PETROLEUM ENGINEERING PROJECT TOPICS AND MATERIALS

A multi-rate test may be characterized by a series of constant flow rates, or uncontrolled variable rate. In fact, pressure build-up testing is a special type of multi-rate well test. The flow meters can aid in the design of both kinds of tests, variable or constant flow rates, and as a direct consequence more accurate analysis and results of their interpretation can be obtained. The approach presented here is based on the assumption that the system is infinite-acting and the logarithmic approximation to the line source solution of the diffusivity equation is applicable. The pressure behaviour caused by a variable flowrate is given by the principle of superposition with time.

Hole cleaning relying on viscous fluids in laminar flow for drilling has proved to be inefficient because of the inability to rotate the string to agitate bedded cuttings. Alternatively, a high fluid flow to induce turbulent flow regime is more effective for hole cleaning, but difficult to achieve because of high friction pressures in the drillpipe. Therefore a bed of cuttings is almost always present in non-vertical boreholes. For laminar flow, the distance that a particle will travel (downstream) before it falls across the annulus clearance can be calculated using Stokes’ law and the local viscosity while flowing can also be calculated. This analysis may be easily applied to optimize mud selection and wiper trips. Applying this model to high low-shear rate-viscosity (LSRV) gels shows that they may perform well inside casing but are expected to do a poor job of hole cleaning in a narrow openhole horizontal annulus without rotation.

Every simulation study is a unique process, starting from the geological model and reservoir description to the final analysis of recovery factor optimizations. In petroleum engineering area, numerical reservoir simulators are often employed to obtained meaningful and reliable solutions for most actual cases due to extreme complexity of reservoir systems. In this work, a three-dimensional numerical reservoir simulator is developed for expansion-drive reservoirs. The governing equation is discretized using finite difference approach; conjugate gradient method with the aid of MATLAB 9.0.0R code is used to solve the system of linear equations to obtain reservoir pressure for each cell, until bubble point pressure is reached; cumulative production at bubble point is computed as sum of expansion from each cell and oil production rate is determined at each time step. The average reservoir pressure is determined as a weighted average based on the stock tank oil that is left in the reservoir, and finally the recovery factor at the bubble point pressure is computed.

This study presents an approach to well placement and production in a green field. A 3D static model of the green field was built using geostatistical techniques to distribute the various model petrophysical properties such as porosity, thickness, and permeability in order to provide reliable reservoir description for dynamic modeling. A dynamic model was constructed to evaluate various reservoir development problems, including well placement, number and types of wells to be drilled in the green field. The drilling of both vertical and horizontal wells was considered in the analysis. Finding the optimal length of the horizontal well to be drilled in order to maximize oil recovery and to properly develop the reservoir was considered a significant problem to address. A sensitivity analysis was carried out to evaluate the impact of horizontal well length on oil recovery. The vertical to horizontal permeability anisotropy (kvkh) was also studied in this work.

Different treating methods thus exist in the petroleum industry for demulsification of crude oil. They include thermal methods, mechanical methods, electrical methods and chemical treatment.8 In general, these methods are interrelated. Applying heat to the emulsion reduces the viscosity of the oil and increases the water settling rates. It also results in the destabilisation of the rigid films caused by interfacial viscosity. Application of heat for emulsion breaking should be based on an overall economic analysis of the treatment facility. Furthermore, some of the mechanical equipment available in the breaking of oilfield emulsions include free-water knockout drums, phase separators etc. High voltage electricity is also often used for breaking emulsion.6 It is generally theorized that water droplets move more rapidly when induced with an electric field, and hence collide with each other, and coalesce. The distance between the electrodes in some designs- is adjustable so that the voltage can be varied to meet the requirement of the emulsion being treated.1 By far; the most common method of emulsion treatment is adding chemicals.

The scope of this work was to make detailed analysis of phase distribution in a horizontal pipe. This detailed analysis has been successfully carried out. Data obtained from wire mesh sensor (WMS) were used for the analyses. The operating fluid considered was an air/silicone oil mixture within a 6 m horizontal pipe with internal diameter of 0.067 m. The gas superficial velocities considered spans from 0.047 to 4.727 m/s, whilst liquid superficial velocities ranged from 0.047 to 0.4727 m/s. The wire mesh sensor (WMS) data obtained consist of the average cross-sectional and time average radial void fraction sensor with an acquisition frequency of 1000 Hz over an interval of 60 s. For the range of flow conditions studied, the average void fraction was observed to vary between 0.38 and 0.85. An analysis of the results shows that the major flow patterns observed in this study were found to be in slug and smooth stratified flow regime with the slug flow been the dominant one.

A major drawback of directional and horizontal well drilling is the numerous complex computations required to be done ahead of time before drilling resumes and also during drilling operations (Sawaryn, 2005). These computations become very stressful and more complex when done manually. The programs available in the market used for these computations are usually very expensive to acquire, but the development of a user-friendly Excel Spreadsheet program which employs the Minimum Curvature method for wellpath planning would help minimize the stress and time in executing these complex computations. More importantly, an Excel Spreadsheet program is very flexible and can easily be modified or updated at any point in time to meet the needs of the industry.

This thesis presents a methodology for building and ranking equiprobable realizations of the reservoir by both static and dynamic measures. Sequential Gaussian Simulation was used to build 30 realizations of the reservoir. The volume of oil originally in place, which is a static measure, was applied in ranking the realizations. Also, this study utilizes Geometric Average Permeability, Cumulative Recovery and Average Breakthrough times from streamline simulation as the dynamic measures to rank the realizations. A couple of realizations selected from both static and dynamic measures were used to conduct a successful history match of field water cut in a case study.

Overpressures are subsurface fluid pressures that are greater than the pressures expected under normal hydrostatic conditions. Overpressured reservoirs are abundant in sedimentary basins throughout the world. In the United States, abnormally-pressured gas reservoirs are concentrated in the Gulf Coast, Anardako Basin, Delaware Basin and Rocky Mountain Area. In the Middle East, overpressured gas reservoirs are found in Iraq, Iran and Saudi Arabia. These reservoirs commonly produce light oils and gases and require special evaluation techniques. Prior knowledge of the possibility of encountering overpressures at particular subsurface depths is important when exploring for oil and gas. This is because the presence of higher-than-normal pressure increases the complexity and cost of drilling, well-completions and production operations. Additionally, the effect of overpressures on reservoir behavior must be recognized when predicting performance.

Nonlinear Optimization, also known as nonlinear programming has proven itself as a useful technique to reduce costs and to support other objectives, especially in the refinery industry whereas linear optimization is a method applicable for the solution of problems in which the objective function and the constraints appear as linear functions of the decision variables. The constraint equations may be in the form of equalities or inequalities. Furthermore, it had been used to determine the most efficient way of achieving optimal outcome for example, to maximize profit or to minimize cost in a given mathematical model. It can be applied to numerous fields like business or economics situations, and also in solving engineering problems. It is useful in modeling diverse types of problems in planning, routing, scheduling, assignment and design.