This paper presents a state-of-the-art review of scale-inhibitor-analysis techniques and describes how these techniques can be used to provide cost-effective scale management. Calcium sulfate (CaSO4) in the form of gypsum and anhydrite is one of the more prevalent evaporite minerals typically found in the carbonate rocks of the western Canadian sedimentary basin (WCSB).
This paper presents an integrated approach to evaluate the key elements of asphaltene risk for deepwater projects, the strategy to manage the issues during production implementation, and aspects to be considered in the mitigation of asphaltene in the field-development plan. This paper presents a methodology that begins by determining the ADE in the laboratory. Asphaltene precipitation and deposition in production tubing and surface facilities are well-documented issues, and different methods are available to manage them.
At the 2017 SPE Oilfield Chemistry Conference, an assistant professor from Heriot-Watt University discusses the optimization of squeeze treatments delivered by diving support vessels. This paper describes a novel method of chemical dosage based on time-resolved fluorescence (TRF) that allows a simple, accurate, and efficient quantification of chemicals below parts-per-million ranges, even for double (scale/scale, scale/corrosion) quantification. Rigless coiled-tubing-unit (CTU) interventions can be effective in returning to production wells that have lost electrical-submersible-pump (ESP) efficiency because of organic, inorganic, or mixed scale deposits. The gas-producing carbonate zones of the Ghawar field in eastern Saudi Arabia have been affected by extensive iron sulfide (FeS) scale deposition, reducing overall gas production and increasing risks during well interventions. Two alkali/surfactant/polymer (ASP) floods became operational in the Taber area of Alberta, Canada, in 2006 and 2008.
This paper describes various sulfide inhibitor-testing techniques that have been applied to candidate products for the management of zinc sulfide (ZnS) and lead sulfide (PbS) in a gas/condensate field with a known relatively severe ZnS/PbS scaling problem. Mixed carbonate-/sulfide-scale problems have been reported when water is produced from carbonate reservoirs. This study presents interactions of lead sulfide and zinc sulfide coprecipitating with calcite.
When the underlying cause of flow-related issues on offshore projects is unknown, an expert said an investigation of fluid flow behavior based on an understanding of the first principles of flow assurance is necessary. This paper focuses on a numerical-modeling analysis of the acid-gas-injection (AGI) scenario in carbonate HP/HT reservoirs, and presents the way in which AGI impacts asphaltene-precipitation behavior. A presentation from the 2016 Gulf of Mexico Deepwater Technical Symposium examines a testing strategy to determine the effectiveness of paraffin inhibitors.
This feature takes a look at the work being done by companies to improve corrosion inhibitor fluids and inhibition techniques for offshore projects. A wide range of corrosive elements and compounds from a variety of crudes has led to a renewed industry focus on corrosion and the effects it has on pipelines and vessels. As the world's supply of crude becomes heavier, many of the world’s oil producers will have to think more carefully about heavy crudes and the challenges they pose for processing, storage, and transportation. Semoga and Kaji fields experienced reservoir souring and suffered a history of calcium-carbonate (CaCO3) -scale cases before a proper scale-inhibition program was implemented. Problems with a free water knockout discovered continued scale issues, leading to investigation of the reasons.
Cold finger tests are a standard method for testing paraffin inhibitors, but there is no standard testing protocol, and sometimes different labs can see inconsistent results. Shell and BHGE studied the root causes of these issues. As operators rely on longer subsea tiebacks, an upward trend in the number of plugs caused by paraffins and hydrates has been seen. New prevention and remediation methods are discussed to help solve these challenges. A test method is being developed to screen paraffin chemistries in the presence of brine, closer resembling dynamic field conditions.
An oil and gas startup has attracted the business with a major operator thanks to its ability to forecast whether production-enhancing chemicals will work as advertised. The evolution of horizontal drilling and multistage completions has changed matrix stimulation from the “more acid, better result” belief to effective lateral distribution and deeper penetration with less acid. Researchers at the University of Calgary have developed a solid pellet that can transport bitumen and heavy oil by railcar instead of pipelines. With multistage operations becoming the industry norm, operators need easily deployable diversion technologies that will protect previously stimulated perforations and enable addition of new ones. This paper reviews several aspects of the use of in-stage diversion.
Comprehension of the mechanisms that influence wax deposition in oil-production systems has not yet been achieved fully. This paper investigates the influence of the Reynolds number on wax deposition. Erosion caused by fine solid particles presents one of the greatest threats to oil and gas flow assurance, consequently affecting material selection and wall-thickness design. Offshore production assurance continues to drive new production technology applications and approaches. The three papers highlighted here focus on developing analytical tools and performing root-cause analyses while providing safe, cost-effective, and reliable operations.
Halliburton broke ground in Saudi Arabia for the first oilfield chemical manufacturing reaction plant in the Kingdom. Researchers from Chevron are looking into a new approach to understand the drivers of polymer hydration. How might this affect the design of mixing systems in the field, and could it affect offshore EOR applications? A new purpose-built center offers cutting-edge research, formulation analysis, and testing in one location. This paper considers some of the challenges and learnings associated with the application of chemicals for preservation of coated pipe/flowline for a major liquefied-natural-gas (LNG) project in Australia.