Sonatrach

About: Sonatrach is a company organization based out in Algiers, Algeria. It is known for research contribution in the topics: Hydraulic fracturing & Structural basin. The organization has 460 authors who have published 494 publications receiving 6339 citations. The organization is also known as: Sonatrach SPA.

Production Gains and Extended Electrical Submersible Pump Run Lives in Harsh Well Conditions

Abstract: Installing ESPs in a reservoir for the first time is always fraught with the uncertainty of achieving economic run lives and this is further amplified in harsh conditions. To mitigate the financial and production risks, sufficient production gains are required to overcome potential short ESP run lives. This paper discusses the results of four pilot ESP wells in Algeria and how infant mortality was eliminated in addition to achieving early production gains. Key to achieving the production gains was candidate selection and well testing to confirm the well productivity and aquifer pressure support. This process also mitigated risk by selecting wells from a reservoir sector with a historical low incidence of asphaltenes and GORs, which have not spiked substantially above solution GOR. Once the ESPs were installed, the production gains were achieved by correctly managing drawdown through real time surveillance, which was also used to manage the stress on the ESP and avoid infant mortality. Longer term run lives was achieved by selecting the correct ESP materials and completion architecture for the well conditions. At the time of writing this paper, none of the four ESPs had failed. The most recent installation had been running for 400 days and the oldest for over 1,300days, which is no small feat when one considers the harsh conditions; a reservoir depth of 10,500 ft TVD with a bottom hole temperature of 245 deg F and a volatile hydrocarbon (41 deg API) with a high GOR. This is compounded by an aquifer with water densities as high as 1.25 due to high salt content, which causes both corrosion and halite scale to form on a regular basis, which was treated with fresh water injection. In two of these wells, net oil production was doubled, but more importantly the recovery factor was substantially increased as the higher ESP drawdown mobilised reserves which would not have been produced with gas lift. Finally, the injection gas saved from converting two wells to ESP was sufficient to complete 4 to 5 new wells with gas lift completions. In terms of technology, the main innovation was the use of an ESP digital twin to monitor ESP health in real time, which was particularly useful in managing the transients associated with slugging. An equally noteworthy take-away was how a holistic approach, which integrated reservoir, completions and production engineering provided seamless management from project definition all the way through to execution.

Lng exports – a contribution to world energy supplies in the decades to come

Abstract: This paper deals with the impact which the development of OPEC gas – in the form of LNG – could have on world energy supplies in the decades to come. In it, the author submits that, merely to stop the wasteful flaring of natural gas, could add over two million barrels per day of oil equivalent to world energy supplies, and that full development of this resource base could increase the figure ten-fold, equivalent to a 60 percent increase in current OPEC oil production levels. And this at a lower cost – in terms of capital expenditure – than alternative new sources of energy. The writer warns that we are now entering a “dangerous period” of two to three years, during which energy supplies will appear to be adequate. This could breed a false sense of security, leading to a delay in making necessary decisions. We must, he says, avoid complacency! In conclusion, he opines that_ exports of OPEC LNG could increase many times over in the coming decades, leading to a massive upsurge in orders for ships, plants, pipelines and so on, which would have a direct, positive impact on the balance of payments of consumer economies. But in order to bring this about, the economic fact of higher energy prices needs to be grasped now and a more equitable burden of risks between producers and consumers worked out.

First application of the cop method to vulnerability mapping in the meffrouch catchment

Abstract: This paper presents the first application of the COP method for the vulnerability mapping in Mefrouch catchment (Tlemcen, Algeria). This method has been developed for the intrinsic vulnerability of carbonates aquifers in the frame of the European COST action 620( Zwahlen 2004 ). It takes into account three factors: the concentration of flow (C factor), the overlaying layers above the water table (O factor) and the precipitation (P factor). Since the method is intended for the karstic medias, it takes into account karst specific characteristics such as swallow holes and sinking streams. The vulnerability map established in this work shows that Meffrouch catchment is composed of five vulnerability classes. The method classifies 27% of the total area of the catchment as zones of high to very high vulnerability. This percentage reveals that anthropic actions can seriously affect the groundwater of the region. In order to prevent pollutants from reaching this vital resource, the established map can be used for the delineation of zones to be protected.