INTELLIGENT WELLS

Optical sensing technology and downhole flow measurement. Nexen Petroleum UK Ltd. used this optical technology on its 13-well project in the North Sea. The optical system consisted of pressure monitoring, Distributed Temperature Sensors (DTS) and downhole flowmeters. The in-well hardware consisted of the flowmeter, the P/T sensor, the optical cable with a pre-integrated dry-mateable optical connector, and cross-coupling cable protectors. The surface data acquisition equipment provided interrogation of sensors and data-handoff to the operators’ Data Management System (DMS). Recorded DTS data allowed optimal selection of gas lift valves.

Triple-zone intelligent well completions. Plains Exploration and Production Company and Chevron successfully completed triple-zone intelligent well completions in its highly-fractured carbonate reservoir in Rocky Point Field offshore California. Working alongside dedicated gauges monitoring pressure and temperature, 3 ½-in. tubing-retrievable flow-control valves control these triple-zone completions, with each zone isolated by multi-port retrievable production packers. This article also describes modifications to intelligent-completion parameters, as well as the feasibility of deploying mandrel-cutting explosive jet cutters by pumping wireline-conveyed assemblies to locator profiles above each packer—to avoid costly deployment of tractors or CT. The effects of the cutting operation on completions components are also discussed.

Dumpflooding, by which fluids from one formation are allowed to flow into another formation, has been used for years in Kuwait to provide reservoir pressure support. As oil production matures, this method has led to reservoir management challenges, including difficulties with flood front control, water breakthrough, conformance management and inability to quantify each well’s crossflow rate. In early 2007, a West Kuwait well was completed as a controlled dumpflood well using intelligent well technology. Using a variable interval control valve, the amount of injection fluid is regulated, while permanent downhole monitoring devices transmit pressure data to surface, enabling evaluation of the flow rate. KOC and WellDynamics tell the story.

 DEEPWATER TECHNOLOGY

A field-proven system for remotely connecting subsea bolted flanges. Deepwater operations in West Africa have required many flowline and pipeline connections, using standard bolted flanges as a cost-effective method for connecting them onshore and offshore. Authors from Acergy will present their experience installing over 100 connections and address the advantages that bolted flanges offer in deepwater flowlines and pipelines, where expansion may be a critical issue.

Riser issues continue to challenge the industry as it produces from fields in ever deeper water. This article will address some of those issues with an example from a recent deepwater installation.

 EXPLORATION

Drilling mud additive potentially effects interpretation of hydrocarbon show. Authors from ConocoPhillips Norge and the University of Oslo determine whether the chemical composition of a frequently used oil-based mud additive has overprinted the hopane signature of an oil-slick sample in a well from the northern North Sea. Overprinting could easily have resulted in erroneous interpretations regarding age and depositional environment of the source rock of the oil. This article demonstrates that if one biomarker group from the mud additive overprints that of the indigenous oil show, this does not preclude other biomarker groups from truly representing the oil show if you know what to do and what to look for.

 GEOLOGY/GEOPHYSICS

Seismic market report. What is it that oil companies want? Are the contractor’s answering their needs, or are they trying to talk them into expensive new services and techniques. What is the health of the “spec” survey market? These are the sorts of questions that we asked oil companies and contractors alike in this report; we have some interesting answers.

Electromagnetics go shallow: the next big thing? All of the major EM contractors have been successful in deepwater. But the technique did not normally work in shallow water. That has changed. By way of “injecting” EM energy and measuring the resistance in different domains, together with the use of some heavy-duty mathematics, many of the obstacles to shallow-water acquisition have been overcome. Now, all off the major EM contractors have developed or recently purchased a shallow water component. This report describes how the various methods work and their current state of use and development.

Mapping alteration caused by hydrocarbon microseepages using image spectroscopy and hyperspectral remote sensing. Using NASA’s Hyperion hyperspectral imaging sensors, this project has developed spectral and geochemical ground truthing techniques to identify and map alterations caused by hydrocarbon micro-seepages and to determine their relationships to the underlying geology in the Patrick Draw area of Southwest Wyoming, the Garza oilfield in Texas and Lisbon valley, Utah. Training the classification of satellite imagery with known spectral inputs from samples resulted in the successful identification of an anomalous zone. Geochemical characteristics of samples that defined this anomalous zone were then compared to the remaining non-anomalous samples using XRD, ICP, spectroscopy and carbon isotope techniques.

 RMOTC

High-resolution seismic on shallow reservoirs. Authors from Brigham Young University and RMOTC demonstrate how high-resolution seismic surveys furnish a clearer picture of shallow reservoirs, as well as of the relationship between deep and shallow faults using Teapot Dome in Wyoming as a test case. High-resolution imaging is important in cases of shallow reservoirs, where understanding compartmentalization of production, fluid communication and continuity of structures is critical.

 ARTIFICIAL LIFT

Part 2 of our popular, annual wrap up on artificial lift systems by our long-standing contributors, Herald Winkler of Texas Tech University, Jim Lea of PL Tech LLC, and Robert Snyder, consultant. This part focuses on the latest developments in electrical submersible pumps (ESPs).

A fail-safe, through-tubing capillary injection system for offshore wells with SCSSV and SSV. Most artificial lift methods to address liquid loading are not applicable offshore due to the regulatory requirements of safety systems such as an SCSSV (Surface Controlled Sub-Surface Safety Valve) and an SSV (Surface Safety Valve), which would be impeded by traditional artificial lift methods. Authors from BJ Services, Chevron and Apache describe a fail-safe, through-tubing capillary injection system that has been applied to two offshore wells having an SCSSV and SSV. The wells maintained full compliance and functionality of the SCSSV by using a specialized WRSCSSV (Wireline-Retrievable Surface Controlled Sub-Surface Safety Valve). The SSV was addressed through the application of a unique wellhead adaptation called a Y-body. These two systems were combined with a capillary foamer injection string that allowed the well to flow at a lower bottomhole pressure.

Pressure transient analysis on ESP lifting wells. Reservoir analysis on wells that are produced using Electrical Submersible Pumps (ESPs) had been a challenge due to downhole equipment restrictions that prevent pressure-transient tests using commonly used acquisition and interpretation methods. During the past few years, the intake pressure acquired using downhole sensors, which is normally used to monitor pump performance, had been used successfully to perform pressure transient analysis on this type of well. This article presents case studies from wells in a field in Ecuador—where production optimization and enhancement opportunities were uncovered as a result of pressure transient analysis using the data gathered during both unscheduled and planned events on wells producing with ESPs. Authors from Schlumberger and operator SIPEC tell the story.

 PRODUCED WATER REPORT

Increasingly, the National Oil Companies hold the majority of the world’s remaining prospects, as well as access to most of the known producing regions. As these NOCs have increasingly been acting as International Oil Companies, the politics and motivation of the NOCs come into play. Do companies like China’s CNOC want to tie up acreage in international arenas to make more money, or is it for strategic, national interests? And how fair is it for a government-backed NOC to compete in the same area as the shareholder-backed IOCs? These and other questions will be explored in our five-page report.