Jl. Mulyasari II No. 12Bandung 40163 IndonesiaTelp./Faks 022-2009367Email :geoteknik2005@gwgeo.comWebsite: www.gwgeo.com

1

Wednesday, April 16th, 2014

No. : 105/Ext/GW/IV/14Subject : Sarulla Soil Investigation

PT Dwi Agung Sentosa PratamaRuko Regia Boulevard GB / RB2-52Jl. Graha Bintaro - Bintaro JayaTanggerang

Dear Mr. Agung,

Regarding to the soil investigation plan of Sarulla well pad that is proposed by Dyfco,here our comments and recommendations:

1. Based on your information, Dyfco proposed two points of CPT and one point of handbor at each location. In general, CPT and hand bor has penetration limitationespecially hand bor. Maximum CPT penetration depth is about 20.0 m and the testwill be stopped if the manometer reading reached 250.0 kg/cm2. We are unable toobtain information whether the end of the penetration of the stiff lens, boulder, orthe bearing layer. CPT test should be done to obtain the quality of fill construction.

2. Since the limitation of CPT and hand bor, it is highly recommended to conducttechnical drilling combined with standard penetration test (SPT) and undisturbedsampling (UDS). The drilling should be conduct through the existing surface andreach the bearing layer. SPT should be conducted with 1.5 m interval at eachboreholes. From technical drilling the soil stratification and consistency of the projectsite will be obtain.

3. To determined the type and quantity of field testing, additional data are needed asfollows:a) Existing and final topographic maps (cross section included)b) Layout plan of well pad (include location of the drilling rig, mud pond, etc)c) The existing geotechnical investigation data before fill construction conductedd) Laboratory test of fill material (index properties, compaction, and CBR test)

4. To analysis and provide recommendation, additional data are needed as follows:a) Fill construction method of well pad areab) Quality control report during fill construction

Please do not hesitate to contact us if you have any question regarding Sarulla soilinvestigation.

Your sincerely,

Freddy GunawanGW & Associates

Jl. Mulyasari II No. 12Bandung 40163 IndonesiaTelp./Faks 022-2009367Email :geoteknik2005@gwgeo.comWebsite: www.gwgeo.com

1

Wednesday, April 16th, 2014

No. : 105/Ext/GW/IV/14Subject : Sarulla Soil Investigation

PT Dwi Agung Sentosa PratamaRuko Regia Boulevard GB / RB2-52Jl. Graha Bintaro - Bintaro JayaTanggerang

Dear Mr. Agung,

Regarding to the soil investigation plan of Sarulla well pad that is proposed by Dyfco,here our comments and recommendations:

1. Based on your information, Dyfco proposed two points of CPT and one point of handbor at each location. In general, CPT and hand bor has penetration limitationespecially hand bor. Maximum CPT penetration depth is about 20.0 m and the testwill be stopped if the manometer reading reached 250.0 kg/cm2. We are unable toobtain information whether the end of the penetration of the stiff lens, boulder, orthe bearing layer. CPT test should be done to obtain the quality of fill construction.

2. Since the limitation of CPT and hand bor, it is highly recommended to conducttechnical drilling combined with standard penetration test (SPT) and undisturbedsampling (UDS). The drilling should be conduct through the existing surface andreach the bearing layer. SPT should be conducted with 1.5 m interval at eachboreholes. From technical drilling the soil stratification and consistency of the projectsite will be obtain.

3. To determined the type and quantity of field testing, additional data are needed asfollows:a) Existing and final topographic maps (cross section included)b) Layout plan of well pad (include location of the drilling rig, mud pond, etc)c) The existing geotechnical investigation data before fill construction conductedd) Laboratory test of fill material (index properties, compaction, and CBR test)

4. To analysis and provide recommendation, additional data are needed as follows:a) Fill construction method of well pad areab) Quality control report during fill construction

Please do not hesitate to contact us if you have any question regarding Sarulla soilinvestigation.

Your sincerely,

Freddy GunawanGW & Associates

Jl. Mulyasari II No. 12Bandung 40163 IndonesiaTelp./Faks 022-2009367Email :geoteknik2005@gwgeo.comWebsite: www.gwgeo.com

1

Wednesday, April 16th, 2014

No. : 105/Ext/GW/IV/14Subject : Sarulla Soil Investigation

PT Dwi Agung Sentosa PratamaRuko Regia Boulevard GB / RB2-52Jl. Graha Bintaro - Bintaro JayaTanggerang

Dear Mr. Agung,

Regarding to the soil investigation plan of Sarulla well pad that is proposed by Dyfco,here our comments and recommendations:

1. Based on your information, Dyfco proposed two points of CPT and one point of handbor at each location. In general, CPT and hand bor has penetration limitationespecially hand bor. Maximum CPT penetration depth is about 20.0 m and the testwill be stopped if the manometer reading reached 250.0 kg/cm2. We are unable toobtain information whether the end of the penetration of the stiff lens, boulder, orthe bearing layer. CPT test should be done to obtain the quality of fill construction.

2. Since the limitation of CPT and hand bor, it is highly recommended to conducttechnical drilling combined with standard penetration test (SPT) and undisturbedsampling (UDS). The drilling should be conduct through the existing surface andreach the bearing layer. SPT should be conducted with 1.5 m interval at eachboreholes. From technical drilling the soil stratification and consistency of the projectsite will be obtain.

3. To determined the type and quantity of field testing, additional data are needed asfollows:a) Existing and final topographic maps (cross section included)b) Layout plan of well pad (include location of the drilling rig, mud pond, etc)c) The existing geotechnical investigation data before fill construction conductedd) Laboratory test of fill material (index properties, compaction, and CBR test)

4. To analysis and provide recommendation, additional data are needed as follows:a) Fill construction method of well pad areab) Quality control report during fill construction

Please do not hesitate to contact us if you have any question regarding Sarulla soilinvestigation.

Your sincerely,

Freddy GunawanGW & Associates