Influence of proppant physical properties on sand accumulation in hydraulic fractures

The proppant accumulation form in fractures is related to the formation conductivity after fracture closure, also closely related to the production rate of oil/gas wells. In order to investigate the influence of proppant physical properties on sand accumulation in fractures, a particle–fluid coupling flow model is established based on the Euler two-fluid model. Geometric parameters of a fracture in tight oil wells are approximately scaled in equal proportion as the physical model, which is solved by the finite volume method. And the model accuracy is verified by comparing with the physical experimental simulation in the literature. Results show that the higher proppant concentration corresponds to the faster particle sedimentation rate, and the greater sand embankment accumulation as well. However, the fluid viscosity will increase, inhibiting proppant migration to the deep part of the fracture. Reducing proppant density and particle size will enhance the fluidization ability of particles, which is conducive to the migration to the deep fracture at the initial stage of pumping. But, it is not beneficial to have a desirable accumulation state in the middle and later pumping stage, so it is difficult to obtain a higher comprehensive equilibrium height.

Locating Source of Water Production and Performing Cost-Effective Rigless Remedial Operations in Deviated Wells Completed with Standalone Sand Screens

Wells that are already drilled and producing are the most viable sources of future earnings for all oilfield operating companies. Keeping these wells producing economically at optimal rates throughout their lifetimes is top priority. With time, some oilfield operating companies face with production related problems, such us water breakthrough. Production logging is well known technique for locating source of water breakthrough in oil and gas producers. In near-vertical, or slightly deviated wells, producing at high rates, traditional production logging tool string can deliver reliable results. On the other side, in deviated wells, producing at small rates, advanced production logging tool is required, due to presence of fluid segregation and recirculation within borehole. Our experience shows that wisely selected logging technique, depending on downhole logging environment, allows to locate source of water production with confidence for planning water shut-off remedial operations. In wells completed with standalone sand screens water shut-off operation might be complicated as often rig is required for pulling out of hole tubing with sand screens. Another method is to perform chemical water shut-off treatment that might be expensive in some cases. Alternative method is to confirm compact sand accumulation in the annulus and set through tubing bridge plug inside sand screens in wells that producing water from bottommost layers. Plug is deployed in wells without pulling out of hole tubing, as it can pass through restrictions, making this rigless intervention fifty times cheaper compared to intervention with rig. Field examples, presented in this paper, describe fit-for-purpose logging approach for locating source of water production accurately and executing unique rigless water shut-off operations in cased wells completed with standalone sand screens to increase hydrocarbons production in cost-effective way. After remedial operations we observed significant decline in water production and increase in oil rates in all wells that were intervened.

Geomorphing effect of sand fences in primary dunes of Gulf of Riga

Finding a the most appropriate solution for the problems caused by coastal eros ion is very important, as erosion prevention and habitat management measures must promote the restoration of the natural balance (order of things before anthropogenic disturbances) and restore the coastal status quo as much as possible [6; 2]. Dune fences are a very widespread erosion management tool on developed sandy coastal areas due to ease of installation, inexpensiveness, and generally positive public attitude [1]. Effectiveness and impact of fences have also been studied in many places around the world, however previous studies in Latvia have been very limited and episodic [16]. This article shows the observed dune and high beach area evolution of the coast in Riga, a somewhat developed coastal section on the top of the Gulf of Riga, Latvia, over a 4-year period from 2017 to 2020. Dune fences were installed along several short, but significantly disturbed sections of coast in 2018 and 2019. Implementation area is one of the busiest parts of the coast of Latvia dealing with the highest level of anthropogenic disturbance. Data has been derived from cross-shore transects (n=12) along the 17 km long coastal section between Daugava and Gauja river mouths. The findings generally indicate a very intense initial wind driven sand accumulation in the target areas compared to the background situation. It also seems that such a method may in the longer term be responsible for reduction of the primary dune height and beach width.

Embarking on a New Philosophy: Sand Control Design and Exclusion Method for a Field in Peninsular Malaysia, Best Practices and Lessons Learned for Future Development

Field D is a massive oil-producing field, which consists of more than 15 blocks that have been developed since 1996. All types of completion methods, from openhole stand-alone screens and cased-hole circulating packs to frac packs, have been applied to help maximize field productivity while keeping sand issues to an acceptable level. However, some wells have begun to encounter sand issues, causing a drop in productivity and in some cases become shut-in because of sand accumulation in the tubing. Small fines (<40 micron) are particularly prominent in the produced sand based on samples collected. A field development revisiting campaign was launched to target new drainage points and recover attic oil using existing slots to sidetrack to the targeted zone and install a new downhole sand control completion. The preferred treatment method is an extension pack (EP) after considering reservoir characteristics, namely close proximity to a coal layer, low permeability, and small fines production, among others. These challenges were addressed by combining the oriented perforation design and optimal sand control completion system using a single-trip multizone system, enhanced single-trip multizone system, and a stack pack with a properly designed proppant pumping strategy using xanthan carrier fluid, a fines-control acid system, and 20/40-mesh ceramic proppant with a 10-gauge wire-wrapped screen. Numerous sand control software simulations were performed to achieve tip screenout (TSO) and a sufficient pack factor while addressing all of the wellbore conditions. For the first time in this field, conductivity enhancer material was applied by dry coating it to proppant on-the-fly with the goal of controlling fines migration through the proppant pack, thus increasing porosity and leading to long-term conductivity. The process design, execution, minifrac analysis, and post-job matching for the frac pack treatment are discussed, which lead to the wells producing sand-free at higher than expected reserves and flow rates. Best practices and lessons learned from this campaign can be further used for new upcoming campaigns.

The Influence of Aeolian Sand on the Anti-Skid Characteristics of Asphalt Pavement

The influence of sand accumulation on the skid resistance of asphalt pavement was studied. Many scholars have researched the anti-skid performance of conventional asphalt pavements. However, there is a lack of research on the anti-skid performance of desert roads under the condition of sand accumulation. In this study, AC-13 and AC-16 asphalt mixtures were used. The British Pendulum Number (BPN) under different sand accumulations was measured with a pendulum friction coefficient meter, and the Ames engineering texture scanner was used to obtain different sand accumulations. The texture index of asphalt mixture was used to study the macro and micro texture of asphalt pavement under different amounts of sand accumulation, and the degree of influence of different particle sizes on BPN was obtained through gray correlation analysis. The test results show that the presence of aeolian sand has a significant impact on the macro and micro texture of the asphalt pavement and will cause the anti-skid performance to decrease. Moreover, there is an apparent positive linear correlation between the road surface texture index and BPN. The research results may provide reference and reference for the design and maintenance of desert highways.

Intussusception Associated with Sand Accumulation in a Greater Rhea (Rhea americana)

Pathoanatomical studies of diseases that affect wild animals are extremely important as appropriate measures can then be taken for the prevention and control of such diseases. We report here the case of death of a greater rhea (Rhea americana) by intestinal intussusception secondary to the ingestion of a large amount of sand. The animal was bred at the Center for Multiplication of Wild Animals of the Federal Rural University of the Semi-Arid. The animal died after presenting clinical signs of apathy, weakness, prostration, and inability to move, drink water, or eat. After death, the carcass was immediately sent for necropsy. During necropsy, intussusception was found involving the jejunum, ileum, and colon. The duodenum contained large amounts of coarse sand. The invaginated intestinal segments were reddish in color, with necrotic spots, and covered by a fibrinous exudate. Histopathological examination of the invaginated segments showed necrosis of the enterocytes, detachment of the intestinal epithelium, and the presence of inflammatory cells. The ingestion of a large amount of sand may have resulted in altered intestinal transit, contributing to the occurrence of intussusception, which resulted in ischemic alterations, intestinal necrosis, and consequent death of the animal.