Research and Field Application of Controllable Blowout Prevention Technology After Shale Oil Fracturing

Daqing Gulong shale oil has newly increased proven geological reserves of 1.268 billion tons, which is an important replacement resource for the construction of a century-old oilfield. The timely pumping of shale oil well after fracturing can effectively maintain the reservoir energy and extend the well life. Due to the high wellbore pressure after fracturing, there is a bottleneck problem that can not be pumped into production in time. The existing blowout prevention technology has blowout prevention defects, which can not meet the high-pressure blowout prevention needs of shale oil. Therefore, based on the technical idea of “reliable high-pressure sealing and effective repeated opening and closing”, the metal and non-metallic double sealing blowout prevention mechanism was innovatively designed to ensure the effective repeated opening and closing. The chip mounted carbide slip mechanism was invented to achieve reliable anchoring of high hardness casing. The blowout prevention tool can bear the pressure of 35 MPa and the temperature of 120 ℃. Six wells were tested in Gulong shale oil field. The success rate of blowout prevention was 100%, and the success rate of fishing was 100%. The blowout prevention of the whole wellbore was effectively realized, providing technical support for green, efficient and low-cost operations of early pumping and production and subsequent pump inspection after fracturing.