Maximizing profit with minimal costs is a top priority in the oil and gas industry. With the dynamics of today's oil market, finding economically feasible tools to maximizing the production is vital. Multilateral wells possess the potential of achieving such a goal. To date, different theoretical designs of multilateral wells are proposed in literature. One of the most common designs studied is the fishbone configuration. This configuration maximizes the reservoir contact and thus the productivity of the well. While the merits of the application of multilateral wells are well documented, an understanding of the best operating conditions for the use of multilateral wells is rare thus we answer cogent questions related to the optimization of multilateral wells under different reservoir conditions and well design parameters. To answer such questions, Design of Experiment (DOE) and Response Surface Methodology (RSM) was utilized. Selected factors to be optimized are the number of laterals, length of horizontal sections of laterals, correlation lengths for heterogeneity indication, reservoir thickness, and permeability anisotropy. These factors were chosen based on literature search, perceptions and deliberations while the objective function is the cumulative oil production. Several experiments were conducted using extensive three dimensional fine scale numerical simulations and the Box Behnken response surface methodology was used to derive the response surfaces. Single effects and interaction plots are made to show the interactions between parameters and the effect of these parameters and interactions on the objective function. Results show a high dependence of productivity on the horizontal section length and reservoir thickness. This implies that candidate reservoirs for the application of fishbone multilateral wells should possess larger thickness. However, where the reservoir is thin production can be improved using longer horizontal sections. The outcome of this study indicates the importance of the horizontal section and lateral lengths on a fishbone multilateral well productivity from the same reservoir. This study provides a template for decision making in field development operations thereby reducing uncertainties and maximizing gains.

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This research work predicts capillary pressure curves at primary drainage from the transverse T2 relaxation times of the NMR pore size distributions with ninety percent accuracy, which could do the trick in reservoir applications. The capillary pressure-water saturation curves are important instructions to reservoir simulators for predicting the dynamic properties of the reservoir as well the fluid saturations at different depths. This study originated from the challenges in forecasting the initial saturations from an NMR logged well. The procedure is a simple and non-damaging construction of capillary pressure curves from plug samples measurements. Dynamic rock typing was used to assign the capillary pressure data to different layers in the reservoir. Laboratory Nuclear Magnetic Resonance (NMR) equipment has been proven to produce information on pore size distribution and varieties of methods was found in the literature to predict capillary pressure curves from borehole NMR logs. The proposed idea of integrating drainage capillary pressure from centrifuge to T2 distributions from NMR enables rapid synthesis of capillary pressure from plugs and interpretation of logs. A scaling factor k, is adopted in the T2-Pc conversion. The optimum scaling factors for most research work is built upon the results. Water saturation at certain pressures, is often estimated from capillary pressure curves. It can therefore be argued that the perfect procedure of estimating the best scale factors is to recreate the saturations by the capillary pressure curves developed from NMR. In this research work, the range of pressures and T2 relaxation time was 0 – 500 psi and 1 – 10000 ms respectively. Due to different geological facies usually described by the capillary pressure curves of different formations, the capillary pressure curves of the completely cored reservoir were reconstructed to get the average scaling constant, k of 4 psi.s with a low standard deviation of 0.02. The capillary pressure versus T2 curve tend to fit a power regression with a coefficient of determination of R2= 1, signifying that the regression line analysis fits perfectly with the data for the 18 core samples. With the T2-Pc conversion established, the capillary pressure data can be predicted continuously in the whole section of the reservoir. The procedure is more accurate compared to others since it takes cognizance of the pore structure from NMR distribution, and it is applicable to T2 distributions estimated at various water saturations. Previous methods are applicable to 100% brine saturated plugs, which nullifies their predicted capillary pressure curves.

In the shadow of low oil prices, it is necessary to develop economically and environmentally friendly solutions. In oil and gas industry, majority of the production stream is water. This water is produced with the hydrocarbon to surface. This requires the separation of the fluids produced and then treating those streams to abide with environmental regulations and clients' specifications. CDOWS (Centrifugal Downhole Oil Water Separator) technology is believed to provide high separation quality, high oil recovery with reduction of operating costs and less surface facilities. The development process involves simulation of tubular centrifuge using a computational fluid dynamics (CFD) software to analyze the parameters affecting separation. After that, an experimental set up is erected which mimics in-well CDOWS. The novel design of the tool involves specially designed weir to collect the oil and water through concentric tube configuration. The parameters tested through simulation include; flow rate, RPM, tubing length, tubing diameter, API and oil/water ratios. The experimental set-up is used to confirm the sepration in the rotating tube as it is made of acrylic material. The CFD model involves a rotating cylinder (tubing) in which oil and water are introduced from the inlet. The feed of oil and water exhibits high centrifugal forces resulting in their separation through and to the outlet of the tubing. The experimental design mimics the actual in-well design which can be implemented in a well. The design can be configured easily to change the tubing parameters. After conducting the studies, a sensitivity analysis using design of experiment approach (DOE) and response surface plots is produced to emphasize on parameters and their interaction effects. Findings include better separation using higher RPM, ID, L, water salinity, API. The most influential factor is RPM which can be controlled and thus will define costs for later stages of the project. This paper presents the first work on CDOWS which is analogous to in-well configuration aiming for a solution with reduced costs.

As production from unconventional (shale) oil and gas rises, large volumes of water are produced as a by-product. These water streams contain a variety of contaminants including: Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Naturally Occurring Radioactive Material (NORM), heavy metals. Treating this water incurs additional costs. Moreover, abiding by environmental regulations set by authorities is the responsibility of the operator. In addition, hydraulic fracturing (fracking) operations consume a lot of water. This paper proposes the use of an online monitoring system to evaluate the water quality, which can be linked to a downstream program to evaluate the profitability of treating this water further. The Water Economic Feasibility Indicator (WEFI) program was also developed to help operators make decisions on the adequate water treatment technologies to employ based on economic parameters.A case study is presented to evaluate the program, which involved using water production data from a field. The results showed that introducing Multi-Effect Distillation (MED) and Vapor Compression Distillation (VCD) technologies to treat the water further yields favorable outcomes. Graphs were plotted, demonstrating the associated costs of MED and VCD. Moreover, the cumulative net present value (NPV) of profit generated from sales of potable water is higher for VCD than MED.Another possible use of this water is agriculture and livestock watering. This lowers the water stress in the region. Findings indicate that it is profitable to process the water to a potable/irrigation level using VCD equipment than to dispose of it, thereby providing net monetary, social, and environmental benefits.