Enable fracturing or refracturing operations to proceed as planned in unconventional gas and oil plays (shale gas and tight oil) with the required well integrity.
Unconventional reservoirs require special drilling and completion practices to achieve economic recovery of hydrocarbons. Because these unconventional reservoirs have very low permeability and porosity (and in the case of shale gas wells, contain hydrocarbons that are adsorbed to the rock surface as well as stored in the primary and secondary porosity), extensive hydraulic fracturing is required to provide the hydrocarbon pathways required for economic production. This is achieved by drilling long horizontal wells through the reservoir and fracturing this lateral in many stages from the toe to the heel of the lateral. Consequently, the completion cost for some of these wells may exceed the drilling cost.
Also, the combination of high dogleg severity, high wellbore pressures during fracturing, complex perforating, and complex mechanical requirements for frac diversion can cause casing damage which can stop completions, and in some cases require the drilling of a new well.
Even when everything is done as planned in these wells, sometimes production is not what was expected and refracturing the well may be necessary to achieve the desired hydrocarbon recovery.
Casing damaged from drilling and completion operations in unconventional shales can be repaired by Enventure’s ESeal Patch or ESeal Liners in the form of multiple- and single-joint solutions. These can be used to repair damaged connections, split casing, and damaged frac sleeves as well as to cover unwanted perforations, to enable fracturing and production operations to proceed.
In addition, ESEal Liners can be used as a primary barrier to isolate perforations, providing injectivity assurance for refracturing operations. Multiple-joint ESeal Liner solutions are available for 5-1/2-in. and 7-in. production casing for fracturing and refracturing operations in wells having bottom-hole temperatures < 210°F. Single-joint solutions and partially expandable solutions are available for 4-1/2-in. and 5-1/2-in. base casing up to 350°F for HPHT fracturing and refracturing operations.
Single-joint and multiple-joint expandable patches and liners have been used to restore many shale gas and tight oil wells for fracture operations and production. In wells in the Bakken, expandable single joints have covered defective frac sleeves allowing the lateral section to be fractured as planned, saving millions of dollars of sidetrack, drilling, and completion costs for a new lateral.
In wells in the Piceance, single joints have repaired casing splits in the middle of the productive interval by enabling hydraulic fracturing to complete the bottom half of the interval, recovering over 50% of the wells reserves..
In wells in the Marcellus, multiple-joint expandable liners have repaired large sections of the lateral , enabling the well to be completed and avoiding millions of dollars to construct a new lateral section. Even longer sections of multiple-joint liners have been used in the Marcellus and Barnett Shales to assure optimal refracturing, optimizing recovery of otherwise lost reserves.
