The In Salah Gas Project, Central Algeria: Bringing an Eight Field Gas Development to Sanction

摘要

In Salah Gas is a joint venture between Sonatrach and BP thatrnwill deliver 9 billion cubic metres per annum (bcm/a) fromrneight gas discoveries in the Ahnet-Timimoun Basin of CentralrnAlgeria. Prior to the sanction of this project in early 2000 anrnexploration and appraisal programme was completed to reducernuncertainty in gas volumes and deliverability, prove additionalrnreserves and demonstrate commerciality of the development.rnUncertainties were identified and ranked by quantitativernassessment of alternative appraisal options and their impact onrnproject value (Value of Data analysis). The analysis was usedrnto help define objectives for the exploration and appraisalrnprogramme that comprised acquisition of 2D and 3D seismicrndata plus the drilling of 9 wells.rnKey objectives of the appraisal activity were to assess thernconnectivity of conventional Devonian reservoir intervals,rnevaluate tight gas reservoirs, assess the contribution ofrnfractures to well deliverability and gain an understanding ofrnCarboniferous reservoir distribution using 3-D seismicrnimaging. 4 Extended Well Tests (EWT’s) were a key part ofrnthis programme.rnOptimisation of the exploitation and sequencing of the 7rnfields’ development led to significant cost savings. Arnmodelling tool jointly developed by facilities, wells andrnsubsurface teams ran multiple development options providingrnranked options with deliverability assurance.rnAs part of Sonatrach and BP’s commitment to reducerngreenhouse gas emissions, the vast proportion of producedrnCO2 (400Bcf) will be re-injected at the cost of the project.rnTwo or three dedicated horizontal wells will be drilled torndispose of the CO2 and infrastructure will be put in place tornfacilitate disposal of CO2 from all eight fields.