S. Mustafiz

No-Flare Design: Converting Waste to Value Addition

Abstract A common practice among all oil producing companies is to burn off any unwanted gas that liberates from oil during production. Although this process ensures the safety of the rig by reducing the pressures in the system that result from gas liberation, it is very harmful for the environment. The implementation of a no-flare design will have a great impact in reducing the emissions from production. The problem of no-flare design is comprised of the separation of gas, solid and liquid. In this article, various options in achieving a no-flare process are discussed. While advances have been made in separating liquid and gas, challenges are abound when it comes to separation of gases. Unless this is done, the capture and use of gases cannot be performed with any appreciable efficiency. Various novel options for separation processes are highlighted. Membrane separation will be highlighted as well since it offers the greatest hope for a no-flare design in this regard. In addition to effective separations, value added end products will be discussed. This essentially means the usage of the separated wastes. Various methods of fines usage as well as low quality gases will be outlined. Novel methods to purify produced waters are also examined. Indeed, a no-flare design coupled with value added end products is imperative for the future of an environmentally appealing oil and gas industry.

State-of-the-art Petroleum Reservoir Simulation

Abstract Today practically all aspects of reservoir engineering problems are solved with a reservoir simulator. The use of the simulators is so extensive that it will be no exaggeration to describe them as “the standard.” The simulators enable us to predict reservoir performance, although this task becomes immensely difficult when dealing with complex reservoirs. The complexity can arise from variation in formation and fluid properties. The complexity of the reservoirs has always been handled with increasingly advanced approaches. This article presents some of the latest advancements in petroleum reservoir simulation. Also discussed is the framework of a futuristic reservoir simulator. It is predicted that in the near future, the coupling of 3-D imaging with comprehensive reservoir models will enable one to use drilling data as input information for the simulator creating a real-time reservoir monitoring system. The time is also not far off when a virtual reservoir will be a reality and will be able to undergo various modes of production schemes. The coupling of ultra-fast data acquisition system with digital/analog converters transforming signals into tangible sensations will make use of the capability of virtual reality incorporated into the state-of-the-art reservoir models. In their finest form, the reservoir simulators must be intelligent enough to integrate environmental impacts of enhanced oil recovery (EOR) processes into the technical and economical feasibility of different EORs. The economics, however, should respect both short-term and long-term impacts of oil production in order to claim ensure technical accuracy as well as rendering petroleum production schemes truly sustainable.

Numerical Investigation of the Prospects of High Energy Laser in Drilling Oil and Gas Wells

Abstract Lasers are expected to provide a less expensive alternative to conventional machining and have found wide spread use in many industries. However, the physical phenomena involved in many laser applications are not fully understood. A better and more quantitative understanding of the physical mechanisms governing these phenomena will diminish the need for extensive trial and error experiments. Most of the theoretical models available in the literature have dealt with quasi-steady material removal using a continuous wave laser. This article presents a numerical model to predict the transient thermal behavior process of rocks under the influence of a pulsed laser. A wide range of parameters were considered in this study, the laser powers were varied from 0.1 to 100 kW and the lasing time was varied between 1 and 100 s. One of the results presented in this article shows that limestones consume less energy per unit volume of material removed as compared to sandstones. A comparison between the findings of this numerical study and published experimental data is also presented and shows a qualitative agreement. Finally, it is shown that numerical modeling can be useful in scaling up laboratory results to field applications.

The Effects of Linearization on Solutions of Reservoir Engineering Problems

Abstract The natural processes are nonlinear. Each property is affected by the variation of other properties existing in a process. However, it is necessary to impose some simplification and linearization in order to obtain numerical description for the majority of the problems in applied sciences. The simplification may take place in mathematical formulation and/or during numerical evaluation of a problem. This article investigates the effects of nonlinearity in the flow equation of a petroleum reservoir. The petroleum industry is well known for its intense use of computer models that employ various levels of linearization. Because the computational operation is repeated numerous times for billions of discrete grid blocks, any systematic error induced by linearization can have profound impact on predicted results. In this article, the dependency of the fluid and formation properties on the variation of the reservoir pressure is evaluated during the solution of the flow equation using the engineering approach. The continuous functions and piecewise functions are applied to approximate the variation of viscosity, fluid formation volume factor, and permeability. The computational results are compared with the linearized approximation for the variation of these properties. The approximation that imposes linearization on the mathematical formulation is also evaluated. The continuous nonlinear functions are not appropriate to approximate the variation of a process property. The best approximation may be obtained using the piecewise function such as a spline function of different orders.

Lasing into the Future: Potentials of Laser Drilling in the Petroleum Industry

Abstract The need for a new method of drilling oil and gas wells is immense. Current drilling techniques used were developed at the beginning of the last century. Many problems persist with this method including downtime due to dull bits, the lack of precise vertical or horizontal wells and formation fluid leakage during drilling due to the lack of a seal around the hole. Laser drilling is a new technology that has been proposed as a method to eliminate the current problems while drilling. Although experiments for laser drilling were conducted in the 1960s and 1970s, it is only recently that this research area has been redirected to the oil and gas industry. This article reviews the benefits of laser drilling, current laser types, and the experimental work that has been conducted. The experimental work conducted thus far is performed with several different lasers such as the US Armys MIRACL and the US Navys COIL. The data that was generated by these studies was executed on several types of cores including sandstone, limestone, and shale. The effect that lasing has on porosity and permeability as well as the effect of saturation and pressure on lasing was determined. The work conducted shows that a great future potential awaits the oil and gas industry with laser drilling.

A New Technique for Cleaning Horizontal Wellbores

Abstract The plugging of horizontal wellbores can lead to significant loss of productivity and can nullify the benefit of a horizontal wellbore, which is expensive to create. Cleaning horizontal wellbores is a formidable challenge. The problem is particularly complex for heavy oil formations that show asphaltene, sand, and other difficult-to-remediate problems. This paper aims at developing a new technique that can effectively clean up a horizontal wellbore without requiring expensive workovers. The technique involves the use of ultrasonic treatment coupled with foam treatment. Initial experiments show that ultrasonic treatment can reduce plugging in two ways—the first is the reduction in oil viscosity (especially in the presence of asphaltic crudes) and the second is the ability of ultrasound to keep particles in suspension. The second effect can be due to the generation of microbubbles. The process is coupled with in situ generation foam. In order to generate foam, a particular type of surfactant is chosen from a selection of a wide range of surfactants supplied by the service companies. While the design of the device that couples both these effects needs to be optimized, an initial series of experiments shows good promises.

Adomian Decomposition of Buckley-Leverett Equation with Capillary Effects

Abstract Petroleum reservoir engineering problems are known to be inherently nonlinear. Consequently, solutions to the complete multiphase flow equations have been principally attempted with numerical methods. However, simplified forms of the problem have been solved some 60 years ago, when the Buckley-Leverett formulation was introduced. Ever since that pioneer work, which neglected the capillary term, this formulation has been widely accepted in the petroleum industry. By using the method of characteristic, the multiphase one-dimensional fluid flow was solved. However, the resulting solution was a triple-valued one for a significant region. For decades, the existence of multiple solutions was considered to be the result of nonlinearity. Buckley and Leverett introduced shock utilizing the concept of material balance, and, two decades later, when numerical solutions were possible, it was discovered that the triple-value problem disappeared if the complete flow equation, including the capillary pressure form, is solved. Numerical methods, however, are not free from linearization. In fact, every numerical solution imposes linearization at some point of the solution scheme. Therefore, a numerical technique cannot be used to definitively state the origin of multiple solutions. In this article, a semi-analytical technique, the Adomian decomposition method (ADM), capable of solving nonlinear partial differential equations without any linearizing assumptions, is used to unravel the true nature of the one-dimensional, two-phase flow. Results show that the Buckley-Leverett shock is neither necessary nor accurately portrayed in the displacement process. By using the ADM, the solution profile observed through numerous experimental studies was rediscovered. This article opens up an opportunity to seek approximate but close to exact solutions to the multiphase flow problems in porous media.

The Effect of Irradiation on Immiscible Fluids for Increased Oil Production With Horizontal Wells

Oil recovery using horizontal wells gives an undeniable benefit to the petroleum industry. One of the problems of using this method is that the wells can plug due to pressure and temperature changes. The components of crude oil such as asphaltene and paraffin wax can precipitate in the horizontal section of the well causing a loss of productivity and profit. Microwave or irradiation has been proposed to remove these precipitates remotely. The effect of microwaves on crude oil properties has been studied and a numerical model is presented to gain an understanding of the effect of the rise in temperature. These results include temperature increases for various concentrations of crude oil, and paraffin wax under different exposure times. The effect that different media (bentonite and gypsum) has on the temperature of these components has also been studied. By understanding the temperature rise, one can determine the effect that irradiation will have on oil production. Overall, the agreement between experimental and numerical results was acceptable.Copyright

A New Two Phase Extension of Modified Brinkman Formulation for Fluid Flow through Porous Media

In porous media research, Modified Brinkman’s equation is a very recent development. It is important as it incorporates the concept of viscous effect to inertial effect in a fluid flow system when Darcy’s, Forchheimer’s and Brinkman’s terms are brought all together. So far, researchers have developed the modified equation in its two-dimensional forms; however, limited to only one phase. In reality, petroleum reservoirs experience the multiphase conditions. Therefore, the simulation of a multidimensional, multiphase scenario is mostly desired, the highlight of this paper. The paper presents the formulation of two-dimensional, transient pressure and saturation equations for oil and water phases, one equation for each phase. The difference between phases is noticeable explicitly in their respective saturation, permeability, viscosity and velocity terms. The equations are then solved numerically to generate relative permeability curves. The simultaneous solution of pressure and saturation terms in the governing equations required additional relationships: the phase saturation constraint and capillary pressure as function of saturation. Finally, the numerical results are compared and validated with the experimental results. The implication of this study is manifold. The formulated equations including the solution part for the multiphase conditions are new. The new comprehensive model will describe fluid flow in reservoirs prone to high velocity or fractures more accurately than ever described by Darcy’s or other aforementioned equations.Copyright

Modeling Horizontal Well Oil Production Using Modified Brinkman’s Model

Horizontal well oil production has been numerically studied by using the Modified Brinkman’s Model. This model has been used along with the Darcy-Weisbach pipe flow equation in modeling of coupled porous medium/pipe flow. The results include seepage flow rate along the horizontal well, velocity distribution, pressure drop, and production pressure drop between the two ends of the horizontal well. They have been compared with those from Darcy model. It is found that when the fluid’s viscosity is low, there is a big difference between the results from the two models. However, when the fluid’s viscosity is high, the difference tends to vanish. In addition, two striking findings have been observed: (a) the curves for the distribution of the seepage flow rate along the pipeline are more flat than that from Darcy model. However, a higher viscosity makes the curve more uneven. This reverses the trend from Darcy model. (b) The velocity in the pipe is more uniform by MBM than that by Darcy model. The curves of V ~x become more uniform in the pipe when the fluid has a lower viscosity. This again reveres the trend from the Darcy model.Copyright