles can bridge in throat near wellbore. The comprehensive grading of filling particles was determined from the point of view of gradient filling. The designed plugging slurries KJD155 and KJD200 with higher total dissolution rates sealed 1 mm, 2 mm, 3 mm, and 4 mm crack blocks effectively at room temperature and high temperature (KJD155 at 155 °C; KJD200 at 200 °C) respectively. Their pressure bearing ability of them was up to 5 MPa under bottom hole conditions, which was beneficial to the next operation. Field application of the designed plugging slurries was carried out successfully and showed that they were removable and did smaller damage to reservoir.
A New Fuzzy Ball Working Fluid for Plugging Lost Circulation Paths in Depleted Reservoirs
Abstract Lost circulation is a serious problem. A new fuzzy ball working fluid was developed by using SDS, SDBS, PAC, HES, and PAM. Ball-type stuff that has an air pocket inside and fluff outside can be identified in the fluid, which was termed by the authors the fuzzy ball. The engineering properties of the fuzzy ball working fluid show that it can meet working requirements. Plugging experiments confirm the capability of automatically plugging different sizes lost paths. Thus, the working fluid can be used for both traditional operations and lost circulation prevention. It has been applied in more than 10 wells in China.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.