Applying Radial Acoustic Amplitude Signals To Predict Intervals of Sand-Stuck Tubing

Abstract

Abstract The reuse of existing well bores is one cost saving technique employed by oil and gas producers in mature fields. This process usually requires the removal of tubing and packers to allow the well to be deepened or side-tracked. The tubing removal process is often made difficult due to its being stuck inside casing due to mechanical binding, or binding caused by dehydrated mud or sand in the annulus between the tubing and casing. Conventional direct and indirect methods of finding the stuck point(s) along an interval of tubing, such as Free Point Indicator Tools or Acoustic Attenuation measurements, have proven themselves useful in finding the point(s) where the tubing is stuck. However, when the sticking is due to uncompacted sand that has entered the annular space between the tubing and casing, these conventional stuck pipe indication methods are often inconclusive. Technological advancements in the design and development of slim, 1-11/16 in. OD, radial cement bond tools allow the application of a new measurement to find sand-stuck tubing intervals. These tools provide up to six independent, short-spaced, acoustic attenuation measurements distributed radially around the tool body. When recorded inside tubing, their increased sensitivity to sound attenuation, as compared to conventional omni-directional amplitude signals, allows sand intervals along the outside of the tubing to be distinguished from intervals where little or no sand is present. This information is used to select the best depth to sever or back-off the free tubing in order to reduce the interval length and expense associated with the washover process required to remove the remaining tubing from the wellbore. An overview of conventional stuck pipe recovery techniques is discussed along with a brief explanation of applied acoustic technology. A case example of a South Louisiana well is presented to demonstrate the application and illustrate the cost savings gained by use of this newest technology.