Statistical Analysis Between Different Surveying Instruments to Understand the Reliability of MWD/RSS High Resolution Surveys and its Effect in Well Trajectory Characterization
| Autor: | Marina Ferreira Rego, Leida C. Monterrosa, Erica Zegarra, Ross Lowdon |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Well placement
RSS High resolution 0102 computer and information sciences 02 engineering and technology computer.file_format 01 natural sciences Tortuosity Characterization (materials science) Reliability engineering 020401 chemical engineering 010201 computation theory & mathematics Trajectory Statistical analysis 0204 chemical engineering computer Geology Simulation Reliability (statistics) |
| Zdroj: | Day 3 Thu, March 03, 2016. |
| DOI: | 10.2118/178830-ms |
| Popis: | Industry standard practices for MWD surveying consist in taken the MWD surveys at the connection; this usually will represent 30-m to 40-m interval depending of the drill pipe range used by the operator or drilling contractor. Additionally, in some occasions, the surveying sample is even larger due other drilling operation considerations such as drilling through unstable formations or simply to save rig time by removing the amount of surveys taken in the well trajectory. However, several cases studies had demonstrated that surveying the well path at these intervals is often not enough to capture the real characterization of the well, leading, in some scenarios, to significant errors in the final True Vertical Depth (TVD) placement, less refined reservoir structure interpretation as well as well engineering simulations due the unseen extra tortuosity not applied in the torque and drag analysis. A new technique, using a combination of static MWD or RSS surveys with continuous inclination, provides an engineering approach that allows describing the trajectory at 3-m (10-ft) interval thus reducing the risks aforementioned. This case study aimed to obtain further understanding of wellbore TVD placement and tortuosity characterization by qualifying the accuracy of the 3-m (10-ft) interval High-Resolution Continuous MWD surveys using statistical comparisons against micro-dogleg Continuous North-Seeking gyro listings as well as Dual Inclination analysis between MWD and Rotary Steerable Systems (RSS). TVD error analysis was also taken into account to explore how TVD error modelling can be optimized when considering survey frequency and the use of continuous inclination data in the Ellipses of Uncertainty (EOU) error terms. The results and correlations did not simply ratify the fact that High-Resolution continuous surveys enhance TVD wellbore positioning and well engineering simulations, but more importantly it was possible to demonstrate that the standard deviations between independent surveying instruments at the same sample rate were small and well within the estimate position of uncertainty predicted by the current industry standard error models. Moreover, in order to deliver a more realistic TVD position the findings also outline the need of supplementary case studies with regards TVD error modeling optimization when using continuous data in the description of the well trajectory. Furthermore, this technique represents a step forward in real time decision making process in critical well placement jobs and will also allow drilling operations to be more efficient with reduced operational and HSE risks. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|