Most reservoirs in the US under operation by small producers have become mature due to extended waterflooding. In fact, an estimated 80% of the total number of oil wells in the US are now classified as "marginal." The mature reservoirs accessed by these wells usually have a high water cut, in the range of 80% to 90%. Also, the industry typically leaves about 65% of oil behind after many years of waterflooding because of reservoir heterogeneity and incomplete sweep of the formation. Excessive water production becomes a major problem as these oil fields mature.
Hydraulic fracturing solutions use a gelling agent known as guar gum. Guar beans are grown in a number of countries, including the United States. The endosperm of the guar bean is ground to produce an off-white powder known as guar gum (guar). Guar acts as a gelling agent, which can be crosslinked by adding additives, such as barium, to tailor the molecular weight of the guar solution. Crosslinking the guar increases the viscosity of the solution, which results in a gelatinous material having sufficient surface tension to transport a proppant (e.g., sand), which is used to maintain cracks and fissures in an open condition in the geological layers to allow oil and gas to flow to the collection well.
Wax or paraffin formation in subsea pipelines is a major problem in the upstream petroleum industry, accounting for tremendous economic losses. Researchers have reported that approximately 85% of the world’s oils encounter problems from wax formation (Thota and Onyeanuna 2016). In this manuscript, the authors briefly discuss the mechanism of wax formation in pipelines. Next, a review of various wax-mitigation technologies is provided. The review includes citations of various thermal, chemical, mechanical, biological, and other innovative methods reported by previous researchers and used in the industry.