This research investigates the use of charge coupled device (abbreviated as CCD) linear image sensors in an optical tomographic instrumentation system used for sizing particles. The measurement system, consisting of four CCD linear image sensors are configured around an octagonal shaped flow pipe for a four projections system is explained. The four linear image sensors provide 2,048 pixel imaging with a pixel size of 14 micron × 14 micron, hence constituting a high-resolution system. Image reconstruction for a four-projection optical tomography system is also discussed, where a simple optical model is used to relate attenuation due to variations in optical density, [R], within the measurement section. Expressed in matrix form this represents the forward problem in tomography [S] [R] = [M]. In practice, measurements [M] are used to estimate the optical density distribution by solving the inverse problem [R] = [S]−1[M]. Direct inversion of the sensitivity matrix, [S], is not possible and two approximations are considered and compared—the transpose and the pseudo inverse sensitivity matrices.
This paper summarizes the overall response from the CO2-foam injection in the Salt Creek field, Natrona County, Wyoming. Conformance control of CO2 by creating foam between supercritical CO2 and brine to improve the sweep efficiency is documented in this paper. The foam was implemented in an inverted fivespot pattern in the Salt Creek field where the second Wall Creek (WC2) sandstone formation is the primary producing interval, with a net thickness of about 80 ft and at a depth of approximately 2,200 ft. The initial phase of the foam pilot design involving identifying the pilot area, performing coreflood experiments, performaing dynamic reservoir simulation for history match, and forecasting with foam have been documented in the literature. As a part of the foam pilot monitoring, a gas tracer study was performed before and after the injection of foam in the reservoir. The initial planning, monitoring, and part of foam response is covered in earlier publications. The last surfactant injection in the field was in June 2016. This paper provides the complete analysis of the results from the foam pilot. The foam pilot was successful in demonstrating the deeper conformance control and improvement in sweep efficiency, which resulted in 25,000 bbl of incremental oil. Also overall, a 22% decrease in CO2 injection amount is realized due to better utilization of CO2 compared to the baseline.
This paper describes the study of the effect of asphaltene precipitation and deposition on the development of the Marrat field using a compositional simulation model with asphaltene modeling facilities. The model enables the simulation of asphaltene precipitation, flocculation, and deposition including adsorption, plugging, and entrainment, and the resulting reduction in porosity and permeability and changes in oil viscosity and rock wettability. A workflow was established in the study to i) characterize the equation of state (EOS) by analyzing the fluid PVT and asphaltene data from the lab; ii) calibrate the asphaltene model input parameters using the core flood experimental data; and iii) incorporate the EOS and the asphaltene parameters into the full field simulation model. The model was used to analyze the effects of asphaltene on various development scenarios, including depletion and water injection. For each scenario, the following were calculated and analyzed: field performance including production of oil, gas, and water; asphaltene behavior including precipitation, flocculation, adsorption, plugging and entrainment; formation damage and the effect of rock wettablity changes. The results show that the formation could be severely damaged near the producers where asphaltene is more likely to precipitate because of lower pressures (below the asphaltene onset pressure) and longer time exposure to a larger amount of oil. Formation damage could be reduced by flushing away the deposited asphaltene using higher flow rates if plugging is not significant. The water injection scenario with higher injection rate and higher production rate with BHP limit above 6,000 psia results in less asphaltene adsorption, more entrainment, and therefore less deposition. This in turn causes less permeability damage and more oil production. Introduction The Kuwait Oil Company (KOC) encountered the problem of asphaltene precipitation in Jurassic production wells located in producing areas in West and South East Kuwait. In West Kuwait (WK), the Jurassic production is primarily from the Marrat field. Out of about 45 wells in WK-Marrat 50% have a history of asphaltene cleanouts. These wells contribute to around 7% of the total oil production from WK which can amount to as much as 50 Mbbl/d. Here the reservoir pressure (around 9,500 psi) is considerably above the asphaltene onset pressure (AOP) (estimated between 2,000 psi to 4,000 psi). Therefore, there is no likelihood of asphaltene deposition in the reservoir. However, during production as the pressure of the produced fluid inside the tubing goes below the AOP, asphaltenes start to precipitate from the crude. Asphaltenes gradually deposit in the tubing, reducing its diameter, and in the process cause production rates to drop; eventually the well completely ceases to flow. Once this has occurred, the tubing in the well must be cleaned out to restore the well to production. The Marrat reservoir lies in the South Eastern part of Kuwait, within the giant Burgan field complex. It is a carbonate reservoir, existing at an average depth of 11,000 to 11,500 ft, subsea. The reservoir fluid is generally light, ranging in quality between 36 and 40 API degrees. The original oil in place is estimated to be two billion stock tank barrels. The original reservoir pressure at discovery was determined to be 9,650 psia. A log with the average properties of the reservoir is shown in Figure 1. The fluid is known to be asphaltenic 1 in nature, as evidenced by the deposition of asphaltenes in the production strings and surface production facilities, requiring periodic cleanup and treatment operations. In South and East Kuwait, all the wells in the Marrat reservoir were closed from 1998 to avoid further drop in the reservoir pressure, which had already dropped close to the AOP (the present reservoir pressure is around 8,400 psi and AOP ranges from 5,500 psi to 6,700 psi). Further reduction in reservoir pressure below the AOP could cause asphaltene deposition in the reservoir itself and result in formation damage. The decision was made to produce the wells only after a comprehensive development plan for reservoir pressure maintenance with implemented water injection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.