Topic: Ultra Deepwater
Topic: Ultra Deepwater
Topic: Ultra Deepwater
OnePetro (http://www.onepetro.org/mslib/app/search.do) is an online database of technical papers from nine technical associations or societies, including SPE and OTC. In searching with the key words “deep water”, it produces over 900 titles in the last three years alone. If it is further restricted by using “deep water” and “Gulf of Mexico” it still produces over 400 titles. Finally, by further restricting the search by changing “deep” to “ultra-deep”, it returns the papers listed below among a number of others.
Close, F., McCavitt, B. and Smith, B., “Deepwater Gulf of Mexico Development Challenges Overview”, SPE 11311, presented at the SPE North Africa Technical Conference & Exhibition, March 12 – 14, Marrakech, Morroco.
This paper describes some of the issues and challenges faced by Chevron, a major player in the deep and ultra-deep GOM, and how they were overcome, as their efforts lead them into progressively deeper water.
Oyeneyin, M.B., “Cost Effective Deepwater Well Construction – A Case for Managed Pressure Drilling with Casing, SPE 123789, presented at Offshore Europe, September 8 – 11, 2009 Aberdeen, U.K.
The increasingly complex temperature and geological features of ultra-deep wells make standard overbalanced drilling difficult as the tolerance between formation pressure, wellbore pressure and the pressure at which the formation fractures becomes quite small. A solution is presented in which the operator drills with casing with an under (managed) pressure fluid.
Rajabi, M.M., Nergaard, A.I., Hole, O. and Vestavik, O.M., “Application of Reelwell Drilling Method from Floating Drilling to Address Related Challenges”, SPE 123953, presented at Asia Pacific Oil and Gas Conference & Exhibition, August 4 – 8, Jakarta, Indonesia.
An alternate solution to the issue cited above in which the window between the formation pressure, wellbore pressure and frac pressure is presented. It is recommended to use a new drilling technology called Reelwell Drilling Method, which is a riserless method by nature and facilitates drilling at any depth by smaller and less expensive floating decks. It also facilitates managed pressure drilling.
Ford, R., Hollek, D., Oynes, C. Smith, B., Khurana, S. and Miller, T., “New Waves in the Gulf of Mexico”, OTC 19259, presented at the Offshore Technology Conference, May 5 – 8, 2008, Houston, Texas.
Drilling in the Gulf of Mexico began to slow down in the 1990s as the major oil companies abandoned the area for bigger targets internationally, leaving it to the independents to develop the smaller fields. However, a new wave of activity has emerged in the last 10 years with the discoveries in ultra-deep water and deep wells in lower tertiary trends in locations pushing the envelope of available technology and infrastructure
Iledare, O., Pincomb, R. and Vitrano, D., “Deepwater Petroleum Exploration and Development in Africa – An Appraisal of Factors, Efforts, and Outcomes”, SPE 128340, presented at the Nigeria Annual International Conference and Exhibition, August 3 – 5, 2009, Abuja, Nigeria.
The deepwater development in Africa is compared and contrasted with other deepwater plays, including the Gulf of Mexico, as regards to supply and demand fundamentals, availability and access, technology and infrastructure innovations, number of fields, flow estimates, average size, completion methods and trends and geopolitics.
Dib, M., Lou, J., Zhu, L. and Bassey, M., “The SBOP Drilling Enables Efficient Drilling in Extreme Water Depths”, OTC 20295, presented at the Offshore Technology Conference, May 4 – 7, 2009.
Drilling with a surface BOP (SBOP) from a Mobil Offshore Drilling Unit (MODU) in offshore basins around the world has been pretty standard since the mid 1990s. With increased interest in the ultra-deep water prospect and subsequent increased demand (and price) of floating rigs, controlling costs becomes increasingly important. It is shown that the SBOP high pressure riser when deployed by an upgraded older generation rig provides a good technical solution while holding costs down.
Karunakaran, D., Lee, D. and Mair, J., “Qualification of the Grouped SLOR Riser System, OTC 19899, presented at the Offshore Technology Conference, May 4 – 7, 2009.
The Grouped Single Line Offset Riser (SLOR) is an open bundle riser solution jointly developed by Subsea 7 and 2H Offshore Engineering Ltd. It is specifically designed to optimize the riser/vessel interface for complex and congested seabed layouts immediately adjacent to production vessels. It uses a buoyant truss frame to guide the SLORs, which constrains all risers to move collectively and thus eliminates the risk of clashing.
Bane, D.E. and Peoples, B., “Subsurface Safety Valve Control System for Ultradeepwater Applications”, OTC 19870, presented at the Offshore Technology Conference, May 4 – 7, 2009.
The conventional subsurface safety valve used in ultra-deep water, high pressure and high temperature applications uses many operational techniques, including pressure-balanced pistons using gas energy for assisted closure, hydraulic balance lines, or a heave spring to insure closure in fail-safe situations. Each has its own risk and reliability issues. A new surface controlled subsurface safety valve (SCSSV) is now available that uses the low opening pressures of a tubing-pressure-insensitive safety valve without gas-charged assisted closure or dual control lines.
Nauduri, S., Nedket, G.H. and Schubert, J.J., “MPD: Beyond Narrow Pressure Windows”, SPE 122276, presented at the IADC/SPE Managed Pressure Drilling and Underbalanced Operations & Exhibition, February 12 – 13, San Antonio, Texas.
Managed Pressure Drilling (MPD) has been employed in the deep and ultra-deep wells in the Gulf of Mexico and elsewhere when the window of pressure between either pore pressure or formation stability and fracture pressure is quite small. But there are other good reasons to utilize MPD including increasing the rate of penetration, reducing ballooning or hole breathing, and reducing formation invasion.
Gruehagen, H. and Lim, D., “Subsea Separation and Boosting”, SPE 123159, presented at the Asia Pacific Oil and Gas Conference & Exhibition, August 4 – 6, 2009, Jakarta, Indonesia.
As drilling is taking place in increasingly deep water, sub-sea processing is being introduced into the industry. Treating the production stream at the sea floor presents opportunities to achieve fore effective deployment of oil and gas reservoirs around the world. It reduces the equipment required on the surface and allows produced water and sand to be reinjected in a closed loop without having to move it to the surface.
Chitale, A.A., Stein, M.H., Arias, B.J., Narayanan, R.K. and Schott, D.W., “A New Methodology to Safely Produce Sand Controlled Wells with Increasing Skin”, SPE 124051, presented at the Asia Pacific Oil and Gas Conference & Exhibition, August 4 – 6, 2009, Jakarta, Indonesia.
Gravel packs for sand control are becoming more common in the deep water Gulf of Mexico. A recent study has shown a 15% failure rate for such completions. It is not unusual for measured skin factor to increase. Typically, when that happens the flow rate is reduced to prevent failure. However, there are other possible causes of the increasing skin. This paper identifies them and calculates the optimum flow rate for these completions.