Publications

The primary carbonates in the KTP field have multiple reservoir targets with different flow units, which are dominantly due to secondary porosity resulting from karstification. These reservoirs are relatively thin with net thicknesses ranging from 10 -30 ft, therefore the amount of producible hydrocarbons will depend on the length of the drain section along the reservoir. A horizontal well was selected in order to have an economical production rate from each of these carbonate reservoirs. There are high uncertainties on the structural dips along the planned lateral length due to limited numbers of offset wells and the reservoir thickness is beyond seismic resolution. In addition, karst has irregular distribution that can pose additional challenges such as directional drilling control, loss circulation and deep mud invasion that affects shallow measurements. To construct an integrated subsurface model of the field, 3D seismic and geological interpretation were utilized to construct a regional scale of 3D geological model. Additionally, LWD reservoir mapping technology via deep directional resistivity provides a reservoir scale image. The integration of reservoir mapping technology and the geological concept of the field resulted in accurate interpretation and therefore the well trajectory was successfully steered within the reservoir. The lateral drain section was maintained successfully with average length of 2600-4000 ft, with 45% length in vuggy connected porosity. The top and bottom reservoir boundaries were mapped continuously during drilling that led to optimum well placement decisions. Due to secondary porosity contribution, the production rate was more than expected.