OSLO (Reuters) - Norwegian oil and gas investment, a key economic driver, is expected to decline sharply in 2021 after rising less than previously anticipated this year, an industry survey by the national statistics agency (SSB) showed on Thursday.The biggest drop will come in the exploration for new reserves and in spending on development plans, while ongoing oilfield construction work continues largely as expected, the data showed.The closely watched forecasts, based on data from oil..