American Petroleum Institute (API) 5CT high strength steels are extensively used for casing strings inwells subjected to high cyclic hydraulic fracturing loads. While non-sour grades of API steel such as P110 casing strings have been used satisfactorily for well construction, standard API P110 connections have seen higher rates of failures than pipe body failures in shale wells that require hydraulic fracturing.
Liquid loading is one of the major challenges faced by shale gas producers. This phenomenon occurs when the gas in-situ velocity is insufficient to carry the produced liquid, leading to liquid fallback in the wellbore. Liquid Loading can occur during the flowback phase, the phase where the well is producing liquid from hydraulic fracturing, as well as the production phase, and is known to cause premature gas production decline, as shown in Figure 1, as well as production instability and flow assurance issues.
In the previous parts of this series, it was established that wax deposition is an issue that arises whenever an oil composition containing appreciable wax content encounters flow, temperature, and pressure that are conducive for solids formation. The effective development of wax management strategies during Front End Engineering Design (FEED) can serve to mitigate or perhaps even prevent the high costs associated with wax remediation.
Wax deposition modeling is essential to estimate the wax deposit thickness over time in support of wax management strategy development for susceptible systems. The objective of this GATEKEEPER is to provide a high-level overview of the model commonly used in the industry to estimate the wax deposition.
Wax deposition is an issue that arises whenever an oil composition containing appreciable wax content encounters flow, temperature, and pressure that are conducive for solids formation. Wax deposition can potentially occur anywhere in the system from the reservoir to the refinery.
Mercury is commonly found in gas processing systems (midstream) and oil and gas fields throughout the world. Mercury is toxic to life and can have deleterious effects to several alloys commonly used in oil and gas production and refining industries.
Methanol (MeOH) contamination of crude oil is a growing concern in the oil and gas industry, as pipeline and refinery quality requirements become more restrictive. MeOH is used in multiple applications in the offshore oil and gas industry
A Decision Support Tool (DST) is an operational barrier used to achieve desired and predictable project outcomes as part of an overall integrated risk management strategy.
Offshore components often suffer from corrosion due to exposure to environments such as seawater, produced water, solvents, oxygen, CO2, H2S and other acids and abrasive particles. To protect equipment from degradation, coatings are applied to internal and external surfaces to provide electrical insulation, physical protection and corrosion and/or chemical resistance. Coatings can also provide thermal insulation, anti-slip, color coding, flame-retardant and anti-bio-fouling qualities to a given surface. This GATEKEEPER provides a general overview of the epoxy coatings used in offshore oil and gas service and discusses common causes of premature coating failure as well as factors affect coating quality.
Triaxial evaluation of wellbore loads is used extensively for casing and tubing string design and analysis. A triaxial based collapse strength method was recently adopted by the American Petroleum Institute (API), and an addendum issued to API Technical Report 5C3 (TR 5C3). The triaxial based collapse formula incorporates internal pressure and axial load into the calculation of casing and tubing collapse strengths. Casing and tubing that are subjected to combined loads have higher collapse strength than previous formulas would predict, permitting the use of thinner walled, or lower strength, pipe than formerly required.
In Part 1 of this GATEKEEPER series on complexity, we identified 8 key sources of project and project team complexity. In Part 2, we discuss what can be done about them.
The discussion has to start with inherent project complexity, which includes technical complexity and non-technical, or social-political complexity. A structured approach is necessary to ensure completeness. Table 1 lists a few of the sources of technical complexity, and Table 2 lists a few of the sources of social-politicalcomplexity.
Over 80% of major projects fail badly on cost, and/or schedule and/or production rate (1). The average cost overrun is 33%; on a $4 billion project that is $1.5 billion. Schedule overruns and production impairments cost atleast that much again. Consequently, we are leaving billions of dollars on the table.
Why does this happen? One reason it happens is because major projects in the oil patch are now more complex than we are capable of effectively managing.