页岩气田改造有难题？看TBlockSure 如何引导

Operators have traditionally resorted to drilling more wells to offset the drop in production. As the current economic climate forces the industry to identify more time- and cost-effective methods for prolonging the productive life of shale wells, refracturing is quickly becoming the preferred alternative, especially for wells with completion inefficiencies that hinder production or leave significant untapped hydrocarbon reserves. As horizontal multistage fracturing becomes common- place, there is an increased need for longer lasting, more reliable diverting technologies such as advanced degradable diverters. The Weatherford TBlockSure diverting agent and stimulation enhancer is a solid material—made of a proprietary degradable mesh—that provides superior isolation and diversion compared to traditional diverters.

Feature

The TBlockSure® temporary diverting and fluid-loss-control agent for stimulation or workover applications is made of a degradable mesh (US 7 and US 100). This agent has a short-lived blocking effect that provides superior zonal isolation and mechanical diversion in comparison to traditional diverters.

Degradable diverters can be deployed easily and with minimal equipment requirements, which is beneficial from a cost-reduction standpoint. The only equipment required at the well site is the agent and a dedicated pumping unit that can be easily installed at the wellhead.

Although the agent is compatible with standard pumping equipment, using the specialized separate pumping unit prevents the agent from contaminating other equipment in the fracturing feet by remaining in the valves and seats in the fluid ends of fracturing pumps.

The agent is then simply pumped downhole using either slick water or, more commonly, a viscous fracturing fluid. It can be deployed in any well regardless of borehole size, geometry or the original fracturing method used. Addition- ally, the TBlockSure agent is available in a high-tempera- ture version for environments between 82℃ and 149℃ (180℉ and 300℉) and a low-temperature version for environments between 54℃ and 82℃ (130℉ and 180℉).

Once in place, the agent creates an enhanced zonal barrier or perforation sealant that withstands high treatment pressures. Only at a predetermined time—depending on the bottomhole temperature, the duration of exposure to
the temperature and the pH—the mesh dissolves into liquid form to reopen fractures or perforations and to enable flow. No secondary treatment is required to start the degradation process.

However, chemicals such as breakers or pH-adjusting agents can be added to the TBlockSure agent to control how quickly or slowly the material degrades. Although the degradation process requires shut-in time, this time can be used to prepare production facilities and should not cause a significant delay to operations.

Benefits

• The TBlockSure® agent provides effective zonal isolation and fluid diversion.
• The agent provides a highly effective, temporary plug for stimulation or workover fluids.
• The agent generates fracture-network complexity in naturally fractured reservoirs.
• The agent reduces or eliminates bridge plugs and plug mill-out time, along with the associated costs.
• At a predetermined time, the agent degrades into a water-soluble byproduct that is compatible with most stimulation and produced fluids.

High and Low Temperature (LT) Temporary Diverting Agents

Two sizes combine for enhanced permeability reduction US 100 mesh and 7 mesh

TBlockSure100

• Temporarily blocks perforations with temperatures between 180℉ and 300℉ (82℃to 149℃)
• Combines with TBlockSure7 for maximum reduction of permeability

TBlockSure7

• Temporarily blocks perforations with temperatures between 180℉ and 300℉ (82℃ to 149℃)
• Combines with TBlockSure100 for maximum reduction of permeability

TBlockSure100LT

• Temporarily blocks perforations with temperatures between 130℉ and 180℉ (54℃ to 82 ̊C)
• Combines with TBlockSure 7LT for maximum reduction of permeability

TBlockSure7LT

• Temporarily blocks perforations with temperatures between 130℉ and 180℉ (54℃ to 82℃)
• Combines with TBlockSure100LT for maximum reduction of permeability

Applications

• Completing vertical, horizontal, and openhole wells
• Sealing existing perforations and breaking down new perforations in refracturing well candidates
• Providing zonal isolation without the use of bridge plugs
• Diverting fluids during treatments for increased zonal coverage
• Treating existing perforations and zones with collapsed or restricted casing
• Sealing ports on damaged or inoperable sliding-sleeve systems
• Temporarily sealing damaged casing and misfired or out-of-zone perforations
• Restoring lost circulation during drilling or well cleanouts

Application case

The TBlockSure agent successfully operated as a mechanical diverter on three horizontal wells in the Marcellus shale play.

Two new wells needed temporary zonal isolation on a per-stage basis. The third well required the sealing of existing perforation clusters from a previous treatment and achieving breakdown pressure into new perforations. The operator required a diverter as a zonal isolation system to seal off a previously treated stage and to complete the well, one stage at a time. With well depths between 8,500 ft (2,591 m) and 9,000 ft (2,743 m) and temperatures between 150℉ (66℃) and 155℉(68℃), the TBlockSure agent enabled optimal diversion pressures while 28 total stages—with 54 perforations each— were completed.