英国IWCF井控培训教程2-溢流及井涌Kick.ppt

Abnormal Pressure Thick gas sand Also can cause abnormal pressures. 1 p = 0.465 * 1,300 = 605 psig 2 P = 605 - 0.05 * 300 = 605 - 15 = 590 psig 3 g = 590/1,000 = 0.590 psi/ft EMW = 0.590/0.052 =11.3 ppg Causes of abnormal pressure Origins for the generation of abnormal pressures (after Fertl) Abnormal pressure detection Techniques available To detect abnormally high pressures 英国IWCF井控培训教程-溢流及井涌IWCF Well Control-Causes Warning signs of Kick 中东石油智库 Well Kick Well Kick Is an influx of formation fluids such as oil, gas, or salt water into the wellbore from a formation that has been penetrated by the wellbore. Kick is an unscheduled entry of formation fluid(s) into the wellbore. Well Kick Once a kick occurs, the intruded fluid further reduces the pressure of the mud column. As a result, formation fluid may flow into the wellbore at an increasing rate. Why does a kick occur? So, a well kick should be stopped or controlled as soon as possible. Well Kick The larger the kick, the more difficult to bring the well back under control properly. So the well must be closed promptly. Failure doing that can cause the kick grow in size. Well Kick To illustrate how big the problem can be, just assume that, If, K=200 md, Δp=624 psi, L= 20 ft, μ= 0.3 cp, ln(Rd/ Rw)= 2.0 Therefore: Q= 0.007× 200× 624 × 20 ÷0.3 ×2.0 × 1,440 =17,472 ÷ 864 = 20 bbl/min How long does it take to close the well? What will happen after 2 minutes? Well Kick To handle, the Kick must be Characterized . Blowout A blowout is the uncontrolled flow of fluid from a wellbore. An underground blowout is the flow of fluid into a subsurface formation. Causes of Kicks A kick occurs when the hydrostatic pressure exerted by the column of drilling fluid in the hole is less than the pressure exerted by the fluids in a porous permeable formation penetrated by the wellbore. Causes of Kicks Kicks are caused by: Insufficient mud weight, Failure to keep the hole full of mud, Swab