Echo Energy on 31 August 2018 announced an agreement signed with YPFB that will give it exclusive rights to continue a technical evaluation of the Rio Salado Block in the Tarija Basin for the next year. The work program includes interpreting and integration of three 2D seismic lines acquired in 2015 and 2016, according to the company. At the end of the technical evaluation agreement period, Echo will have the right to negotiate terms for a service contract with YPFB for the block if the company chooses to do so. The acquisition of a working interest in Rio Salado depends on the final commercial terms. Echo on 15 September 2017 announced the award of a seismic reprocessing contract for 3D seismic data on the Huayco and Rio Salado blocks. Echo Energy, on 25 July 2017 announced the signing of a Technical Evaluation Agreement (TEA) for the Rio Salado Block in the Tarija Basin. The TEA contract also included Pluspetrol and YPFB and was signed in Santa Cruz. The Rio Salado Block (502 sq km) includes two dry holes from the early 1960's. An enclave carved from the block includes Huayco Field. The block also includes, according to Echo, the extension of a structure it previously identified. The evaluation study contract gives a company rights to explore the block for a one or two year period but no economic rights for exploration or production and usually carries only a modest investment commitment. However, if initial exploration appears favorable, the company will be given the first option to sign a license contract with a view to drilling exploratory wells and developing production in the areas. 
Echo has signed a LoI with YPFB for a 1-year TEA over the Rio Salado licence area.