Sophisticated Software Analysis System and Use of Torque/Drag Modeling for Complex Well Operations Increases Operational Efficiency

The calculation of torque and drag in horizontal wells and extended reach wells is an important element in drilling operations, but determining the value of the friction factor is difficult in the calculation of friction. Sichuan Basin constitutes a special gas reservoir system with high pressure and tight formations. They are favorable for gas production which can be accomplished economically only with horizontal drilling and hydraulic fracturing, and Xujiahe Formation is the focus of the exploration and development. In order to determine the reasonable friction factor for directional well and horizontal well in Xujiahe Formation and complete comprehensive evaluation method, both theoretical study on friction mechanism and experimental investigation on friction factor need to be carried out. A series of experiments are conducted for different lithology (sandstone, sand-mudstone, and mudstone), steel, and lubricants (mud systems). The test results are as follows: lubricants have the most obvious influence on the friction coefficient; the friction-reducing effect of the same lubricant on different friction pairs varies; and lubricants have very different effects on the same friction pair. Under the condition of lubrication with clear water, the friction coefficient of rock increases slightly as the normal load rises. Under lubrication with mud, the change range of the friction coefficient of rock with the increase of normal load is low. Rotation speed has limited impact on the friction coefficient. Under the same test condition, the friction coefficient of sandstone is a little higher in the three kinds of rocks. Through a large number of experimental studies, the value range of the friction coefficient of different kinds of rock in the fifth member in Xujiahe Formation is obtained, providing a scientific basis for the drilling design and the calculation of torque and drag in high pressure and tight formations in Sichuan.

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Developing an Efficient Drilling System by Coupling Torque Modelling with Mechanical Specific Energy

Hassan

Al-Majed

Elkatatny

et al. 2018

All Days

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Understanding the formation behavior and the drilling operation is essential to optimize the performance of drilling systems. Several studies were conducted to improve the drilling operation in real time basis utilizing different approaches. Numerous mathematical models (analytical or empirical) were developed to relate the drilling parameters with the rate of penetrations and to predict the drilling efficiency. However, these models are arrived at by ignoring some parameters or employing simplifying assumption(s), which may lead to over or under optimistic drilling performance. The main objective of this research is to investigate the analytical and numerical approaches to calculate the torque and drag in drilling operations and produce a simple and robust model using artificial intelligent techniques. More than 22,000 data point from several wells for depth up to 18,000 ft. was used to develop and validate the model reliability. The full profiles of torque and rate of penetrations was determined, also the required energy for drilling each section has been estimated. The developed model could be utilized to define the optimum range for torque, which leads consequently to generate an efficient drilling system and reduce the drilling cost. In this study, rate of penetration (ROP) was determined using the torque profile and mechanical specific energy (MSE) based on real time and rig-site data. Statistical analysis was conducted to understand the importance of drilling parameters on the variations of torque and rate of penetration. Drilling parameters such as weight on bit (WOB), revolution per minute (RPM), fluid circulation rate (Q), and bit hydraulic horse power (HPb) has been studied. Thereafter, artificial neural network (ANN) model was developed to predict the torque and ROP profiles. The suggested models enable the drilling engineers to optimize the drilling parameters in a real-time manner, by changing the surface and controllable parameters in such a way that maintains the drilling operations within the optimum conditions. This research will assist in improving the operations efficiency through optimizing the drilling parameters. A strong robust model was developed which yields high accuracy results when compared with actual field measurements, average absolute percentage error of less than 6.5% was achieved.

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Sophisticated Software Analysis System and Use of Torque/Drag Modeling for Complex Well Operations Increases Operational Efficiency

Cited by 4 publications

References 11 publications

A Review of Metaheuristic Algorithms for Optimizing 3D Well-Path Designs

A Review of Metaheuristic Algorithms for Optimizing 3D Well-Path Designs

Experimental study of friction coefficient of rocks in high pressure and tight gas reservoirs in Sichuan

Developing an Efficient Drilling System by Coupling Torque Modelling with Mechanical Specific Energy

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