簡介：威德福公司安全閥綜合系統能夠實現單源式油井重開，在認為無價值的油井中，通過恢復其中一部分有價值的生產層，達到恢復油井產量的經濟目的。

From spending US $500,000 on land to as much as $7 million offshore, operators are finding it harder to justify the astronomical costs of a workover for troubled wells in today’s cost-sensitive environment. Nonetheless, opting to abandon still-valuable reservoir assets is not necessarily the answer.

Weatherford now offers an alternative．　 an integrated safety-valve system that revives failed wells at a fraction of the cost of a workover. Using the Renaissance safety-valve system, operators can reevaluate where to increase production and extract revenue from assets once deemed unsalvageable.

Single-source safety valve solutions 

Development of this solution combines field insights and technical acumen. Components include wellhead, completion, production chemistry, capillary injection, safety valve, wireline, and slickline experts came together to develop the Renaissance system to solve three common late welllife problems.

To protect people, property, and environment, a high percentage of wells use safety valves as a security measure to shut in production if well integrity is compromised. Areas such as the North Sea have relied on safety valves for years. And the rash of hurricanes and associated facility damage in the US Gulf Coast during the past several years has proven the effectiveness of safety valves.

Though essential, and often mandated in various regions, safety valves can present a number of challenges in producing wells. Liquid loading and damaged safety-valve components such as sealbores or control lines are some of these challenges. Considering the high workover costs required to remedy these scenarios, operators sometimes opt to walk away from potentially high-value assets that have become an economic challenge.

In the past if an operator was offshore in the Gulf of Mexico and the safety valve failed, another one could not be run, and the well was effectively shut in and could not be produced. Workovers are one solution. However, the Renaissance safetyvalve system is helping operators stay the course and revive wells they normally would abandon without incurring exorbitant workover costs.

Evolved from the company’s Optimax series of safety valves, the Renaissance system comprises the following technologies:
• Renaissance WDB (Weatherford damaged bore) safety valve, which is set into existing safety-valve landing nipples and tubing-retrievable safety valves that have sealbores damaged beyond normal valve functioning.
• Renaissance WDCL (Weatherford damaged control line) safety valve, which remediates when the safetyvalve control line fails, becomes blocked or leaks.
• Renaissance Opti-Chem WCS (Weatherford capillary system), which provides the security of a surface-controlled, subsurface safety valve while providing for continuous chemical injection downhole.

Although nonexistent approximately 18 months ago, today all three technologies help remedy the three greatest challenges of safety-valve-installed wells?loss of hydraulic control of the safety valve (caused by damaged sealbores), blocked or failed control lines, and maintenance of a fail-safe subsurface barrier when capillary injection is installed.

For the WDB system, which has a 95% success record in more than 200 wells, the only work-around to restore safety-valve integrity would be to pull the tubing and replace it or use retrievable packers to straddle the damaged sealbores and a ported sub to provide control to a reduced inside diameter (ID) inset valve. All are expensive alternatives. Weatherford installed WDCL successfully for a major operator in Holland; 27 future offshore wells with damaged, blocked, or leaking control lines have been identified?which will help the operator avert the significant costs of workovers. The operator faces regulations that will require it to install surface-controlled safety valves in existing onshore assets. This new requirement would potentially cost $50 million to workover before producing the wells. TheWDCL system will significantly reduce these costs.

Industry-changing benefits 

While all three Renaissance systems offer benefits to operators, Opti-ChemWCS’ new chemical-injection design runs the capillary-injection string with integral internal bypass that maintains all the safety functions of the safety valve. The technology enables operators that need production- enhancing chemicals, such as foamer, paraffin, scale or corrosion inhibitors, or freshwater for salt mitigation, to inject these solutions into the well to enhance production without undermining well integrity and without executing a workover.

Any well in the world is a potential candidate for some type of production enhancement chemical?and not just foamers; this is a chemical delivery system. Projects today are running capillary-injection systems that are injecting H2S (hydrogen sulfide) scavenger to reduce the severity and corrosion effect of hydrogen sulfate gas on 7,000-to-10,000-b/d oil wells in Kuwait.

In addition, because the company designed the cap string to run through the center of the completion, WCS does not significantly reduce the tubing ID and flow area like competing alternatives.

If an operator has a 31⁄2-in. tubing that needs an insert safety valve, the recommendation also would be a 31⁄2-in. safety valve where we have modified the internals to retain ID.

Providing greater efficiencies 

While relatively new in the safety-valve industry (the technology has been available for the past seven years), these technologies have caught on largely because success rates during this time have been very high.

Major clients are eager to apply the Renaissance technology because they recognize the production potential and are ready for a single-source solution.

The company anticipates it will run more than 100 applications in the next 18 months. With the Renaissance safetyvalve system, operators can rely on one source without having to bring in multiple capillary strings or wellhead companies. In the end, this translates into more efficient production, without the use of expensive workovers.