Modeling of Annular Pressures in Horizontal Directional Drilling

Author(s):  
Samuel T. Ariaratnam ◽  
Richard Stauber ◽  
Bruce Harbin

Horizontal Directional Drilling (HDD) is an established trenchless construction method for the installation of underground utilities and pipelines. Subsequently, the method is becoming widely accepted as a cost-effective alternative to traditional open-cut construction. However, the occurrence of hydraulic fracturing, resulting in the migration of drilling fluid to the surface has placed the HDD process under scrutiny, especially when being considered for environmentally sensitive projects. Hydraulic fracturing results from an excess buildup of fluidic pressure within the borehole. Models have been developed to predict borehole pressures; however, there is limited information available on the relationship between drilling returns and fluid composition to these pressures. A research program was undertaken to model and determine flow characteristics for drilling returns under a variety of soil conditions and bore penetration rates. Nine soil samples were gathered based on the Unified Soil Classification System (USCS) and their respective rheological properties were obtained for different drilling fluids and target slurry densities. This paper presents, as an example, a comparison and analysis of the predicted borehole pressures of clayey-sand (SC) soil in a large directional drill rig application and provides recommendations for contractors when attempting installations in various geological formations. The pressure effects of pipe eccentricity within a borehole were analyzed using a computer model. The result of this research is a simplified approach for predicting downhole fluid pressures for a wide range of project parameters that can be used as a guide to minimize the occurrence of hydraulic fracturing.

Author(s):  
Sheldon Smith ◽  
Shannon Enes ◽  
Jackie Metcalfe ◽  
Rick Guthrie ◽  
Chuck Dubeau

Abstract Open cut has traditionally been the preferred method of pipeline installation traversing watercourses. It is well understood and accepted that open cut excavation of the channel bed and banks during construction causes temporary disturbance to watercourse and aquatic habitat. Horizontal directional drilling, direct push and other subsurface installation methods can potentially avoid channel bed and bank disturbance but may have unique environmental effects such as frac-outs of drilling fluid. Although highly dependent on site conditions, open cut crossings are generally less costly than comparable subsurface installation methods. When a pipeline is installed in an open cut, the pipe is typically installed on a gravel or sand bed, laid in place, surrounded by a sand pack and surrounding soils placed back in the cut in a manner that attempts to replicate the soil lithology, horizons and native compaction of the cut. It has long been thought that this sediment and soil disturbance and backfilling has the potential create a zone of geomorphological weakness at the cut where soil and sediment become dissimilar to the surrounding channel bed and banks and can result in the acceleration of bed scour, bank erosion, widening and slope instability. In this paper we examine the longer-term effects of open cut pipeline installations on the geomorphic characteristics of watercourses. Over the course of four years of field investigation, nearly 750 pipeline watercrossings throughout Ontario were visited and assessed for geomorphic stability and depth of cover. The fluvial geomorphology of Ontario is diverse and ranging from alluvial, sinuous, unconfined, low gradient watercourses in the southwest to karst-influenced morphologies in eastern Ontario and often greater slope, confined and bedrock dominated watercourses in the north. By examining the field-based geomorphological characteristics of pipeline watercourse crossings in Ontario installed by open cut and crossing a wide range of fluvial geomorphological types we will explore and draw empirically-based conclusions on whether open cuts do in fact affect the long term geomorphological conditions of the watercourse.


Author(s):  
Saeed Delara ◽  
Kendra MacKay

Horizontal directional drilling (HDD) has become the preferred method for trenchless pipeline installations. Drilling pressures must be limited and a “no-drill zone” determined to avoid exceeding the strength of surrounding soil and rock. The currently accepted industry method of calculating hydraulic fracturing limiting pressure with application of an arbitrary safety factor contains several assumptions that are often not applicable to specific ground conditions. There is also no standard procedure for safety factor determination, resulting in detrimental impacts on drilling operations. This paper provides an analysis of the standard methods and proposes two alternative analytical models to more accurately determine the hydraulic fracture point and acceptable drilling pressure. These alternative methods provide greater understanding of the interaction between the drilling pressures and the surrounding ground strength properties. This allows for more accurate determination of horizontal directional drilling limitations. A comparison is presented to determine the differences in characteristics and assumptions for each model. The impact of specific soil properties and factors is investigated by means of a sensitivity analysis to determine the most critical soil information for each model.


2021 ◽  
Author(s):  
Mehrdad Gharib Shirangi ◽  
Roger Aragall ◽  
Reza Ettehadi ◽  
Roland May ◽  
Edward Furlong ◽  
...  

Abstract In this work, we present our advances to develop and apply digital twins for drilling fluids and associated wellbore phenomena during drilling operations. A drilling fluid digital twin is a series of interconnected models that incorporate the learning from the past historical data in a wide range of operational settings to determine the fluids properties in realtime operations. From several drilling fluid functionalities and operational parameters, we describe advancements to improve hole cleaning predictions and high-pressure high-temperature (HPHT) rheological properties monitoring. In the hole cleaning application, we consider the Clark and Bickham (1994) approach which requires the prediction of the local fluid velocity above the cuttings bed as a function of operating conditions. We develop accurate computational fluid dynamics (CFD) models to capture the effects of rotation, eccentricity and bed height on local fluid velocities above cuttings bed. We then run 55,000 CFD simulations for a wide range of operational settings to generate training data for machine learning. For rheology monitoring, thousands of lab experiment records are collected as training data for machine learning. In this case, the HPHT rheological properties are determined based on rheological measurement in the American Petroleum Institute (API) condition together with the fluid type and composition data. We compare the results of application of several machine learning algorithms to represent CFD simulations (for hole cleaning application) and lab experiments (for monitoring HPHT rheological properties). Rotating cross-validation method is applied to ensure accurate and robust results. In both cases, models from the Gradient Boosting and the Artificial Neural Network algorithms provided the highest accuracy (about 0.95 in terms of R-squared) for test datasets. With developments presented in this paper, the hole cleaning calculations can be performed more accurately in real-time, and the HPHT rheological properties of drilling fluids can be estimated at the rigsite before performing the lab experiments. These contributions advance digital transformation of drilling operations.


Author(s):  
Denis Pellerin ◽  
Alaide M. Dura˜o ◽  
Jose´ E. F. P. Jardim ◽  
Carlos Pimenta ◽  
Kazumi Miura

The crossing of a series of high, parallel, elongated and with steep scarp mountains in the Serrana Province, between Ca´ceres and Cuiaba´, Mato Grosso State, Brazil, constituted a great technical challenge for implementation of the Bolivia - Mato Grosso gas pipeline. Due to environmental preservation, the gas pipeline could not cross the crest of some of these mountains using conventional surface methods and the alternative of surrounding the mountains would have caused an extended additional path, with appreciable additional cost. The economically viable alternative was the horizontal directional drilling through the most critical mountains: Piraputanga Ridge with 850m, Cachoeirinha Ridge with 943m and Palmeiras Ridge with 867m. One of the difficulties was the drilling of the very compact and abrasive Alto Paraguay Group Proterozoic low metamorphic rocks intercalated with clastic sedimentary rocks. The horizontal directional hole intersects in high angles the strongly dipping layers of rocks. The layered sequences of sandstone capped by siltstones provide the aquifer condition to Raizama Fm. with strong water flow. To prevent any environmental damage, the conventional hole design was modified, which allowed the drilling with water, instead of bentonitic drilling fluid. The horizontal directional drilling consisted of a pilot hole with 10.14 inches diameter, drilled with down hole motor and an electromagnetic steering system. The first enlargement of the pilot hole went to 22” diameter and the last one to 30” using special reamer tools. The pipes of the Bolivia - Mato Grosso gas pipeline have 18” diameter, with a special line coating to prevent damages during pulling in contact with rocks. No problems occurred during the pulling operation of the pipes along the holes. The proposed three horizontal directional holes were very successful and the projected designs of the well were fully achieved, with a very small offset in the forecasted exit points. After long weeks of hole opening and preparatory works, all three pulling operations of the pipestrings along the holes went very smoothly.


2011 ◽  
Vol 287-290 ◽  
pp. 428-431 ◽  
Author(s):  
Ye Fei ◽  
Shu Yang Cong ◽  
Bin Bian

According to the features of heavy horizontal directional drill hydraulic system, power head hydraulic system which is the main working mechanism of the 280t horizontal directional drilling is modeled and simulated base on Amesim. On that basis, we adjust working characteristics of this model and make the point of view that feedback control parameters which is the hydraulic system of heavy drill should be adjusted according to the soil conditions. So that it can enhance the utilization rate of the machine power and drilling efficiency in different operating modes.


Sign in / Sign up

Export Citation Format

Share Document