Yingying Wang

Selection of deepwater floating oil platform based on grey correlation

Abstract To select a suitable floating oil platform for a given deepwater oilfield, a method based on grey-correlation theory was proposed and verified. By analyzing factors that may affect selection of deepwater platform, thirteen main factors were chosen. This article also summed up the statistics on 65 deepwater floating platforms (including tension leg platform, deep-draft column type platform, semi-submersible platform, and floating storage mining and unloading device) performing well in the world. With a deepwater oilfield to be developed as a sample, the application of the method was illustrated: Considering the factor series of the given oilfield to be developed as referent series, the relevance between referent series and factor series of each platform in statistics was calculated with grey-correlation analysis, and the optimal platform was identified as the one that had the highest relevance. Two examples proved the feasibility and reliability of the method.

Modeling for the Optimization Evaluation of Layout Scenarios of Subsea Cluster Manifolds Considering Three Connection Types

Based on a connection matrix and a cost matrix, a mathematical model is presented to describe the optimization evaluation of the layout scenarios of subsea cluster manifolds in ocean engineering at the lowest cost. The connection facilities are considered, including jumpers, pipeline end terminations (PLETs), and infield flowlines. The dedicated series-iteration algorithms programed by MATLAB are conducted to solve this complex nonlinear 0‐1 programming problem. Additionally, numerical simulations are performed to demonstrate the validity of the model and the performance of its algorithms. The results show that the proposed model can precisely describe the layout characteristics of cluster manifolds in engineering and the dedicated algorithms are quite robust. Possible layout scenarios with three-to-eight cluster manifolds for 22 subsea wells can be obtained, from which the optimal one with the lowest cost can be found by comparison. This approach can provide quantitative and efficient references to engineers to assist them in making their decisions in the layout of subsea production systems.

A new partition model for the optimization of subsea cluster manifolds based on the new definition of layout cost

The engineering practicability for the partition optimization of subsea cluster manifolds should be improved to provide a broader insight to subsea engineering designers, considering three connection types of jumpers between subsea wells and cluster manifolds. With the jumpers, pipeline end terminations and infield flowlines, this study describes an optimization method by a new definition of the layout cost of a piecewise function. That is different from the layout cost of the square of Euclidean Distance when the connection types are assumed to be straight flowlines without considerations of the connection facilities. A new practical optimization model of the partition of cluster manifolds at the lowest cost is presented and its core algorithm is developed with a program by MATLAB. Meanwhile, the demonstration of the convergence of the proposed algorithm is conducted. The validity of the model is evaluated by the simulation with a random two-dimensional distribution of 20 subsea wells. With the rapid convergence of the algorithm, 20 subsea wells can be partitioned into corresponding two to seven cluster manifolds and three connection types of jumpers in engineering can be obtained exactly by comparisons. In addition, spared well slots on cluster manifolds can be left for the future tiebacks of subsea wells by changing the types of cluster manifolds.

A mathematical solution of optimal partition of production loops for subsea wells in the layout of daisy chains

The daisy chain is one of the main layout types of the subsea production system in the development of deepwater oil and gas fields. The number of production loops, length of subsea pipelines, and partition of subsea wells are the main concerns in pigging loop design, pipeline laying, and flow assurance, which become important factors for the capital and operating expenditures and the risk management of deepwater fields. This article focuses on the basic optimal partition problem of production loops for subsea wells in the layout of daisy chains. It proposes to find the optimal partition method at the lowest layout cost, where a mathematical model is proposed and its dedicated algorithm is developed. Numerical simulations are conducted to evaluate the validity of the proposed model and the performance of the algorithm. The results show that the model can accurately describe the optimal partition problem of daisy chains in practice, and a mathematical solution to the optimal partition can be obtained by the algorithm programmed in MATLAB, which can provide the engineers a quantitative reference for the layout of daisy chains in engineering.

An Exploratory Study on Optimum Layout of the Cluster Manifold

There are four typical layout types for the subsea production system. These include single well tie back, the daisy chain, the template manifold and the cluster manifold. In the early development phase, an appropriate layout type needs to be selected. The layout design of the subsea production system is based on the data of oil and gas fields. Due to many advantages, such as less initial investment, being installed in advance, flexibility for development schedule and so on, the cluster manifold is becoming more popular and has been applied extensively in the layout of deepwater subsea production systems. In this layout type, the number and locations of cluster manifolds, and the connection types between subsea production facilities have a direct effect on the safety, flexibility and cost of the target deepwater oil and gas fields. Hence, how to design the optimal layout of the cluster manifold is of key importance. This paper will focus on the cluster manifold layout by the math means programmed using C++. For any given subsea well and the floating production system, the basic layout of the cluster manifold with the lowest cost can be obtained based on the assumptions, including the number, locations and cost of the jumpers, PLETS and flowlines. This mathematical method can reduce subjective bias from the engineers and provide a more scientific reference for obtaining the optimal cluster manifold layout.Copyright