Development and application of easy-to-retrieve even steam injection string in horizontal wells

The even steam injection string for horizontal well can realize even steaming in long horizontal section of horizontal well for thermal production heavy oil and improve steam injection quality. However, compared with the often used ?73 mm tubing, the conventional even steam injection string is larger in outside diameter, so there are a number ofvariable diameter on the whole string and hence the string is hard to retrieve; in addition, the steam distribution valve is directly opposite the screen tube, so there exists the risk of screen washout while stream injection. For this reason, an easy-to-retrieve, anti-sand burial even steam injection string for horizontal well is developed, which is composed of ball-like safety release joint, small diameter lateral steam distribution valve and small diameter check valve, etc. The steam comes out of distribution valve on side orifices, so avoiding the risk of screen washout; the outside diameter of the whole string is small without obvious diameter varieties, which reduces the risk of being unable to retrieve the string due to sand burial. The string is equipped with safe connections, so when the string is buried, the release can be realized to retrieve the upper tubing and then the lower tubing shall be fished. This technology enjoys a favorable prospect and promotional value in heavy oil horizontal wells with severe sand production and screen completion.