150
Bottomhole Temperature Total Pump Rate
bbl/min
200 2,000 012,000
Annular Bottomhole Pressure CT Bottomhole Pressure
psi psi
5,000 5,000
in this openhole completion, and the packer setting depth was correlated from this point. After the packer was placed at the oil/water interface, a ball was dropped through the ACTive BHA to initiate setting and expansion of the packer. Specially formulated cement slurry was pumped on top of the packer during the third CT run (left). To restart production, nitrogen pumped in the hole displaced the kill fluids while CT crews moni - tored downhole pressures in real time. Using the ACTive isolation service, Saudi Aramco was able to cut the operation time in half. Water cut decreased from 3,000 bbl/d [477 m3/d] to 1,500 bbl/d [239 m3/d], and oil production increased by 1,000 bbl/d [159 m3/d].
The Future Is Now ∆p = 1,000 psi
> Downhole temperature and pressure. A preliminary run confirmed depth and bottomhole temperature for cement slurry design (left). Real-time differential pressure held steady at 1,000 psi, confirming packer integrity (right).
New measurement capabilities for fiber optics are the focus of several investigations and may come to enhance the array of tools available for CT applications. These measurements will provide advances in production logging capabil - ities and enable monitoring of opera tional parameters for improved BHA performance and longevity. Field experience is already leading to more sophisti cated workflows and intuitive interpre tation software to make the most of the downhole measurements.
Pretreatment distributed temperature sensor (DTS) data showed CT crews where to spot the stimulation acid and the diverting acid, while real-time bottomhole pressure readings provided feedback during the treatment. Once the initial treatment had been pumped, downhole temper - ature readings identified enhanced fluid- injection points and other zones that could be opened up further. Based on analysis of these downhole readings, the operator fine-tuned the diverter and acidizing program and revised the pump schedule for the next stage. The changes allowed temporary diversion of fluid from the initially stimulated zones and provided better overall treatment of each branch of the multilateral (previous page, bottom left). A subsequent DTS survey confirmed that the treatment had successfully diverted the acid to stimulate the remaining targeted zones.
6. Harber B, Stuker J and Pipchuk D: “Improved System for Accessing Multilateral Wells in Canada,” paper SPE 113724, presented at the SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition, The Woodlands, Texas, April 1–2, 2008.
7. Cismoski DA, Rossberg RS, Julian JY, Murphy G, Scarpella D, Zambrano A and Meyer CA: “High-Volume Wellwork Planning and Execution on the North Slope, Alaska,” paper SPE 113955, presented at the SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition, The Woodlands, Texas, April 1–2, 2008.
Reducing Water Cut in Saudi Arabia In Saudi Arabia, the ACTive system was used to revive oil production in a horizontal well with a 60% water cut. The new well, an openhole completion, had been producing oil intermit - tently from a carbonate reservoir. Most of the water was produced from the toe of the well. Saudi Aramco appreciated the complexity of water shutoff operations in this horizontal well. A lack of information about depth, bottomhole temperature and pressure could affect the reliability of high-expansion bridge plugs, cement-plug formulation and placement of isolation devices to shut off the water-producing zone. Saudi Aramco selected ACTive services to provide zonal isolation and reduce water cut without using a workover rig.
The operation deployed a through-tubing inflatable packer on CT, along with a cement plug, to isolate the water-producing zone from the rest of the horizontal wellbore. PTC temperature and pressure measurements obtained during the first run in the hole aided in formulation of a customized cement slurry program. The packer was set in place during the second run in the hole. Real-time readings from the PTC casing collar locator were used to confirm the bottom of casing
Operators are realizing benefits in increased safety and efficiency obtained through moni - toring downhole conditions. Further increases in safety and efficiency will come as more operators monitor these jobs from their own desktops, maintaining their office schedules while reducing their exposure to travel and wellsite risk. This vision is already a reality in some areas. In Alaska, some BP staff monitor job progress by taking advantage of secure real-time data transmissions from the wellsite.7
A standard Web
browser and Internet port connect experts from the BP Anchorage office to approximately 80% of the BP wellsites around Prudhoe Bay. Transmissions to the BP iCenter networked collaborative environment enable Anchorage- based engineers to view data and discuss options with rig personnel. The popularity, and hence the capabilities, of
fiber-optic coiled tubing will continue to grow as this technology expands into a broader range of applications.
— MV
Winter 2008/2009
33
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