The search for oil and gas is associated with drilling operations. These drilling activities are associated with many environmental issues such as heavy metal contamination in spent mud. These pose serious health issues to humans when ingested or inhaled. Spent mud contaminated with heavy metals are also toxic to marine organisms if disposed into the sea untreated. Adsorption has been investigated as a cost-effective method of removal of heavy metals from wastewater. In the present study low-cost local rice husk adsorbent was used to treat spent synthetic mud to treat four major heavy metals (Cadmium, Lead, Arsenic and Mercury). Samples of spent mud were collected from the Jubilee Field in Ghana and were digested and analysed using the Atomic Absorption Spectrometer (AAS). With local rice husk adsorbent concentrations of 10, 20 and 40 mg/l, mixing speed of 200 to 259 rpm, contact time from 20 to 30 minutes, and comparing with EPA standards, Cadmium recorded improvement from -1 168% to 59%, Lead was improved from -633% to 20%, Arsenic was improved from -4050% to -440%, Mercury recorded improvement from -200% to 80%. Metals like Cadmium, Lead and Mercury residual concentrations were able to meet global limits for effluent disposal, but Arsenic was not and may therefore require more contact time to meet global limits for effluent disposal.