Assessing surface engineering solutions for oilfield scale; correlating laboratory tests to field trials

Mineral scale deposition on surfaces of oil production equipment has been recognised as a major flow assurance problem. Most of the mineral scale deposition work published has solely focused on laboratory experiments and very little data are available that demonstrate such results are relevant and can be scaled-up to field environments. The current study focuses on mineral scale formation on surfaces and compares laboratory results with field data. A field test has been running for half a year on commercially-coated pipe spools along with uncoated ones. The different pipe sections were positioned along a water line injection system in an oilfield. In the laboratory, a standard bulk jar test was used and the ability of a range of chemically and morphologically modified coatings to prevent/reduce mineral scale surface fouling were assessed under different flow conditions (ranging from laminar to turbulent flow). The current study shows that if properly selected, surface engineering offers great promise as an approach to prevent mineral scale deposition in the piping system of oilfields

The multi-depot heterogeneous VRP with backhauls: formulation and a hybrid VNS with GRAMPS meta-heuristic approach

In this paper, we investigate the Multi-Depot Heterogeneous VRP with Backhauls. Though the problem is a generalisation of three existing routing problems, this is the first time this combined routing problem is investigated. A mathematical formulation is first presented followed by some tightening. A powerful and novel hybridisation of Variable Neighbourhood Search (VNS) with the Greedy Randomized Adaptive Memory Programming Search is proposed. As there are no problem instances available for bench-marking and evaluation purposes, we generated data sets by combining those from existing vehicle routing problems. The proposed meta-heuristic obtains a number of optimal solutions for small instances and yields about 13% gap from the lower bounds compared to nearly 40% and 20% average gap values for our CPLEX implementation and the VNS without hybridisation, respectively