Determination of temperatures for cementing in wells drilled in deep water

摘要

The American Petroleum Institute (API), Sub-committee 10 (Well Cements) has developed temperature correlations for estimating circulating temperatures for cementing. These correlations use the true vertical depth and a single temperature gradient (computed from the bottomhole static temperature) to make the estimation. Often wells have temperture transitions meaning that three is a change in temperature gradient below a transition zone. Wells drilled below bodies of water likewise have a temperature transitionin the form of the change from water to earthen formations. This can be relatively insignificant, except in the case of large water depths (generally considered to be 1500 ft or more). Such environments are currently being drilled in the U.S.Gulf Coast, Northern Europe, Afirca, Brazil, Middle East and Far East. At such water depths, a compounding problem is that the water temperature decreases, approaching the freezing point of water at great depths. It is not uncommon in these areas that the temperature at the mudline or seabed is 40 deg-F or less. Not only is the water temperature low, but formations close below the seafloor are cold also.