First Worldwide Application of Continuous Surveys While Drilling Tool Demonstrates Drilling Efficiency, Cost Saving and Well Placement Improvements
Authors: Qahtani Faris A. , Almasmoom Salahaldeen S. , Rahmani Nadhir 
Published: February 2024

Abstract
Drilling Optimization and Project delivery KPIs on unconventional drilling operations are very crucial looking to the need to reduce cost and time to absolute minimum. As part of this journey of optimization surveying time was identified as a major non drilling time and a potential for large savings if reduced or eliminated. That is coupled with connection time which is often including surveying.
Historically, Surveys were acquired on MWD stationary either before or after connection. To Acquire MWD surveys while drilling, the drill string must be stationary without the pipe moving or rotating, the trapped torque must be removed by moving the drill string up and down, and the survey must be pumped to the surface and processed on surface for proper reporting. Similarly, the directional driller must record these surveys on surface and select the best drill string setting for the well to follow the planned well path. This repetitive task takes time, and even if the survey is only done at each joint, the survey time can take days for long/deep wells. Likewise, the time we spend stationary during the survey to perform additional pump cycles on tight landings or to confirm the BHA response on a conventional MWD survey increases the likelihood of drilling risks such as wellbore cleaning, stuck pipe incidents and wellbore washout.
In addition, studies of continuous gyro and conventional continuous MWD inclination surveys have shown that surveying only once per stand can lead to errors in the placement of the wellbore with respect to true vertical depth (TVD). This often leads to a poorer understanding of the true architecture of a well, which can increase the non drilling times during the well construction process to run the casing, complete the well... Non-Drilling Time and Invisible Lost Time represents a significant portion of the authorised expenditure (AFE) for a well, especially given the improvements in well delivery and drilling efficiency achieved in recent years. Definitive Continuous Surveying While Drilling was then introduced to decrease surveying time and improve well placement accuracy. Excessive time was required when using conventional survey techniques, where surveys were taken every 95 ft during connection, and associated weight-to-weight connection time varied from 10 to 15 minutes per stand. This time was needed to free any trapped torque prior to taking survey, recycle pumps, and wait for survey to be transmitted and quality checked on surface. With new Definitive CSWD capability, time was eliminated as this function provides accurate 6-axis surveys continuously while drilling, thereby eliminating all related survey activity steps from operation. The increase in number of surveys obtained while drilling also enhanced well placement and TVD definition for each well drilled.
Introduction of fit-for-purpose Definitive CSWD technology for the first time worldwide, has taken drilling performance to a new level, provided improvement in drilling performance, accuracy in well placement and associated cost reduction. In a short period of time, the drilling performance improved dramatically.