Hamoud Al-Hadrami

A Comparative Study of Lost Circulation Materials

In this article, the objective is to identify an alternative lost circulation material (LCM) to combat typical operational problems associated with drilling mud losses. These problems cost the local oil company significant downtime. In the oil industry, and, of course, to the local oil company, most of the commercial lost circulation materials have been tested with different levels of success. The trend now is to rethink different ways to better tackle the mud losses intricate problem and reduce drilling costs. The objective is to investigate possible gelling and bridging agents that are currently used by other industries. To start, an extensive literature search for possible LCM candidates from industries like construction, refrigeration, pleasure-boat manufacturing and others is embarked on. The next challenge would be to envisage a thorough chemical screening and testing program to come up with an LCM that could be effective if pumped through thief zones. The effectiveness yardstick could then be measured by: (1) solving the problems of placement, (2) temperature, (3) pressure, etc.

Injection of biosurfactant and chemical surfactant following hot water injection to enhance heavy oil recovery

This study investigates the potential of enhancing oil recovery from a Middle East heavy oil field via hot water injection followed by injection of a chemical surfactant and/or a biosurfactant produced by a Bacillus subtilis strain which was isolated from oil-contaminated soil. The results reveal that the biosurfactant and the chemical surfactant reduced the residual oil saturation after a hot water flood. Moreover, it was found that the performance of the biosurfactant increased by mixing it with the chemical surfactant. It is expected that the structure of the biosurfactant used in this study was changed when mixed with the chemical surfactant as a probable synergetic effect of biosurfactant-chemical surfactants was observed on enhancing oil recovery, when used as a mixture, rather than alone. This work proved that it is more feasible to inject the biosurfactant as a blend with the chemical surfactant, at the tertiary recovery stage. This might be attributed to the fact that in the secondary mode, improvement of the macroscopic sweep efficiency is important, whereas in the tertiary recovery mode, the microscopic sweep efficiency matters mainly and it is improved by the biosurfactant-chemical surfactant mixture. Also as evidenced by this study, the biosurfactant worked better than the chemical surfactant in reducing the residual heavy oil saturation after a hot water flood.

Evaluation of Polyurethanes as Potential Mud Loss Control Agents

In this article, polyurethanes have been selected as potential lost circulation materials (LCMs) that will be introduced in wellbores having experienced serious drilling mud losses. The chemicals will be mixed at surface, pumped downhole, let to bridge/foam and seal open fractures/channels. Different tests have been carried out to investigate better ways of mixing and handling polyurethanes before pumping. In that, prospects of slowing down polyurethane reactions by decreasing the amount of activator and adding different proportions of diesel were investigated. Testing the effect of moisture on polyurethanes also was tested. Furthermore, testing using diesel, toluene, xylene, Musol, acetone, glycol, light crude oil, Safrasol as carrier fluids was undertaken. The mixing sequence of diluents and polyurethanes also was thought of and the effect of mixing water on foaming reaction also was investigated. Placement under pressure of pumped polyurethanes also was investigated. It was revealed that pressure enhances polyurethane sealing capability. Adhesion and sealability experiments, in open fractures with apertures of 0.5 mm and 1.5 mm, also indicated that tested polyurethanes are the best candidates guaranteeing a good spreadability within open fractures. Bridging and sealing fracture apertures of up to 5 mm have been achieved with success. Sealability of even larger fracture apertures amounting to 2 inches also has been accomplished.