An efficient fracturing and packing sand control string for fine layer division

To solve the obvious technical difficulties in the well completion operation of Ø244.5 mm casing, such as the adjustment of interlayer isolation and the fine division of thin oil layer, this paper designed an outer sand control string which integrates bypass overflow screen and production sliding sleeve and preset the packing and conversion assembly into the fracturing and packing sand control service string with sealing assembly, so that the number of central pipes to run in the hole during the packing is reduced by one layer while the needs of low-friction and large-displacement packing sand control and fine layer division are satisfied. The analysis of key string tools and the simulation of construction parameters indicate that the maximum tensile load to ensure the safe running of this string is 50 kN. When the length of the wash pipe is 500 m and the construction displacement of positive-circulation fracturing and packing is 6.48 m³/min, the maximum pressure is 58.3 MPa; when the construction displacement of reverse-circulation flushing is 1.27 m³/min, the maximum pressure is 17.45 MPa, which satisfy the requirements of field construction. This technology is applied in Well A of Bohai Oilfield to perform one five-layer packing sand control operation. The field application results indicate that the efficient fracturing and packing sand control string for fine layer division has stable and reliable performance and its operation time is 3 d shorter than that of conventional packing sand control operation. What’s more, it can realize separate-layer production control without running separate-layer production string in the hole, so as to save the operation time by about 1 d. Obviously, it has a certain value of popularization and application.