Real-Time and In-Situ Detection of Calcium Carbonate Scale in a West Texas Oil Field

Abstract

A novel technique has been developed to detect the onset and increase of calcium carbonate scale deposition from oilfield production fluids. This method uses an attenuated total reflectance (ATR) probe, called the scale sensor, to detect scale formation in situ. Because this method is based on existing technology and requires little supporting equipment, a simple, cost-effective monitoring device could be placed in many locations within a production system. This method could provide a system-wide, in-situ, real-time response to calcium carbonate scale formation at its earliest stages.As a first step toward evaluating the effectiveness of this new technology, the scale sensor was field tested at a west Texas oil field. The scale sensor was observed to detect the deposition of calcium carbonate under static and flowing conditions in actual produced fluids. In the static tests, crude oil, suspended solids, and other endogenous materials did not affect the scale sensor's response. Under flowing conditions, like those found in the production flowlines at this west Texas oil field, scale sensor response was observed to correlate to the chemical injection rate of both the scale inhibitor and the dispersant. On the basis of the results from the scale sensor, the scale inhibitor's injection point will soon be moved to the wellhead.

Fundamental Study on the Development of Fiber Optic Sensor for Real-time Sensing of CaCO3 Scale Formation in Geothermal Water

“…[19][20][21][22][23][24][25][26][27][28][29][30][31][32] Smith et al investigated the effects of an inhibitor and a dispersant on the CaCO3 scale formation of the oil field using the standard ATR element. 33 Several groups have reported on the fiber optic method for monitoring CaCO3 precipitation by using an exposed core fiber optic, monochromatic laser light and detector. [34][35][36][37] The detection principle was based on the percentage of total internal reflection within the fiber optic core, which was affected by the high refractive index of CaCO3 scale formation on the core surface.…”

Detecting and Monitoring Industrial Scale Formation Using an Intrinsic Exposed-Core Optical Fiber Sensor

“…Furthermore, scale formation results in a permanent flux decline, which reduces the efficiency of industrial processes . It is estimated that scale formation costs industry millions of dollars per annum. , Calcium carbonate (CaCO 3 ) and calcium sulfate (CaSO 4 ) are among the most common scale-forming minerals found in industry owing to the presence of calcium, sulfate (SO 4 2− ), and bicarbonate (HCO 3 − ) ions in many process waters . Among other significant scale-forming minerals, calcium oxalate (CaC 2 O 4 ) is responsible for much of the intractable scale deposited in sugar mill evaporators. , Many factors affect the formation of scale, including the supersaturation concentration, which is defined as the concentration exceeding the saturation concentration, temperature, reactant flow velocity, and solution pH .…”

“…4 It is estimated that scale formation costs industry millions of dollars per annum. 5,6 Calcium carbonate (CaCO 3 ) and calcium sulfate (CaSO 4 ) are among the most common scale-forming minerals found in industry owing to the presence of calcium, sulfate (SO 4 2-), and bicarbonate (HCO 3 -) ions in many process waters. 4 Among other significant scale-forming minerals, calcium oxalate (CaC 2 O 4 ) is responsible for much of the intractable scale deposited in sugar mill evaporators.…”

The Evolutionary Characteristics of Lower Permian Keziliqiman Reefs in the Southwest Margin of Tarim Basin, Northwest China

“…Since the late 1970s, with the exploration and development of reef oil and gas reservoirs in south China, research on Permian reefs in that area has made great progress, and there are many relevant research achievements. At the beginning of the 21st century, with the exploration and development of Ordovician carbonate reservoirs in the Tarim Basin, major breakthroughs were made in research on Ordovician reefs in the basin [7][8][9][10][11][12][13][14]. However, the research progress of the Permian reefs in the Tarim Basin is quite slow.…”