| Title | Well Intervention and Enhancement in San Jacinto Geothermal Field, Nicaragua |
|---|---|
| Authors | R.C.M. MALATE, G.N. USSHER, J.U. DACANAY, E.B. DELA PENA, J.N.A. SOUTHON, K. MACKENZIE, J. BROTHERIDGE, M. PEREZ and A.J. DUARTE VALLE |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | well intervention, casing perforation, well forking, San Jacinto Geothermal Project |
| Abstract | The San Jacinto-Tizate Geothermal Field was developed in 2003 by Polaris Energy Nicaragua S.A. (PENSA) under the guidance from Jacobs (formerly Sinclair Knight Merz, SKM). The first 10 MWe back pressure power plant unit was then installed at San Jacinto in 2005. Ram Power Corporation acquired PENSA in 2009 and embarked on the expansion and development of 72 MWe condensing plant at San Jacinto to replace the 10 MWe back pressure unit. The commissioning of the first 36 MWe plant at San Jacinto-Tizate Geothermal Field in January 2012 resulted in some anticipated reservoir pressure drawdown which stabilized after about six months of production. The San Jacinto geothermal reservoir again showed increased pressure drawdown after commissioning of the second 36 MWe plant in December 2012. The decline produced some degradation of steam resource. Jacobs was tasked by Ram Power to develop and implement a production enhancement plan in July 2013 to source out additional steam for San Jacinto. A number of options were identified for this program following a cost-benefit analysis undertaken by Jacobs, including: casing perforation, workovers and forking and deepening of existing wells. This paper discusses the design and operational aspects of the well workover program and well testing, as well as the challenges encountered and solutions implemented for the successful completion of the work activities. Analysis of the downhole measurements after well intervention indicated a notable improvement in wellbore parameters which increased confidence in successfully meeting the targeted output requirements of the two plant units. Horizontal discharge testing of SJ6-1 and SJ6-2 in October 2013 showed modest improvement in their total production output of around 2.5 MWe. Production wells SJ9-3 and SJ12-3 on the other hand showed marked increase in their total production outputs of around 7.5 MWe during horizontal discharge testing. |