Drillable Sliding-sleeve Open-hole Staged Fracturing Technology

Scope of Application
This technology is applicable for 6" and 8-1/2" open holes. 
Technical Principle
This technology can isolate horizontal well into several sections with packer and sliding sleeve according to the need of reservoir development. During fracturing, sliding sleeve is opened through drop-ball ejection and specific construction can be carried out accordingly. Layered oil production and water injection can also be carried out. Open hole packer isolates every layer. A ball seat is installed in every sleeve and the size of ball seat increases from the bottom to the top with a differential of 0.11" or 0.125". Different low density balls are sent into tubing and pumped into corresponding ball seat. The next production zone can be treated by opening the sliding sleeve. The toe-end sliding sleeve is opened in the same way of a differential pressure sliding sleeve. Drillable and millable materials are used for ball seat manufacturing. Grinding and milling is carried out after fracturing, so as to establish a full bore shaft. 

Construction Tools
  • Linear Hanger—No other auxiliary tool is required when setting and the complete setting pressure is 3500psi.
  • Open hole packer—The packer, which can resist a differential pressure over 70MPa and a temperature around 150 , consists of a hydraulic compression type single rubber sleeve and two water swellable rubber sleeves and is equipped with a self-locking system.
  • ZSS drillable fracturing sliding sleeve—After fracturing, the ball seat inside the sliding sleeve can be drilled, so as to establish a full bore shaft. Maximum 26 stages can be achieved.
  • Differential pressure sliding sleeve (toe-end sliding sleeve)—The open of opening the differential pressure sliding sleeve can be adjusted. The shear stress when opening the sliding sleeve is 19.7MPa and the temperature resistance of the sliding sleeve is 149C.
  •  Fracturing Dissolvable temporary ball sealer—The strength of the composite material manufactured fracturing temporary ball sealer is increased, so that the problem of fracturing failure due to the broken of temporary ball sealer during construction is solved.

Technical Features

 A well can be isolated into many sections so that the requirement of overlength horizontal well staged fracturing can be satisfi ed.

 The ball seat inside sliding sleeve can be drilled and milled, so as to establish a full bore shaft.

 The design of non-stop pumping and drop-ball ejection ensures the smooth pumping of the drop-ball into the ball seat of sliding sleeve.


Service Ability and Performance

As of June 2013, the Drillable Open-hole Staged Fracturing Technology has been successfully applied for 243 wells in domestic onshore oil fi elds with a success rate of 100%. Maximum

17 fracturing stages can be achieved on a single well. For instance, the DP-xx well obtained a pumping termination pressure of 14.2MPa and a natural gas open flow capacity of 27.5×104m3/d after being fractured into 9 stages with 2976.2m3 of fracturing liquid and 396.8 m3 of sand.