Drilling & Production

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Given today's economics, a growing percentage of short-life wells – which produce for just three to five years – are being completed as cemented monobores. Such wells are common in the Gulf of Thailand and are prevalent throughout the Asia Pacific region. The concept is also gaining popularity in Canada and in the Gulf of Mexico. The wells are completed in a single trip by running a tubing hanger and a single string of tubing and then cementing through the tubing string and up the annulus. Until now, the cement-through completion process precluded using packers or positive seals. Additionally, because standard gas lift devices do not permit cement-through operations, cemented monobore wells have had no proven method for artificial lift as production decreased.

A key component of this system is a patented side pocket gas lift mandrel. Strategically positioned internal supports and vanes in the cement-tolerant mandrel disrupt fluid flow during cement operations, creating turbulent flow conditions that cause the cement to swirl and prevent it from building up on the fishing neck. The vanes also guide cement wiper plugs through the mandrel and deflect inappropriate running or pulling tools away from the pocket.

Another key component, the CementSafe TRSCSSV, incorporates through-the-flapper equalizing, a wireline-resistant flapper, and puncture communication technology. In addition, an annular piston isolates the spring cavity from wellbore fluids and cement, and the flow tube excludes fluids from the flapper cavity during installation and production.

The system includes a new hydrostatic circulating valve (HCCV), a hydraulically set ZXP liner top packer, dual wiper plugs, and a latch collar. Once the completion has been landed and the packer set, the HCCV is opened via burst disc so excess cement can be circulated out. Pressure applied across the annular sleeve shifts it downward, closing off the ports. A redundant internal insert provides a secondary means of sealing the tubing from the annulus.

Formation pressure tester

Halliburton Energy Services' Sperry-Sun product service line has announced the global commercialization of the GeoTap logging-while-drilling (LWD) forma- tion pressure tester. The LWD sensor provides operators with wireline-quality, reservoir pore pressure data for drilling and formation evaluation applications to help maximize reservoir deliverability.

The formation pressure tester underwent testing with 10 operators worldwide and performed successfully in a variety of lithologies at depths greater than 29,000 ft and with deviations up to 104° inclination.

According to Halliburton, experience gained in the past 18 months has improved formation testing to accurately and precisely measure formation pore pressure during the drilling process.

Direct pore pressure measurements are obtained in 7-10 min using a wireline-type probe and pad and precision quartz pressure sensor. The device allows multiple tests to be performed in a single drilling run with reported accuracy to within 1% of comparable wireline technology. The LWD tester is surface controllable by the Geo-Span real-time/two-way communication downlink system, allowing operators to make on-the-fly decisions regarding the testing program while at the same time communicating reservoir data up hole. Recently, the Geo-Span service successfully operated both the GeoTap LWD formation tester and the Geo-Pilot rotary steerable system in the Gulf of Mexico.

Electric intelligent completion

The world's first deepwater subsea all-electric intelligent completion system has been installed for Petrobras in the Marlim Sul field in the Campos Basin of Brazil. Baker Oil Tools installed the all-electric InCharge system from a DP drilling rig in 3,832 ft of water. The system is permanently tied back to the Petrobras P-40 floating production vessel via a 3.7-mi umbilical. The system can be monitored from any point within Petrobras' internal network.

Petrobras is using this system to remotely monitor the injection of 15,000 to 20,000 b/d of water into the 8-MLS-67HA-RJS well and its distribution between two discrete intervals. The system as deployed includes a cable by-pass expansion joint, retrievable feed-through packer, two flow measurement units, dry-mateable connectors, a single TEC line for power and communication, supervisory surface control system, and two Intelligent Production Regulators.

Petrobras is using the InCode software to monitor and control the system's downhole devices, which include eight QuantX quartz pressure sensors for monitoring tubing and annulus pressure at the IPR valves and internal pressure at the flow measurement units.

The system's deepwater installation represents the culmination of a five-year development project involving Baker Oil Tools, Baker Atlas, Petrobras, and QuantX, a joint venture of Expro International and Baker Hughes established in 2003. Following a rigorous factory acceptance test in Houston, the system was deployed and commissioned in 2001 in a land-based injection well, then remotely controlled and monitored through a satellite link from a surface control system computer located at Petrobras' operational base in the city of Natal, 165 mi from the well site. After 11 months of operation, the system was retrieved from the land well, and then installed in August 2003 in the Marlim Sul well.

The InCharge system monitors real-time measurements of downhole pressure, temperature, and flow in both the tubing and annulus. This enables the operator to manage production and/or injection conditions in real time, and to selectively control individual zonal flow rates, thereby allowing continuous well optimization in response to changing conditions downhole. Flow contribution can be properly allocated, water and gas breakthrough can be controlled, and multiple target zones can be pre-completed to be selectively brought on stream or shut off at will from the PC-based control system.