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Davies, D.H. (Etudes and Productions Schlumberger) | Faivre, Ollivier (Etudes and Productions Schlumberger) | Gounot, M-T. (Etudes and Productions Schlumberger) | Seeman, Bronislaw (Etudes and Productions Schlumberger) | Trouiller, J-C. (Etudes and Productions Schlumberger) | Benimeli, Dominique (Etudes and Productions Schlumberger) | Ferreira, A.E. (Etudes and Productions Schlumberger) | Pittman, D.J. (Etudes and Productions Schlumberger) | Smits, J-W. (Etudes and Productions Schlumberger) | Randrianavony, Mahaly (Etudes and Productions Schlumberger) | Anderson, B.I. (Schlumberger-Doll Research) | Lovell, John (Schlumberger-Doll Research)
Summary A new generation laterolog tool, the Azimuthal Resistivity Imager (ARI) is described. The tool makes deep azimuthal resistivity measurements around the borehole with higher vertical resolution than the Dual Laterolog (DLL) tool. An array of twelve azimuthal electrodes is incorporated into the dual laterolog array so as to provide twelve deep, oriented resistivity measurements while retaining the standard deep and shallow laterolog measurements. To allow full correction of the azimuthal resistivities for borehole effect, a very shallow auxiliary measurement is incorporated on the azimuthal array. Though the full-coverage azimuthal resistivity image has much lower spatial resolution than borehole micro-electrical images, it complements these because of its lower sensitivity to shallow features. Fracture evaluation and computation of structural dip are applications of the tool's imaging capabilities which are discussed and illustrated with log examples. Other log examples cover thin-bed response, Groningen effect and borehole corrections, including that for eccentering of the tool in the borehole. Introduction The Laterolog technique was introduced in 1951, with the Dual Laterolog tool following some twenty years later. Though instrumentation has been upgraded as technology has developed, the Dual Laterolog deep and shallow measurements, LLd and LLs, have remained essentially unchanged since their introduction. Together with induction tools, the laterolog provides the key input for basic formation evaluation. While important advances have been made in the design of induction devices in the past ten years, few comparable developments have been made in the laterolog domain, despite known limitations to the laterolog measurements. Reference electrode effects have plagued deep laterolog measurements since their early days. Though effects such as Delaware and anti-Delaware effect have been overcome by repositioning the measure and current returns, Groningen effect remains a particularly complex problem which has yet to be satisfactorily resolved. It manifests itself as an increase in the LLd reading in conductive beds overlain by thick, highly resistive beds. The vertical resolution of the deep and shallow laterologs is two to three feet, with a typical beam width of around 28 inches. Thin beds are assuming increasing importance as potential reservoirs, and the vertical resolution of the deep and shallow laterologs is increasingly recognised to be insufficient for adequate evaluation of these beds. Development of a pad-mounted laterolog-3 has reportedly improved vertical resolution to two inches, though a consequence is reduced depth of investigation. Paradoxically, pad or skid devices suffer from a larger borehole effect than cylindrical tools. Though the effect of dip is much less severe than for induction devices, whose responses are perturbed drastically, dual laterolog response is affected significantly across dipping bed boundaries. A directional resistivity measurement around the borehole axis would provide a means of correction for the effects of dip. In one sense such measurements are already available in the form of high-resolution electrical borehole imaging tools, which have been shown to be very effective in evaluation of complex reservoirs.
El Sedeq, Ahmed Zarroug (Schlumberger) | Hughes, Neal (Wintershall DEA) | Oian, Tore (Wintershall DEA) | Byrski, Piotr (Wintershall DEA) | Denichou, Jean-Michel (Schlumberger) | Nketah, Daniel Ndubuisi (Schlumberger) | Dahroug, Mohamed Saher (Schlumberger)
Abstract Dvalin field, discovered in 2010-2012. The location of this field is in the Norwegian Sea, as shown in (Figure 1). Dvalin field is an HPHT gas field in Middle Jurassic sandstone in the Garn and Ile Formations – the former being homogeneous with better reservoir properties, during the later heterogenous with low quality. (DVALIN, 2020) The well 6507/7-Z-2 H objective is to produce hydrocarbons from the Jurassic reservoir section of the Dvalin field safely and cost-effectively. The well was planned to be drilled near vertical in the reservoir section and TD'ed at a maximum depth corresponding to the Garn Formation base. After the productivity results from Z-3-H well came in at the low end of expectations, it was evaluated and decided to change the well profile of the Z-2-H well from vertical reservoir penetration to a horizontal profile; to have two penetrations with a minimum of 150m MD separation in the upper high permeable streak and then drop to penetrate lower high permeable streak. This decision was conducted only three days before starting the 17.5-inch section on the subject well. One Team culture was the key to achieving this significant change successfully. The decision to change the well-profile was conducted after a thorough engineering evaluation, including offset well analysis, which was very limited as the closest horizontal well was more than 40 km away. As the well was not planned as a horizontal well, departure between the surface location and Target Easting & Northing was minimal. Therefore, a high turn and deeper inclination build were required, which added some complexity to the well design. One of the additional primary risks related to this change of trajectory design is deploying a more complex BHA design in the reservoir section with a full suite of LWD technologies run in an HT environment. In the planning phase, special consideration was needed to accurately simulate the expected circulating temperature and have proper procedures in place for temperature management and control. Being the first horizontal well in the field, thus detailed planning was key for successful execution. Ultra-Deep Azimuthal Resistivity Tool (UDAR) Reservoir-Mapping capability was considered to help optimize the landing and navigate within the reservoir section. A feasibility study was conducted, and a 2-receiver Ultra Deep Azimuthal Resistivity Tool BHA configuration was selected and deployed. During the execution, the Ultra Deep Azimuthal Resistivity Tool real-time inversion mapped the reservoir geometry, revealing resistive layers within the Garn formation, thereby facilitating optimal placement of the well to achieve the set objectives. The well execution was largely considered flawless, with the real-time Ultra Deep Azimuthal Resistivity Tool data and corresponding interpretations facilitating decisions.
Zimovets, Sergey (Russian Universal Systems LLC) | Zhylin, Alexandr (Russian Universal Systems LLC) | Zlodeev, Valeriy (Russian Universal Systems LLC) | Kochergin, Maksim (Russian Universal Systems LLC) | Levchenko, Mikhail (Russian Universal Systems LLC) | Zhylin, Anton (Russian Universal Systems LLC) | Vasilyev, Artem (Russian Universal Systems LLC) | Sukharev, Pavel (Russian Universal Systems LLC) | Bardin, Maxim (ISLA LLC)
Since the 80s of the last century, the number of drilled directional wells has been continuously increasing. Inclined and horizontal wells are typically drilled using measurement while drilling (MWD) and logging while drilling (LWD) equipment. This is due to the fact that the depth of productive formations can significantly change, and without the operational control of the well position and the rocks properties in the near wellbore space, there is a high probability that the wellbore will coming out of the productive formation or the well construction is not optimal in terms of oil recovery/gas. Drilling technology with drilling direction correction based on LWD data is called geosteering during drilling. The key LWD method used for geonavigation is electromagnetic logging method, which allows characterization of the surrounding rocks apparent electrical resistivity (ER) distribution.
Al Daghar, Khadija (ADCO) | Ihab, Tarek (ADCO) | Sayed, Raza (ADCO) | Abdelaal, Atef (ADCO) | Ramos, Luis (ADCO) | Chemali, Roland (Halliburton) | Aki, Ahmet (Halliburton) | Azzam, Samer (Halliburton) | Razek, Omar Abdel (Halliburton)
Copyright 2011, Society of Petroleum Engineers This paper was prepared for presentation at the SPE Reservoir Characterisation and Simulation Conference and Exhibition held in Abu Dhabi, UAE, 9-11 October 2011. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright. Abstract In a low-permeability Middle East carbonate reservoir, geologists, petrophysicists, and reservoir and drilling engineers had multiple requirements to optimally place the well, characterize and model fractures and faults, and evaluate the petrophysical attributes and cutoffs of the formation. A suite of logging-while-drilling (LWD) sensors was combined into a single bottomhole assembly (BHA) with the objective of acquiring the information needed to update the static model. An integrated study was then performed using production logs, which led to an improved dynamic model within this sector of the reservoir.
Yuan, Xiyong (School of Geosciences, China University of Petroleum-East China, Qingdao, China) | Deng, Shaogui (School of Geosciences, China University of Petroleum-East China, Qingdao, China) | Wang, Lei (School of Geosciences, China University of Petroleum-East China, Qingdao, China) | Zhang, Pan (School of Geosciences, China University of Petroleum-East China, Qingdao, China)
ABSTRACT Identification and characterization of fractures are critical to the exploration and production of tight reservoirs. This paper introduces a novel multi-array azimuthal resistivity laterolog logging method which can determine fracture position, aperture as well as the dipping angle and strike direction at the borehole level. We studied the responses with different fracture parameters, and numerical results show that amplitude difference among the array resistivity curves is dominated by fracture dipping angle, whereas the azimuthal resistivity are also controlled by fracture dipping direction. The azimuthal resistivity in fracture strike direction is low and the azimuthal resistivity in fracture dipping direction is high. Inclined fractures take on a sine-wave trend in azimuthal resistivity images, which indicates the attitude visually. Furthermore, this method can recognize high-angle fractures around borehole in a considerable distance. A simplified scaled-down experimental instrument was also designed to verify the accuracy of the method. Experimental test shows good consistency with that from numerical results, further indicating the accuracy and feasibility of the proposed method. Presentation Date: Tuesday, October 16, 2018 Start Time: 1:50:00 PM Location: 212A (Anaheim Convention Center) Presentation Type: Oral