| After production stage of the basic pattern, the primary infilling, the secondary infilling, the tertiary infilling and polymer flooding, three major reservoirs, Lamadian, Saertu and Xingshugang in Daqing Oilfield, have been entering in the later stage of high water cut. Through the adjustments of several well patterns, reservoir pressure has been constantly changed, which leads to a multiple pressure layer system and a complex underground environment where high pressure layer and low one alternately distribute vertically, and badly influences drilling and completion.In this paper, pressure profile adjustment technique for multi-layer and multiple pressure system reservoir in adjustment well drilling block during the process of drilling is studied. A calculating model of reservoir pressure under injection and production is established. Pressure stabilization time of injection well, a method for the forecasting of pressure stabilization in wellhead, and a method for the forecasting of reservoir pressure, using stable pressure in wellhead of injection well and identification technique of fluid invasion in wellbore, are given, respectively. The effect of fluid outlet and pressure blowdown in injection well and that of water injection holding pressure are analyzed. Therefore, a pressure profile adjustment technique according to different pressure profile behaviors is presented.The result of field application test shows that the presented technique in this paper is applicable to the pressure profile adjustment of multi-layer and multiple pressure system in in adjustment well drilling block during the process of drilling, and to the diminishing of pressure difference among layers and in annulus as well, so that reservoir can be protected and a stable underground environment provided to improve the cementing quality of adjustment well. The whole study is applicable to the drilling of tertiary infilling adjustment wells in Daqing Oilfield.
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