Marine Technology Reporter Blogs - well

Well stimulation is a well intervention performed on an O & G well to increase production by improving the flow of hydrocarbons from the drainage area into the well bore. The assortment of drilling fluid pumped down the well during drilling and completion can often cause damage to the surrounding formation by entering the reservoir rock and blocking the pore throats (the channels in the rock throughout which the reservoir fluids flow). Similarly, the act of perforating can have a similar effect by jetting debris into the perforation channels. Both these situations reduce the permeability in the near well bore area and so reduce the flow of fluids into the well bore. A simple and safe solution is to pump diluted acid mixtures from surface into the well to dissolve the offending material.

Completion systems are the components necessary to complete a well after it is drilled and prepare it for production. There are a variety of completion options available to oil and gas operators. Cased-hole completion systems, for example, vary from relatively simple single-zone low-pressure/low-temperature (LP/LT) designs to complex high-pressure/high-temperature (HP/HT) applications that are commonly found in deepwater. Cased-hole completion involves running casing or a liner down through the production zone, and cementing it in place. A good cement job is the primary barrier for effective zonal isolation and is the standard industry method to protect the wellbore from unwanted and dangerous influxes of formation fluids, solids and gases.

Oil and Gas drilling teams usually contend with tight schedules for project developments and this may eventually lead to low quality plans and limited risk assessment, which may cause expensive and potentially dangerous drilling problems, such as, stuck pipes, violent kicks, unproductive time and cost overruns. The introduction of Schlumberger’s reservoir mapping-while-drilling service is enabling drillers to make better decisions in short timeframes and avoid costly mistakes. For the operators, the main benefits from the effective well placement may be maximized production, minimized construction and intervention costs. The process of well placements brings together many different disciplines…

The development of pipes that can withstand high pressure, heat and corrosion in deepwater locations such as offshore Brazil and the GoM and WA is continuous. For many years steel piping dominated the O&G industry but with pre-salt projects beyond 2,000 meters deep and corrosive enhanced oil recovery techniques widely being used in the industry, pipeline manufacturers have been looking for more flexible and robust materials. France's Technip, which is a world leader in pipe manufacture, uses layered steel with a stainless steel or plastic lining for main offshore pipes. However, British engineering company Magma Global and Dutch company Airborne are pioneering composite pipes made from a fusion of high-end fibers and plastics which are up to 90% lighter than steel pipes and do not corrode.

Riserless Light Well Intervention (RLWI) enables operators to increase the oil and gas recovery rate from subsea oil wells. It allows rapid well access by using smaller DP vessels instead of larger semisub drilling rigs or drillships. RLWI also enables subsea well intervention without having to use a drilling riser package connected to the subsea stack, which is topped by the blowout preventer system. Riserless intervention is a cost-saving alternative to drilling rigs, reducing mobilization time for life-of-well operations including wireline, logging, light perforating, zone isolation, plug setting and removal, and decommissioning. The technology is based on wireline well maintenance, where the cable is routed via a subsea lubricator system into the subsea well.

The Carcará oilfield off the Brazilian coast is named for a bird of prey that is liberally known as the Brazilian Eagle, its scientic name is: Polyborus Plancus. Carcará located in Block BM-S-8 is believed to hold one of the thickest reservoirs ever discovered in Brazil's Santos Basin pre-salt cluster, with a reservoir thickness of 471 meters. The play is being developed by a consortium composed of Petrobras (66%), Galp Energy (14%), and Brazilian players QGEP and Barra Energia with (10%) each. Tested flow rates and reservoir conditions at the Carcará discovery are superior to the famous Lula field. The Lula field, which is currently producing about 100,000 bopd, is estimated to hold recoverable reserves of between 5 billion and 8 billion boe.

Galp Energy, which is Portugal’s major O&G operator, is aiming at increasing its investments in Brazil through acquisition of new block during Petrobras’ pre-salt bidding round next October. Galp is already considered a preferred partner by Petrobras as can be seen by the fact that Galp currently partners Petrobras in four deepwater pre-salt blocks in the Santos Basin, with the biggest blocks being Lula and Cerambi, both large pre-salt plays, which are producing. Earlier this year Galp again partnered Petrobras in acquiring nine blocks in the Parnaíba, Potiguar and Barreirinhas Basin, during the 11th bidding round which mainly encompassed block along Brazil’s Northeast Coast and Equatorial Margin.

As the time for the first pre-salt bidding round approaches, solid data begins to appear related to production forecasts and assets needed for the field’s development. Brazil’s National Petroleum Agency (ANP) has confirmed that the first pre-salt bidding round will take place in October 2013 in Rio de Janeiro and the rules concerning it have already drawn criticism from potential operators. ANP maintains that these rules will not be changed and has come forth with information concerning the field’s development. According to thr ANP, Libra is expected to produce first oil in 2018, that is, 5 years after the winning consortium signs the E&P contract for Libra. This contract will be signed by November 2013.

With the continued increase in deepwater drilling off the coast of Brazil, it is good to see that Petrobras, Brazil’s national operator, will soon have a well containment device ready for immediate deployment in case of a deepwater blowout such as was experienced in the Deepwater Horizon tragedy at the GoM. According to a Petrobras drilling inspector who prefers to remain anonymous, the Brazilian super-major player believes that their well drilling and completion systems are totally reliable as long as their safety procedures are followed, however, they are taking no chances and have joined forces with other major operators to increase drilling, completion and production safety standards worldwide.

Brazilian national operator Petrobras had a scare with one of its drilling rigs off the coast of the state of Amapé, the northernmost state in Brazil, where the mouth of the Amazon River is located. Although the drilling rig did not completely loose from its mooring anchors, it did tip to one side in such a way that Petrobras was forced to abandon the well. This accident occurred in December 2012 but as yet the well continues plugged. With this development Petrobras was forced to ask the national O&G regulator ANP (National Petroleum Agency) for a longer deadline to be approved for its exploratory plan in the block located at the Amapá coast, in order to better study the very strong currents that occur in this region.

The seabed oil spill that is still ongoing next to the Frade oil field in the Campos Basin is again raising the local awareness to the inherent dangers associated with O&G exploration. As many politicians and environmentalists hit the panic button, this kind of spill is, if not expected, is a definite possibility. There is simply no failsafe way to drill for oil and when the actual drilling is done underwater the risks compounded and the time it takes to resolve the issue is also increased. As this particular spill is a deep water event 1,200 meters deep it may not be so easy to stop and Chevron, the well operator has already taken steps to shut down the well permanently, this may also point to a loss of well control and a possible blowout.

Petrobras has announced it will start producing today the first oil from the pre-salt layer of the Baleia Franca Field, which is located about 85 km from the city of Anchieta (state of Espírito Santo), in the Parque das Baleias area.The Baleia Franca Field´s pre-salt accumulations were discovered in December 2008. The Production will start through the connection of well 6-BFR-1-ESS to the FPSO Capixaba, chartered to Petrobras by SBM and previously operated in the Golfinho Field. Aiming to anticipate the production at the Cachalote and Baleia Franca fields, the platform was moved to Parque das Baleias, after some changes in its process plant. The Baleia Franca pre-salt well will start producing approximately 13,000 bpd of light oil, estimated at 29º API.

New discovery at the Tupi field confirms Tupi potential and another new discovery in an ANP block, to be included in onerous concession contract with Petrobras.In early April 2010 Petrobras Petróleo Brasileiro S.A. announced that it finalized the drilling of another well in the Tupi field which confirms the potential of the pre-salt reservoirs in that field. The new well, 3-BRSA-795-RJS (3-RJS-666), and informally known as Tupi OW, is located in the area of the Tupi Evaluation Plan, at a depth of 2,131 meters, nearly 270 km of the coast of Rio de Janeiro, and 12.5 km northeast of the discovery well, 1-RJS-628 (1-BRSA-369), known as Tupi.

After tests the diverless hot tap proved to be interesting for deep water and shallow water operations.During early August 2009 the world’s first diverless hot tap operation on a pressurised pipeline was performed by Statoil on the Ormen Lange field in the Norwegian Sea. This was the catalyst for the development of the world’s only remote hot tapping machine. “Connecting a pipe to an existing deepwater line would historically mean shutting down and draining the pipeline, cutting into it, adding a special tee spoolpiece and welding it or securing it in place, ensuring the seal is leak-tight. All the water in the pipe would then have to be displaced before the line could come back onstream.