By Ron Bousso

LONDON (Reuters) - Royal Dutch Shell's <RDSa.L> head of exploration Ceri Powell will step down next month, capping seven years in the role marked by sharp cutbacks in the company's search for new oil and gas reserves amid the industry's deep downturn since mid-2014.

Powell, a geologist who joined Shell in 1990 and a vocal supporter for strengthening female involvement in the sector, will depart on February 13 and become managing director of Brunei Shell Petroleum the following month, according to a Shell spokeswoman.

Her departure is part of a broad reshuffle of senior positions following the completion of Shell's $54 billion acquisition of BG Group in February 2016.

Those include the appointment of Jessica Uhl as chief financial officer, who will replace Simon Henry in March as well as the appointment of Gerard Paulides, who oversaw the BG merger, as head of investor relations.

Powell will be replaced by current upstream strategy vice president Marc Gerrits, who started his career in Shell in 1986 as an exploration geologist in Australia.

In an interview with Reuters last month, Powell described Shell's shift away from complex and costly exploration projects in "frontier" areas such as Alaska to areas closer to the company's existing production such as Malaysia and Brunei.

Last year, Shell angered investors when it wrote down $7 billion after failing to find any oil or gas in the Chukchi Sea off Alaska's northwest coast.

This followed years of complex work and a rig accident that drew heavy criticism from environmental activists.

Following the sharp drop in oil prices since mid-2014, Shell slashed its exploration budget to less than $2 billion a year from around $5 billion.

(Reporting by Ron Bousso; editing by Jason Neely)