The highly reactive FIQA shale used to compel well engineers in The Sultanate of Oman to plan the drilling phase of surface and intermediate sections based on time exposure to aqueous drilling fluid system (WBM). The new approach of drilling the timedependent FIQA shale formation using Casing-while-Drilling (CwD) allows well engineers to plan prospect top/intermediate wellbore sections differently by enhancing the drilling performance and reducing the risk of setting casing strings shallower, external corrosion due to aquifers, and getting stuck or reaming continuosly while drilling conventionally. The technical feasibility study, planning, risk assessment, execution, as well as the lessons learned during the process of drilling top sections are described in this document. The CwD team compares the drilling performance of several offset wells and suggest actions to improve the CwD technology in Oman.Two surface sections were drilled successfully with large OD casing strings. Both surface sections 17½" and 22" reached 750m and 894m measured depth, respectively, reducing drilling phase by 40-45% in comparison with the average in the field. The exposure time of FIQA to aqueous environment was reduced considerably eliminating conditioning trips and non-productive-time (NPT) associated with wellbore instability. The volume of returns as cementing increased from 20% -with conventional drillstring -to 92-98% of pumped excess volume. CwD will allow drilling teams to slim down top holes by drilling/casing much deeper sections within less time preventing FIQA from collapsing and avoiding potential applications of Oil Based Mud (OBM). This new technology may also allow the optimization of existing rigs reducing cost and size of rig prints, as well as minimize HSE risk while handling large-OD casing and extremely heavy DC's.Simulation of the drilling phase using torque/drag and BHA-analysis software were run. The drillable PDC bit performance is compared to bit-records from offset wells recently drilled with conventional BHA's. The effect of CwD on resulting uniform cement sheath (related to the "smear effect") and the reduced size of cuttings at surface which positively aid on preventing flowline plugging as an unplanned event will be described.It is important to highlight that Nonretrievable 17½"x13⅜" and 22"x18⅝" CwD with drillable bit and the casing drive mechanism, did not require any rig modification. The optimization of the process as well as the familiarization of drilling teams with the main components of the CwD system, will lead to a long, demanding scope for its implementation in several fields in Oman.

The first formation testing tools were introduced as wireline tools in the 1950s. Since then, many technological steps were achieved, starting with simple sampling devices adding different measurement technologies in the 1980s up to formation pressure while drilling (FPWD) tools introduced to the field in 2000. Over the last 20 years wireline technology evolved towards high-quality single-phase sampling that also led to the development of the first formation sampling while drilling (FSWD) tools being introduced just over a year ago. In this paper we present a new fluid analysis and sampling tool designed for logging while drilling (LWD) applications. As it is built on the widely proven FPWD technology, it includes all its functionality of optimized testing and seal control. This service operates using a closed-loop control system, integrates real-time downhole analysis of the pressure data, and provides a repeat pressure test with an optimized rate control based on the in-situ derived mobility. This is made possible by the highly accurate pump control system employed. In addition to pressure and mobility capabilities the fluid analysis and sampling tool can analyze and obtain formation fluid samples. The new tool is equipped with high-power pump-out capabilities and highly sophisticated sensors to measure the optical refractive index, the sound speed, the density and the viscosity of the fluid. The innovative pump control prevents alteration of the fluid sample by avoiding pumping below the bubble point. The tool employs the same sample tanks that are used in our wireline tools. The tanks are approved by the Department of Transportation (DOT) for direct transportation of a sample to a certified pressure-volume-temperature (PVT) lab without transferring the sample into another sample bottle. The tool can collect and preserve up to 16 single-phase samples at surface pressures up to 20,000 psi in a single run. It uses a nitrogen buffer system to ensure the suffienct pressure is applied to the sample to prevent alteration. In this paper the capabilities of this new LWD fluid analysis and sampling tool and its first field application on a land rig in Oklahoma are be shown. The field results are compared with a wireline results run to prove the concept of shorter clean-up times while sampling soon after the formation is penetrated by the drill bit. An outlook will be given how to apply this new technology in future applications.

This paper presents the capabilities and operation of a logging-while-drilling (LWD) fluid analysis and sampling tool in a deep-water application in the Gulf of Mexico. The operation was performed during a drilling run in a high-pressure/high-temperature (HPHT) well with an expected downhole pressure of up to 22,000 psi and 300°F downhole temperature. This paper will show how a robust fluid analysis and sampling campaign was planned and executed, matching the various objectives and technical requirements with the appropriate technology. The challenges and opportunities of LWD sampling will be discussed, especially under tough environmental conditions. The advantages of LWD sampling systems are well known, such as shorter pump-out time due to less invasion and the ability to capture reservoir fluid samples in extended reach drilling or highly deviated wells, which provides a new application range compared to current wireline systems. As the harsh drilling environment generates severe shocks and vibration, it requires precaution in the tool design and the selection of suitable components. The influence of the downhole dynamics on the reliability and durability of the system needs to be considered. In response to these challenges, the new LWD tool incorporates an electro-mechanical driven drawdown pump that further improves the LWD fluid analysis and sampling service. This enables a nearly autonomous operation with the assurance that fluid phase integrity is being maintained. Automation allows optimal use of the available bandwidth to deliver the most complete set of fluid property data in real time for efficient decision making, including density, viscosity, sound speed and refractive index. It enables the operator to monitor the fluid identification (fluid ID) trend carefully and in real time, even from remote locations. The sampling process is performed shortly after the hole is drilled and is therefore subjected to different levels of invasion and contamination arising from the effects of the drilling fluid and the reservoir properties. It will be discussed how this effects the clean-up and the ultimately achievable contamination level. The newly introduced compressibility value derived from the electro-mechanical pump offers a bulk measurement, where localized sensors observe scattered data. Examples from the application in the Gulf of Mexico (GOM) will be shown and discussed. An outlook will be given how this technology evolves in future developments and how the operator and oil company can benefit from the new technologies in the drilling environment.

Millions of dollars are spent each year drilling in deepwater areas to prove the presence of hydrocarbons. Wireline formation testers (WFT) are able to capture and retrieve multiple, discreet hydrocarbon discreet hydrocarbon fluid samples at in-situ conditions. Expeditious sample validation once the sample bottles are retrieved at the surface, expeditious sample validation is critical because it provides certainty on sample type and quality. The typical process for well-site wellsite sample validation can be very expensive and high risk because it requires a full laboratory restoration apparatus, a portable lab, and trained personnel to handle high-pressure samples —often under unfavorable conditions. The Advanced Optical Cylinder (AOC) is the latest evolution development in single phase single-phase sampling technology by Baker Hughes. The AOC sample chamber eliminates the high risk and costs associated with sample quality validation in the field and provides costs associated with sample quality validation in the field and provide the clients with very valuable and timely data regarding their fluid sample. The AOC is nitrogen charged sample tank that provides pressure compensation to retrieve a single phase sample and incorporates visible-near infrared (Vis-NIR)technology to obtain spectroscopic measurements of the sample within the tank. The AOC design incorporates nitrogen compensation, to retrieve a single single-phase sample, as well as visible-near infrared (Vis-NIR)technology to obtain spectroscopic measurements of the sample within the tank. The ability to capture Capturing a single single-phase sample is very important because the accuracy of reservoir fluid samples can provide critical parameters needed for optimal completion and production design. Vis-NIR spectroscopy is a well-established tool used for downhole fluid analysis that provides critical information such as fluid type, sample purity and PVT properties. With the AOC, it is now possible to verify the consistency visible-near-infrared spectra of the captured sample of the crude oil or gas obtained during sampling, as soon as the tanks are retrieved at surface without the need for sample transfer. The benefits include avoiding lengthy waiting periods for PVT laboratory analysis, ensuring the quality of retrieved samples, and enhancing critical economic decisions about the reservoir development. The AOC provides the best method for non-invasive sample validation of the captured formation fluid sample, using a high-resolution spectrometer that easily connects to the tank to capture detailed visible and NIR spectra of the pressurized fluid sample. This spectrum can then be compared to the fluid analysis data that was captured while the WFT was sampling, further analysis of the VIS-NIR spectra can determine contamination, GOR, bubble point, and API gravity. Field examples will be used to demonstrate the application and benefits of in-situ sample validation using the AOC.

In the early 2000s, formation pressure while-drilling tools were introduced that can obtain formation pressure data, even in highly deviated wells and extended-reach drilling. In the past two years, this LWD technology has evolved with the addition of downhole fluid sampling and fluid analysis. LWD sampling and testing is now performed in challenging environments that cannot be performed with wireline tools such as horizontal or highly deviated wells. The limitations of wireline deployment in these wells are because of the cumulative frictional resistance of the wireline, the toolstring components and the borehole where it is run. Although several technologies exist to mitigate the risks, such as fly wheels, wireline tractors or pipe-conveyed options, operators prefer to eliminate the risks and costs associated with them by utilizing LWD technology.The first part of this paper describes the new sampling and testing service that was designed for the LWD environment. The service has several closed-loop control systems for pressure testing, mobility determination and pumping during sampling and cleanup operations. In-situ fluid analysis is achieved with sensors that measure optical refractive index, sound speed, density and viscosity. Downhole fluid samples are retrieved with single-phase tank technology.