Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Mathematical Approach of MSE in Thermo-Poro-Elastic Conditions Improves Decision Making to Use RWD
Roohi, Abbas (Montanuniversität Leoben) | Elmgerbi, Asad (Montanuniversität Leoben) | Nascimento, Andreas (Montanuniversität Leoben) | Prohaska, Michael (Montanuniversität Leoben) | Thonhauser, Gerhard (Montanuniversität Leoben)
Abstract Historically Reaming While Drilling (RWD) operations have been restricted to softer formations. The objective in this study is to create a thermoporoelastic model of Mechanical Specific Energy (MSE) for RWD in order to shed important new light on the decision process how to use RWD for a specific formation as well as a recommendation for reamer-pilot size ratio. The analytical approach developed in this paper calculates thermoporoelastic coupled time-dependent stress, pore pressure and temperature variations for an inclined borehole that is drilled through permeable or impermeable formation and which is subjected to far field three dimensional in-situ stresses. Apparent rock strength of the rock in Depth of Cut (DOC) zone beneath the reamer can be determined by using Mohr-Coulomb theory. By using Apparent Rock Strength (ARS) the analytical Mechanical Specific Energy (MSE) can be estimated afterwards. This parameter can be used as a key decision to determine whether a specific formation is a good candidate for RWD or not. A proper combination of pilot and reamer is absolutely critical to optimize bottom hole assembly (BHA) performance and durability. For many years, a trial-and-error technique has been employed by the drilling industry to determine advantages or drawbacks of reamer in the BHA and the optimum reamer-to-pilot-size ratio and bit characteristic for drilling, which requires a significant investment of time and money. The comparison of reamer's MSE, to destroy rock around the wellbore, with bit's MSE, to destroy rock at the bottom of the hole, shows how efficiently reamer can drill rock around the wellbore in certain formation, and in some other formations the drawbacks are outweigh of its advantages. This in turn makes it possible to determine proper formation characteristics to employ reamer in the BHA and also the maximum reamer/bit size ratio for certain rock characteristics in order to support efficient drilling operations. Considering that so fare in the market there is no evidence of a specific model to predict rock strength bellow the reamers, this research and study show its degree of novelty since it propose a model to fill this gap, which can in the future and after tuning be used as a reference application in the petroleum industry for decision making and project cost analysis. Validation in different environments is still to be concluded as a next step in this research.
- North America > United States > Texas (0.28)
- Europe > Norway > Norwegian Sea (0.24)
- Research Report > New Finding (0.48)
- Research Report > Experimental Study (0.34)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.46)
Abstract Coring in unconventional reservoirs with typical unconsolidated formations has introduced additional challenges requiring more innovative concepts to be developed. These requirements, economic issues of unconventional reservoirs, and also issues of conventional coring particularly in regard to excessive trip times incurred have recently led to widespread attention to wireline continuous coring (WCC) modified from mining industry to petroleum industry applications. This coring method has contributed to coring deep formations, long core sections, multiple zones, jam prone formations, exploration zones or areas with unknown core points. Currently, WCC is suffering from several drawbacks while some recent attempts have been made to remove them. In this accordance, this work is missioned to remove some existing defects by adding some innovative concepts to be applied to the ordinary WCC. Therefore, a more efficient continuous coring method is aimed which includes enhanced coring key performance indicators. Therefore, several identified challenges of WCC are considered to be removed or alleviated by innovative concepts to be added. The challenges consist of un-flushed inner tube while run in hole, limited retrievable core size, in-situ/pressure coring hazards (i.e. safety issues, complex sealing, etc.), slick line issues (rig time, torque, rupture, etc.), untimely and inefficient decision making while coring/drilling, non-optimized coring/drilling and tripping induced core damage in WCC. In order to address these issues, as novelty measures, first an inner tube flushing system is proposed for flushing inner tubes prior to commencing coring. Second, casing drilling coring is recommended in order to obtain larger core sizes contributing to improved core analysis. Third, in-situ downhole measurement and sampling systems are proposed to measure properties of in-situ fluids in order to complete or replace pressure/in-situ coring systems and ensure safety. Fourth, an innovative mode conversion system is proposed to mitigate slick line issues. Fifth, a less complex logging while coring system has also been proposed in special cases to enhance and expedite real time decision making process in regard to proceeding to core cutting or not. Sixth, an innovative mode conversion system contributing to partial elimination of wireline jobs will also be proposed to substitute slick line/ wireline retrievals. Seventh, optimum tripping schedules have been characterized as crucial to match formation rock and fluid properties and type of WCC applied and also to prevent coring induced damage.
- Europe > Austria (0.47)
- North America > Canada (0.29)
- North America > United States (0.28)