Flowline Design Research Articles

Overview: Deepwater Exploration and Production (June 2006)

Deepwater oil and gas projects are some of the most challenging of human endeavors. The sheer size of many of these efforts—and the impressive new technologies used—is truly amazing. Deepwater projects also entail great risk, however, and things sometimes do go wrong. Of course, things go wrong on all types of projects, but the deepwater environment itself and the large-scale nature of many projects exacerbate the severity of any problem. Costs can increase to many times the budget, the details associated with implementing new technology can be overwhelming, and schedules easily can slip enough to jeopardize the commercial success of the project. Some problems are related to project decisions that are made to maintain schedule before all of the needed facts are available. On a complex project, decisions are made that, in retrospect, are clearly wrong. Other problems arise simply as a result of mistakes made by the project management or technical teams. To be successful, the project team must be willing to recognize mistakes as early as possible and take corrective action. Knowledge of how mistakes were addressed on previous projects, both successfully and unsuccessfully, can be invaluable in selecting an appropriate corrective action. Examining lessons learned from previous projects provides one of the most important methods for improving project execution. Barry LePatner, an attorney testifying before a U.S. House of Representatives Science and Technology Committee on disclosure of information from building failures, made the following observation: "Good judgment is usually the result of experience. And experience is frequently the result of bad judgment. But to learn from the experience of others requires those who have the experience to share the knowledge with those who follow." The sharing of project-management lessons learned on deepwater projects, however, is a relatively recent development. Project management is as important to the success of deepwater projects as technology. The continued sharing of project-management lessons learned would help project teams meet the myriad nontechnical challenges associated with deepwater projects. Deepwater Exploration and Production additional reading available at the OTC Library: www.otcnet.org OTC 17971 "Albacora Leste Deepwater Field: Improvements on Well Construction," by E. de Melo Sanches, Petrobras, et al. OTC 17806 "Combined Effect of Flowline Walking and Riser Dynamic Loads on HP/HT Flowline Design," by M.S. Brunner, Technip U.S.A., et al. OTC 18311 "K2 Topside Facilities—Design Challenges," by F. Colbert, OFD Engineering LLC, et al. OTC 17655 "The Significance of Gas Hydrate as a Geohazard in Gulf of Mexico Exploration and Production," by M.A. Smith, U.S. Dept. of the Interior, Minerals Management Service, et al.

A machine-to-loop assignment and layout design methodology for tandem AGV systems with multiple-load vehicles

In this paper, we propose a design methodology for tandem Automated Guided Vehicle (AGV) systems with multiple-load vehicles. Our goal is to devise a design methodology that can achieve the following objectives in multiple-load tandem AGV designs. The first objective is to achieve the workload-balance between vehicles of different loops. The second objective is to minimize the inter-loop flow. The final objective is to minimize the flow distance. To achieve these objectives, the following problems are studied. First, we conduct simulations to study the relationship between a vehicle's load-carrying capacity and work capacity. This relationship is then considered in the second problem, i.e. the problem of determining the machine content of each loop. A two-stage machine-to-loop assignment method is proposed for solving this problem. At the first stage, an initial machine-to-loop assignment is generated. This initial assignment is then improved at the second stage using Simulated Annealing (SA). The third problem is the problem of determining the layout of machines in each loop. A flow-line design method and SA are adopted for solving this problem. The fourth problem is the layout problem of guide-path loops. To solve this problem, a famous layout method found in the literature is adopted. The last problem includes the problem of determining the best orientation of each loop and the problem of finding the best places to set up transfer stations between adjacent loops. A mathematical programming model that can solve them simultaneously is proposed. Simulations are then conducted to verify the design, and to show that the proposed design methodology is indeed capable of producing good and satisfactory tandem AGV designs with multiple-load AGVs. Finally, it is our hope that the knowledge learned from this study can help us have a better understanding of multiple-load AGV systems and allow us to have successful implementations of similar systems in practice.

Viscosity of ‘live’ water-in-crude-oil emulsions: experimental work and validation of correlations

A method for measuring emulsion viscosity under pressurized (1–100 bar) and temperature-controlled flow conditions is described. It makes use of a flow simulator shaped as a hollow wheel. As the wheel is rotating, the liquid inside will have a relative motion in the opposite direction of the rotation. The torque acting on the wheel shaft is measured and transformed, via a calibration model, into the viscosity of the fluid. The method has been applied to water-in-oil emulsions with several live North Sea crude oils with saturation pressures up to 100 bar and water cuts in the range 0–90%. The method is shown to be a useful way of obtaining estimates of emulsion viscosity for live oil systems in a relatively small scale apparatus. Even though the crude oils studied were rather different and had very different viscosities, the relative viscosities as a function of water cut up to at least 60% showed small variation and might be represented by a general ‘master curve’. The relative viscosities obtained experimentally have been compared to a temperature-dependent Richardson-type correlation [Rønningsen, H.P., 1995. Correlations for predicting viscosity of W/O-emulsions based on North Sea crude oils. Proc. SPE Int. Symp. Oil Field Chem., Houston, TX, USA, SPE 28968], and three other correlations proposed by Mooney [J. Colloid Sci. 6 (1951) 162], Pal and Rhodes [J. Rheol. 337 (1989) 1021] (P&R) and Pal [J. Colloid Interface Sci. 231 (2000) 168], respectively. Overall, when being tuned to measured data, the P&R correlation gives the best match, closely followed by the Mooney correlation, but for low and medium water cuts, the Rønningsen correlation is comparable. This correlation does not require any measurements for tuning. Although it may be slightly conservative at low to medium water cuts, and somewhat optimistic at very high water cuts, for practical purposes in design of flow lines, it provides a reasonably accurate first estimate of the effective liquid phase viscosity. The recent correlation of Pal [J. Colloid Interface Sci. 231 (2000) 168] was found to be extremely sensitive to the choice of tuning point and, thus, to be rather inaccurate either at low water cuts or high water cuts.

ARTIFICIAL NEURAL NETWORK MODEL FOR ACCURATE PREDICTION OF PRESSURE DROP IN HORIZONTAL AND NEAR-HORIZONTAL-MULTIPHASE FLOW

ABSTRACT Accurate prediction of pressure drop for multiphase flow in horizontal and near horizontal pipes is needed for effective design of flow lines and piping networks. The increased application of horizontal wells further signified the need for accurate prediction of pressure drop. Several correlations and mechanistic models have been developed since 1950. In addition to the limitations on the applicability of all existing correlations, they all fails to provide the desired accuracy of pressure drop predictions. The recently developed mechanistic models provided some improvements in pressure drop prediction over the empirical correlations. However, there is still a need to further improve the accuracy of prediction for a more effective and economical design of wells and surface piping networks. This paper presents an Artificial Neural Network (ANN) model for prediction of pressure drop in horizontal and near-horizontal multiphase flow. The model was developed and tested using field data covering a wide range of variables. A total of 225 field data sets were used for training- and 113 sets data for cross-validation of the model. Another 112 sets of data were used to test the prediction accuracy of the model and compare its performance against existing correlations and mechanistic models. The results showed that the present model significantly outperforms all other methods and provides predictions with accuracy that has never been possible. A trend analysis was also conducted and showed that the present model provides the expected effects of the various physical parameters on pressure drop.

Characterisation of a heavy mineral-bearing sample from India and the relevance of intrinsic mineralogical features to mineral beneficiation

Iscor has developed a standard method to deal with heavy mineral-bearing sand samples in order to characterise and evaluate such samples. The aim of this paper is to present the methodology of the standard method, using a sample from a heavy mineral-bearing beach sand deposit in India as a case study. The first stage of the standard method involves preparation of the original sample to produce fundamental data, as well as to provide suitable samples for mineralogical investigation. During sample preparation the sample was deslimed, sink-floated and subjected to magnetic separation to produce four fractions, namely high susceptible magnetics, magnetics, magnetic-others and non-magnetics. Stage 2 of the method involves mineralogical investigations of these fractions in order to characterise the original sample. The investigation includes the systematic analyses and descriptions of the samples, using techniques such as XRF and XRD analyses, microscopic descriptions of the minerals and semi-quantitative analyses. Finally, based on results obtained in the previous stages, the sample is then evaluated to decide whether the specific deposit merits furthers interest or not. Applying the methodology of this standard method to characterisation of the Indian sample, some important aspects were revealed. It became evident that the mineralogical and chemical compositions of the high susceptible magnetic, magnetic and magnetic-other fractions are similar in that these fractions consist mainly of ilmenite with the high susceptible magnetic fraction also containing appreciable amounts of hematite. Detailed microcopy revealed that the widespread occurrence of ilmenite in all three these fractions can be explained by variations in weathering and textural properties resulting in heterogeneous grains with varying magnetic susceptible properties. Furthermore, it was found that zircon is the main valuable mineral present in the non-magnetic fraction while considerable amounts of rutile are also present. Unfortunately, the presence of undesirable amounts of sillimanite increases the impurity levels of this fraction. However, with this being known beforehand, proper beneficiation flowline design can “clean-up” the fraction to acceptable levels. Characterisation of these intrinsic mineralogical features plays an important role in understanding the behavior of the minerals during beneficiation and the designing of optimal beneficiation routes. Finally, semi-quantitative mineralogical data were used to calculate the mineral composition of the sample, and together with chemical analyses, supplied a very useful and practical data set to use in evaluation of the original sample.

Stability Analysis of Stratified Oil/Water Flow in Inclined Pipelines

Summary A theoretical study was conducted to investigate flow-pattern transitions in slightly inclined pipelines carrying oil/water mixtures. Two criteria obtained in the linear-stability theory of stratified oil/water flow were used to predict the transition from a stratified-to nonstratified-flow pattern. A comparison of theoretical transition boundaries with published experimental data for horizontal and inclined pipes (±1° and ±5°) was performed. The study revealed that pipe inclination has a significant effect on the stratified-flow region. The results obtained can be useful for the design and operation of crude-oil flowlines and directional wells.

Elliptic ray bundles in three-dimensional geometry for nonimaging optics: a new approach

A new method to obtain elliptic ray bundles in three-dimensional geometry is presented. This type of bundle is of special interest in nonimaging optics because the only known three-dimensional ideal concentrators with homogeneous media transmit elliptic bundles. First, we reformulate the condition for a bundle to be elliptic; that is, the rays passing through any point of the space form a cone with an elliptic base. The solution found includes all the elliptic bundles obtained by other methods as a particular case. Second, we look for the concentrators defined by the new elliptic bundles with the flow-line design method of nonimaging optics. Most of these bundles do not generate new devices but are transmitted ideally through the already known three-dimensional ideal concentrators.

Application of Lorentz geometry to nonimaging optics: new three-dimensional ideal concentrators

A new family of three-dimensional ideal nonimaging concentrators with rotational symmetry is presented. The flow-line concentrator and the cone concentrator are particular cases of this family. First, we looked for elliptic bundles of rays, i.e., bundles such that the subset of rays passing through any point of the space forms a cone with an elliptic base (this search was done with the Lorentz geometry formalism.) Second, the concentrators, defined by their reflectors and receiver shapes, were derived from these elliptic bundles with the flow-line design method.

Two sequence-pattern, matching-based, flow analysis methods for multi-flowlines layout design

Abstract In optimizing the layout design of a multi-product assembly environment, the analysis of the material flow is a vital ingredient. In a multi-product production environment, products are usually grouped together into families. Products of the same family group usually involve similar operations; however, it is common to see some difference in the operations and the operational sequences among these products. The design technique for the layout of multi-product flowlines should be able to resolve the difference among the operation sequence of these products. The ideal material flow in a good layout design should be mostly in-sequence flow. In-sequence flow usually has the benefits of smaller flow distance, easier control of the production process and easier material handling. This paper proposes two flow analysis methods that are designed to provide a better flow analysis for the design of multi-products flowline. The first method adopts the traditional line structure for analysis. The second metho...

Completion of a Deep, Hot, Corrosive East Texas Gas Well

Summary A 19,011-ft [5795-m] wildcat in Houston County, TX, was successfully completed in March 1984. It tested the Lower Cotton Valley sand, which produced 14.5 MMscf/D [411×103 std m3/d] at a flowing tubing pressure of 8,671 psig [59.8 MPa]. The produced gas contained 4.9% CO2 and 24 ppm H2S. A bottomhole temperature (BHT) of 400°F [204°C] and bottomhole pressure (BHP) of 17,000 psig [117.2 MPa] intensified the corrosion potential. Tubular corrosion protection was provided by a 13% Cr production liner and a combination tubing string of 13 and 22% Cr alloys. The high pressure necessitated a 6,200-psig [42.7 MPa] underbalance liner top test. This paper outlines the completion and the supporting logic. It includes a discussion of the liner cementing, hole displacement, packer selection, tubing design, perforating, wellhead selection, and flowline design.

Incompletion costs versus labour efficiency on the fixed-item moving belt flowline

This paper describes the operation of assembly lines where items are rigidly attached to a moving conveyor bolt and where the processing stations are confined within fixed boundaries. Another mechanical method of product transfer, namely indexing, is also discussed, Both Monte Carlo simulation models and two industrial examples yield convincing evidence that for good flowline design the ratio of on-line inventory to stations should be greater than unity. Such a condition would effectively discriminate against the use of stochastic assembly line balancing techniques, although they have been developed specifically for such systems. In addition, the results confirm that the most economic way of operating these lines is to sot a pace that is fast enough to generate a small proportion of unfinished items.

The Elimination of Interference Time Caused by the Variation of Operation Time : The Solution of Problems as to the Design of Flow Line in Job Shop (Part 1)

The Elimination of Interference Time Caused by the Variation of Operation Time : The Solution of Problems as to the Design of Flow Line in Job Shop (Part 1)

On the Analogy of Set-up : The Solution of Problems as to the Design of Flow Line in Job Shop (Part 2)

On the Analogy of Set-up : The Solution of Problems as to the Design of Flow Line in Job Shop (Part 2)