Shell is set to ramp up investment activity in its core Trinidad and Tobago east coast natural gas assets over the coming year. The company plans major exploration drilling and seismic campaigns in the east coast acreage, which it obtained as part of the global acquisition of the BG Group last year. 

According to documents submitted in support of its environmental approval application, Shell plans a total of five new exploration wells in acreage close to its existing Dolphin and Dolphin Deep producing reservoirs. The five planned vertical wells will target Pleistocene-aged sandstone deposits, as well as deeper Pliocene-aged sands. The wells will be drilled in water depths ranging from approximately 500-800 feet, with the maximum vertical depth of 20,000 feet. 

Two wells, named Starfish Terrace and Mahi Mahi, will be drilled in block 5(a), in which Chevron holds a 50% non-operator interest. A further two wells, Sharp Horn and Lobster West, will be drilled in block 5(d), with one well, Spine Back, in block 5(c), both 100% owned and operated by Shell. 

Drilling will be conducted by a high specification, semi-submersible drilling rig, which has not yet been contracted. Shell expects the well conditions to be high pressure, but not high temperature. Shell anticipates that any hydrocarbons in the targeted reservoirs will have a high condensate component, in addition to the anticipated natural gas. The exploration programme will include testing of the wells, once commercial hydrocarbons are discovered. 

The drilling programme is expected to commence in Q3 2017, with each well anticipated to take approximately 150 days. Prior to the mobilisation and setting up of the rig on location, a debris clearance and shallow hazard survey will be conducted at each well site to identify any seabed features that need to be considered when anchoring the semisubmersible rig. 

In addition to the planned five well exploration drilling campaign, Shell is also undertaking a major seismic data acquisition campaign across its operated east coast blocks. With an expected investment of US$55 million, the survey will help fulfil Shell’s work programme commitments on the blocks and provide new geological data to allow the company to plan its future exploration and development activity on the blocks. 

Due to kick-start in September 2017, the survey will utilise the same ocean bottom seismic techniques that bpTT successfully employed to give much greater clarity to the geology in its east coast acreage and which led to the decision to progress the Angelin field development. Unlike the traditional seismic data collection technique that utilises streamers towed behind a vessel, the ocean bottom campaign will place nodes on the sea floor to acquire the 3D seismic data. In its environmental clearance application for the survey, Shell says that it anticipates that the ocean bottom techniques will provide much clearer imaging of the sub-surface. 

Shell’s ocean bottom seismic campaign will collect data from across its operated east coast marine acreage, including blocks E, 5(a), 5(c) and 6(b). The survey is expected to take approximately five months, depending on weather conditions.