Abstract:

Complicated geologic characteristics and special flow mechanism of tight sand gas reservoirs make a lot of reserves difficult to be developed.The exploitation of difficulttoproduce reserves is an important subject.In this paper，based on a lot experiment，the flow mechanism of tight sand gas reservoirs of Js¹₂ and Js³₂ in Xinchang gas field are studied，and the factors influencing the exploitation of difficulttoproduce reserves are analyzed.Accordingly，corresponding development strategies are put forward.As a result，water lock，stress sensitivity and threshold pressure effect are main influencing factors as to difficulttoproduce reserves.The present production pressure difference is 10MPa，much higher than reasonable pressure difference 7MPa，which results in severe stress sensitivity damage.Massive hydraulic fracturing technology with low harmful and high fracturing fluid back flow technology，multilayer fracturing technology and horizontal well technology are main exploitation strategies as to difficulttoproduce reserves in Xinchang Js₂¹、Js₂³ gas reservoir.

Key words: tight sand gas reservoirs, difficulttoproduce reserves, massive hydraulic fracturing, multilayer fracturing, horizontal well technology