Characteristics analysis and effectiveness evaluation of structural fractures are of great significance to predict favorable tight sandstone reservoir and to select development strategy in Keshen-8 gas pool

Kuqa Depression

Tarim Basin.We analyzed the basic characteristics and forming sequence of the structural fractures

and the factors influencing their growth through such data as core

image logging and single well productivity.In the end

the planar and vertical effectiveness of structural fractures was evaluated

and some suggestions for development were given.The results show that (1) the structural fractures

partly filled with anhydrites

dolomites and seepage sand particles

are mainly upright or have a high dip angle.The third-phase structural fractures developed during the deposition of the Pliocene Kuqa Formation are the most important ones for gas preservation in Keshen-8 gas pool.(2) Faults

lithology

stratum thickness and sedimentary microfacies function to control the development of structural fractures.Structural fractures on the upper part of anticline are highly effective

but their effectiveness would decrease dramatically when their dominant orientation intersects with the direction of present maximum principal stress at a large angle.(3) The controlling effect of unconformity on structural fracture effectiveness is limited within 70 m to the unconformity.The Bashijiqike Formation reservoirs in Keshen-8 gas pool should be produced primarily through hydraulic fracturing

and top priority should be given to the 3

rd

sand unit in development

followed by the 4

th

sand unit and its underlying reservoirs

and the 1

st

and 2

nd

sand units being the last ones.