New reserves often mean hostile conditions
Finding and producing new hydrocarbon reserves involves contending with increasingly harsh downhole conditions. Attractive new prospects like deepwater high-pressure wells in the Gulf of Mexico, the increasing use of thermal recovery techniques, and the commercial viability of previously uneconomic plays has dramatically increased the requirement for HPHT technology.
Rigorous qualification means well-defined ratings
Multiple temperature and pressure cycles together with shocks and vibration at different frequencies realistically simulate field conditions. Designing and operating equipment that can withstand these hostile environments is difficult but the real challenge is to deliver high-quality measurements reliably. Schlumberger has long been a leader in bringing metrology to the oil field delivering purpose-built, exhaustively tested, field-proven services and products for every stage of an HPHT well.
A complete range of products including drill bits, rotary steerable systems (RSS), turbodrills, MLWD equipment, drilling fluids, and cement, with associated services.
Wireline logging and well testing services to accurately characterize your reservoir rocks and fluids.
Completions services and products for optimizing productivity.
Proper preparation for hostile conditions is a combination of proven risk assessment and mitigation process coupled with a real-time feedback loop during the actual job execution.
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Life Cycle Profiles
We develop lifecycle profiles that begin with customer collaboration so that we are able to better understand all aspects of the task at hand. Operational profiles are critical in achieving high reliability, and in these we describe in detail the operating envelope, expected quality of the results, and duration of the job.
Duration of exposure, a critical HPHT parameter
The length of time that a product must withstand the hostile environment is a crucial factor. For example, logging and testing tools and drilling muds are exposed for a limited time but cement and completions products must survive for many years. It is also essential to repeatedly cycle the product through its full range of temperature and pressure to ensure consistent performance over its operating life.
Mission-specific HPHT tests
Laboratory evaluations fall into three principal categories:
- Fluids: Testing under simulated downhole conditions must determine if the fluid can be prepared and properly placed in the well and whether it will be sufficiently stable to perform its intended functions. The testing protocol is often complex, involving rheology, filtration, corrosion, and mechanical-property evaluations.
- Mechanical devices: This category includes seals, screens, and packers, along with rotating and reciprocating parts such as shafts, pistons, valves, and pumps. In addition to HPHT exposure, qualification testing includes mechanical shocks and contact with hazards such as hydrogen sulfide (H2S); carbon dioxide (CO2); and erosive, particle-laden fluids. Seals that can survive up to 260 degC [500 degF] under static conditions are only rated to 150 degC [300 degF] for dynamic applications in a mud environment with some sand inclusions.
- Electronic components and sensors: Engineers must determine the operational time limit under simulated downhole conditions. The key challenge involves the stability of plastic or composite materials that provide modern electronics with structural integrity and insulation.
Extreme qualification process for maximum reliability
The qualification process must simulate the harshest conditions that may be encountered and is customized for the product. Numerous tests are conducted at a system level, as well as for individual components, electronics boards, and subassemblies, often extending over several weeks or months. They can include
- thermal aging
- thermal cycling
- pressure cycling
- thousands of shocks along each axis at normal and elevated temperatures
- vibration at multiple frequencies and temperatures
- cold storage
- low- and high-temperature operations.
The process concludes with extended reliability testing, during which the equipment is subjected to a lengthy operational test under cycles of temperature, power, functional load, and shock. An extensive database compiled from these tests is used to define preventative maintenance procedures, maximizing reliability at each deployment.