Flow assurance problems in flowlines and pipelines include hydrate formation/blockage, paraffin wax deposition, asphaltene deposition and scale formation on the walls of pipelines, all of which impede the flow of produced hydrocarbons and associated well fluids. Conventional means for pipeline remediation to remove these restrictions include periodic and extensive pigging (either through flowline pigging loops or from subsea pig launchers), chemical injection through umbilicals and high performance thermal insulation (syntactic foam, pipe in pipe, and/or pipeline bundles).This paper presents a review of the types of pipeline restrictions and blockages, and innovative solutions for remediation, including remediation planning techniques, chemicals, debris pick-up gels and intrusive intervention. The intrusive pipeline intervention system conveys fluids directly to the area of any particular problem, using composite coiled tubing and a pipeline tractor. Two significant factors that restrict the use of an intrusive flow remediation system are the design of the production facility and the reach capability of coiled tubing. Past and current flowline designs have not considered the use of intrusive remediation systems, and to-date the use of coiled tubing as the conduit for an intrusive system has not been practical beyond a total distance of 9000 feet. Advances in composite technology have enabled the manufacture of high performance light coiled tubing, which eliminates or reduces the flowline-to-coiled tubing drag force, allowing for longer distance intervention with existing tractors. Subtle flowline design changes enable intrusive blockage remediation systems to yield significant benefits.Maintaining flow of oil and gas through production flowlines is vital to successful offshore and onshore operations. Flow assurance engineering has become a significant part of the feasibility and conceptual design stage of projects, and systems such as active heating employing either electric power or heated fluids have been considered as a method for assuring optimum flow. The application of the flow assurance solutions adds substantially to project CAPEX. In the case of chemical injection or pigging, OPEX is increased, and in most cases operational pigging causes a reduction in production during the pigging operation. In deepwater oil and gas developments the additional cost can be significant, particularly for long tiebacks. The remediation solutions presented herein obviate the need for these high CAPEX and OPEX solutions, without increased risk of long term flowline blockage.

The industry drive to develop marginal fields, heavy oil, or increased oil-recovery options from new or existing fields requires that the design of system components be examined and questioned. Extended-reach (cold water) flowlines that transport unprocessed fluids from the wellbore through to a receiving or processing facility require effective insulation systems or an active heating system to assure the integrity of the fluids in the line. Additionally, to meet flow-assurance requirements, production chemistry is used at the inlet of a flowline to prevent the formation of hydrates and to manage paraffin wax or scale formation. The production chemicals are usually injected through chemical-transportation facilities in an electrical/hydraulic-control umbilical that is laid parallel to the flowline. Flowline active-heating systems and high-performance insulation systems add significantly to the capital cost of a project; additionally, the design and fabrication of control umbilicals that include multiple chemical-injection conduits increase the capital required to develop a field. This paper presents a new concept in flowline active-heating and chemical-injection systems that will reduce the capital cost of flowline and umbilical infrastructure while enabling significant flexibility in the application of production chemistry. The system challenges of existing flowline design, umbilical design, and the philosophies of field operational maintenance/pigging are reviewed.

This paper describes a proven method to control bacteria growth in pipeline and process service fluids using irradiation technology. Service fluids are exposed to an irradiation source that disinfects the fluids and eliminates the need for biocide chemistry. The disinfection process can be used as a standalone process or in conjunction with traditional chemical treatments for many oilfield service applications.The commissioning process for pipelines typically requires hydrostatic-pressure testing. The test fluid is usually treated for potential bacteria accumulation. Using the nonchemical process of irradiation to disinfect the test fluid eliminates the need for hundreds of gallons of bactericide. The service greatly reduces employee exposure to hazard-rated biocides and associated healthand safety-related issues, significantly improving overall environmental aspects of the operation.Bacteria play an important, although usually detrimental, role in the production and transportation of hydrocarbons. The slimeforming version of bacteria can corrode surface piping and storage facilities. In addition, bacteria have been known to restrict reservoir porosity with "bio-plugging" or "bio-fouling." One anaerobic form of bacteria is sulfate reducing bacteria (SRB), which reduces the sulfate ion to sulfide. This can lead to the corrosion of flow-wetted metal components and to the formation of hydrogen sulfide (H 2 S) gas, which is extremely hazardous to humans and other animals. Fluids containing H 2 S can be damaging to production facilities not specifically designed to be H 2 S resistant.The nonchemical alternative to biocide has cost and environmental advantages over traditional chemical treatments.