Baosong Ma

Risk Evaluation for Maxi Horizontal Directional Drilling Crossing Projects

Horizontal directional drilling (HDD) has become increasingly used for the construction of large diameter (more than 600 mm or 24 in.) pipeline projects throughout China. Due to the large investment of capital and resources, it is important to conduct a risk evaluation prior to actual construction. However, there are relatively few appropriate analyses or investigations available for such applications. This paper addresses the risk assessment for Maxi HDD projects. The combination of the fuzzy comprehensive evaluation method and analytical hierarchy process was adopted as the basic model. The corresponding risk indices were constructed considering the factors affecting the projects and based on discussions with experts who have conducted HDD crossing projects. Structured judgment matrices and membership matrices were then directly developed from the index systems, and the weight vectors, subordinated vectors, and risk values determined by the use of Matlab software. Finally, the risk level of the projects was obtained by implementing the maximum membership degree law. The synthesis of the fuzzy comprehensive evaluation method and analytical hierarchy process has been demonstrated to provide a theoretical basis for the risk evaluation and establishment of risk control measures for Maxi HDD projects.

Cuttings Transport Mechanism in a Large-Diameter HDD Borehole

AbstractDrilling mud (or drilling fluid) is a vital component in a horizontal directional drilling (HDD) crossing project, for which a key function is the removal of the cuttings from the borehole. The rheological properties of drilling mud, including flow index, consistency index, effective viscosity, and flow patterns, are briefly reviewed. A model of the drilling mud behavior in the annular space is thereby established, based upon which the cuttings transport mechanism is analyzed. In this model, the critical factors for the efficient removal of cuttings are considered to be the rheological properties and return velocity of the drilling mud in the annular space surrounding the drill rod within the hole. The rheological properties should therefore be carefully controlled so the cuttings can be suspended or sink very slowly in the mud, and an appropriate return velocity must be selected so the flow pattern is suitable for effectively transporting the cuttings without compromising the stability of the bor...

China's Municipal Pipelines: Today and Tomorrow

Urbanization in the Peoples Republic of China increased in speed following the initiation of the reform and opening policy. By the end of 2011, the mainland China had a total urban population of 691 million or 51.3% of the total population, rising from 26% in 1990. With the rapid Urbanization, Chinas municipal pipeline is facing a serious challenge and sees a great increase during the 12th Five-Year-Plan period (from 2011 to 2015). This paper will present the status of China’s municipal pipelines (including water, sewer, city gas, etc.) and the government’s plans to improve the municipal pipeline systems, such as new pipeline construction and pipeline rehabilitation, which will bring great business opportunity for the pipeline suppliers and contractors. As well, the research and technical needs to meet the demand of China’s municipal pipeline construction and rehabilitation will be discussed in this paper. STATUS OF CHINA’S MUNICIPAL PIPELINES According to materials, China’s municipal pipelines can be classified into steel pipe, cast iron pipe, concrete pipe, plastic pipe, etc. Steel pipe mainly includes seamless steel pipe, and welded steel pipe. Cast iron pipe mainly includes gray cast iron pipe (common cast iron pipe) and ductile cast iron pipe (nodular cast iron pipe). Concrete pipe mainly includes prestressed concrete pipe (PCP), self-stressing concrete pipe (SPCP), and prestressed concrete cylinder pipe (PCCP), concrete pipe (CP) and reinforced concrete pipe (RCP). Plastic pipe mainly includes: polyethylene pipe (PE) and rigid polyvinyl chloride pipe (PVC-U), etc. Length of municipal pipelines During the 11 th Five-Year-Plan period (from 2006 to 2010), the length of urban water supply pipelines has increased 310,000 kilometers (200,000 miles) nationwide, in which the city’s water supply pipeline length has increased 160,000 kilometers (100,000 miles). And by 2010, urban water supply network length has been up to 1.04 million kilometers (650,000 miles), among which 539,800 kilometers (337,275 miles) of cities water supply network, 159,900 kilometers (100,000 miles) of county water supply network and 335,800 kilometers (209,875 miles) of town’s water

Study on Influence Factors to Application of Large-Scale HDD to Oil and Gas Pipe Installation

Horizontal directional Drilling (HDD) is widely used to install oil and natural gas pipes that have to cross river or lake areas in China. With low-cost, environment friendly, high-efficiency, HDD is recommended as the first alternative of the West-to-East natural gas transmission project. However, there are still lots of technology obstacles around large-scale HDD crossings, especially in gravel-cobble strata, soft-hard combining strata, and water sensitivity strata. In order to deal with these obstacles and find out the critical factors leading to troubles and failures during HDD crossing, this paper analyzes more than 12 cases of oil and gas pipe that were installed by HDD technology. Six normal troubles and seven potential factors will be involved to analyze the relationship between troubles and potential factors.

Preparation and recycling of drilling mud in large scale Horizontal Directional Drilling projects in Mainland China

The preparation and recycling of slurry is a very complicated and crucial task in large Horizontal Directional Drilling (HDD) river-crossing project. This paper introduced the successful and advanced experiences of the utilization and management of slurry in large HDD projects in China. Different property requirements of slurry in different periods of the project are discussed. Research is focused on the recycling system of slurry, including the filtration of slurry which returned from the drill hole, and how to add bentonite and additives in this filtrated slurry. The recycling of slurry can save a large amount of bentonite and additives. The disposal methods of waste mud in the job site were discussed, and two methods were recommended to be adopted to dispose waste mud. One is mechanical methods, using centrifugal machine; the other is chemical method, using chemical material to solidify waste mud.

Research on Safety Evaluation Model of the Main Underground Pipelines in Shanghai, China

With the rapid development of the economy in Shanghai—the metropolis in China, the density of the underground pipelines and the load of the pipeline network are increasing at a high rate. To guarantee the operation of the city properly, safety of Underground Pipeline Network (UPN) must be one of the foremost considerations. In this paper, the authors present a method to assess the UPN safety in Shanghai by applying a newly designed Safety Grade Evaluation Model (SGEM). Furthermore, this paper provides a safety management system, which will optimize management of UPN, by applying a Rehabilitation Cost Model (RCM). At last, the authors design a roadmap for SGEM for future applications. The above models enhance efficient management of pipeline network in Shanghai which will be helpful to rapid development of the city.

Buried Pipe Affected by River Erosion When Crossing the Yangtze River

AbstractTwo river crossing cases are considered in which a pipe is installed beneath the Yangtze River using horizontal directional drilling (HDD). In both cases, a length of pipeline located on the rock strata near the north bank, including a local protrusion, is disrupted by river erosion. A three-dimensional (3D) model is developed to simulate the river erosion based on the finite-element software ABAQUS, which is capable of modeling the properties of the soil and pipelines, as well as their interaction. Results are presented based on an analysis of the stress concentration points at the ends of the rock protrusion, in the vicinity of the erosion. The effect on the pipelines is investigated as a function of the depth, extent, and location of the erosion. The resulting stress and displacement along the crown, spring, and invert lines of the pipelines are shown and compared to the function of the depth, extent, and location. And the stress concentration points occur at the location of rock protrusion and...

Application of UV CIPP in the Sewer Renewal of Baozhou Road in Quanzhou City, China

Based on renewal project of drainage pipes from South Wenling road (Chengdiao) to Baozhou road（Tian an crossing） in Quanzhou City, rehabilitation method of UV CIPP was analyzed. Consideration of impact from temporary drainage to whole drainage system must be taken, and reasonable plans of water plugging and transferring must be chosen. Pipe preprocessing is the key point. Operable processing schemes should be chosen according to different imperfection types. And attention should be paid to summarizing preprocessing methods, developing preprocessing devices and improving the system of preprocessing technology. Besides, quality control system of UV CIPP rehab technology should be completed based on pipe condition and experience in China.

Analysis and Calculation of Jacking Force in the Mudstone Formation

Pipe-jacking is widely used in municipal pipeline installation, and accurate calculation of jacking force is essential for construction design. Various formulas exist to calculate jacking force, which greatly differ in results. Most formulas are based on classical soil mechanics theories and some simplified assumptions that consider friction coefficient between soil and pipes as a fixed value or neglect the effect of slurry thixotropic. Considering the interaction of soil layers, thixotropic slurry and tube wall, friction is consistently changeable during the jacking process; thus, these formulas and theories cannot meet construction demands. This research is based on the Changchun Yitong River drainage pipelines reconstruction project which used slurry balance pipe-jacking machines to handle mudstone geological conditions. The authors used MATLAB to calculate, analyze and compare jacking force with field measured data. Finally, calculation formulas of jacking force and friction force were derived which took mudstone formation and interaction of soil layers, thixotropic slurry and tube wall fully into consideration

Analysis of Borehole Wall Stability in Horizontal Directional Drilling

During horizontal directional drilling, the instability of borehole wall may lead to serious accidents such as too large torque, failure pullback of pipeline, abandonment of bore, etc. Based on the theory of elasticity mechanics and some assumptions, the mechanical model taking into account of initial ground stress and mud pressure is established. Under the practical conditions, cross-section of borehole is noncircular that is mainly caused by the subsidence of reamer. The real cross-section can be equivalent to a series of circles through curve fitting. According to superposition principle and the conversion relationship from polar coordinate system to rectangular coordinate system, the stress formula of noncircular cross-section is given. And then the finite element method is used to calculate and analyze the stress of borehole in the specific engineering. The results show the distribution and variation tendency of stress which can provide some beneficial reference for borehole wall stability study of horizontal directional drilling.