Magnetorheological fluids for oil and gas well application

textCement is used in oil and gas wells to support the casing and prevent fluid migration between formations. Incompetent cementing in a well and the potential subsequent failure of zonal isolation is a significant concern in the oil and gas industry. Insufficient zonal isolation could cause fluid migration resulting in water aquifer contamination and loss of control of well pressure, shortening the life of wells and increasing the risk of well control incidents, which could result in loss of life, economical loss and environmental damage. To achieve good cementation and guarantee zonal isolation during the lifetime of the well, significant technical challenges need to be overcome. Such challenges are associated with guaranteeing proper fluid-cement displacement, preventing gas migration, and maintaining cement integrity during all phases of well life (drilling, completion/stimulation, production, abandonment). Magnetorheological (MR) fluids (cement-based or non cement-based) can potentially be used to tackle these challenges for applications in oil and gas wells. The rheological properties and flow direction of MR fluids can be controlled by the application of a magnetic field. During the primary cementing process, it is important to displace the drilling fluid and spacer fluid out of the annulus with cement in order to obtain enough strength after cement hydration. This study shows that by applying a magnetic field, the MR cement-based fluid can be guided to achieve more uniform displacement and to increase the displacement efficiency. The results also show that an MR fluid can be used as a flow prevention seal and has the ability to hold pressure, due to its instantaneous stiffening effect when the magnetic field is applied. This can be applied to avoid or remediate annular fluid flow and gas migration, form temporary top-, bottom- or straddle packers, and combine with BOPs for instantaneous pressure control. During the production of a well, the cement in the annulus can experience various severe conditions, which can lead to cracking, de-bonding and shear failure of the cement. The magnetic properties of MR cement-based fluid provide a possible way to evaluate the quality of cement, detect cracking in cement and monitor the health of the cement annulus using non-destructive testing with magnetic methods.Civil, Architectural, and Environmental Engineerin

Optimization of Gas Well Completion and Production Practices.

In water drive gas reservoirs, wells can be completed with a long perforated interval and produced at high rates to minimize abandonment pressure and maximize recovery. Alternatively, the perforations can be limited to the top of the productive interval and the well produced at a low rate in an effort to prevent coning which results in high abandonment pressures if the strength of the aquifer is adequate to support reservoir pressure. This study uses a reservoir simulation coning model to evaluate these two conflicting completion and production practices. The impact of completion interval, gas production rate, and reservoir permeability were evaluated. Ultimate gas recovery was found to be largely insensitive to variations in perforated interval and production rate in high permeability systems. Ultimate water production, however, was found to increase at high gas rates and lengthened perforated intervals. In lower permeability systems, ultimate gas recovery was found to increase significantly as production rates were increased, while ultimate water production was actually observed to fall. Sensitivity analysis of vertical to horizontal permeability ratio, fluid density contrast, relative permeability, and formation dip did not alter these conclusions. The conclusion that elevated production rates can be expected to have no detrimental impact on ultimate gas recovery suggests that gas rates should be maximized in low water disposal cost situations. This finding favors the completion of an interval sufficiently long to maximize production rate and thereby insure that gas recovery and present value of gas reserves are maximized. In high water disposal cost situations, however, it should be recognized that this strategy might result in elevated water production in high permeability systems

Investigate a Gas Well Performance Using Nodal Analysis

Gas condensate well has unique reservoir characteristics and ups and downs in well behaviour affect the production rate significantly. A proper optimization can reduce the operating cost, maximize the hydrocarbon recovery and increase the net present value. Well level optimization can be achieved through optimizing well parameters, such as wellhead, tubing size, and skin factor. All of these factors have been investigated using a real field of Thrace Basin and PROSPER simulation program. The history matching data are validated to identify the future performance prediction for the same reservoir deliverability following the period changes. Therefore, predicted results are compared and validated with measured field data to provide the best production practices. Moreover, the results show that the skin factor has a large influence on the production rate by 45% reduction. The reduction in the reservoir pressure declines the production rate dramatically resulted in 70% decline. While manipulating the wellhead pressure shows minor decline compare to tubing size that does not show any significant change to production rate

Evaluation of skin factor from single-rate gas well test

Skin factor is generally used as an indicator for well flow efficiency and the criterion for performing stimulation treatment to improve well productivity. This skin factor is a composite factor and should be divided into its different components in order to evaluate near-wellbore damage. Therefore, the total skin factor obtained from a gas well pressure transient test has two primary components, rate-independent and rate-dependent skins. Both of these skin factors can be determined directly from the interpretation of pressure transient well tests if several transient tests are performed at different rates. However, the multi-rate tests are time consuming and expensive. It is advantageous to estimate the rate-independent skin factor from a single rate test.;In order to obtain a reliable value for the rate-independent skin from a single-rate test, the rate dependent skin must be evaluated independently. The rate-dependent skin depends on the coefficient of inertial resistance, beta and other parameters. A number of correlations relating beta to permeability are available in the literature. These published correlations are derived from limited set of laboratory measurements on various porous media and do not provide consistent results. Alternatively, beta can be determined from the results of the multi-rate well tests using recorded field data.;The main objective of this study is to generate a dependable and simple technique for estimating the true skin factor from the single rate well tests, such as build-up or fall-off tests, on gas wells. More specifically, the objective is to develop a correlation for beta from field data. Since, the correlation of turbulence factor, beta and permeability, k cannot be applied universally to all reservoirs, so the reservoir-specific correlations will be further developed.;The well tests from several wells in the same reservoir were available and several field-specific correlations for beta were developed. The comparison of skin factor determined from these correlations against the skin factors determined from the well test data indicated that reservoir-specific correlations for beta provide accurate and consistent results