THE IMPACT OF ANNULUS WIDTH ON WELL PERFORMANCE

摘要

The annulus of a well is the area between the exterior of the casing or screen and the interior of the borehole (Figure 1). The casing may be driven or drilled directly into the earth using drilling techniques such as cable tool or dual rotary, but most wells have an annular void that is filled with various materials after the casing and screen have been installed. Various annular materials provide three types of benefits: filtration, sealing, or well stabilization. Filter pack sand is commonly installed adjacent to the well screen to facilitate water production without invasion of native sediments (fine sand and silt) that will damage the pump equipment and clog water distribution systems.