4. Marathon Oil Consolidates Deepwater Assets. After making a big shale push with a $3.5 billion purchase of KKR ( KKR)-owned Hilcorp Resources and its Eagle Ford shale assets, Marathon is expected to consolidate its deepwater oil exploration portfolio. In a November third quarter earnings release, Marathon said that it would look to sell up to $3 billion in non-core assets - following a spin of its refining and marketing operations now called Marathon Petroleum Company ( MPC) after a June IPO. Separately, Marathon Petroleum announced a sale of its 50% stake in the Seaway Pipeline to Enbridge ( ENB) in its third quarter earnings. Also in November, Bloomberg reported that Marathon Oil was in talks to sell its Angolan offshore operations to Sinopec and other Asian buyers for $800 million, according to two people with knowledge of the process. Reports also indicated that Marathon may look to sell 30% of a joint venture in its Gulf of Mexico deepwater assets for $1 billion to Asian buyers as part of the Houston -based company's announced plans of oil asset sales. Currently, Marathon has a 10% interest in a key deepwater drilling asset offshore of Angola called Block 32, where Total has a 30% interest and the Angolan state-owned oil company Sonangol has a 20% interest. After pursuing an ambitious split of its exploration and downstream assets, to be seen is how Marathon Oil will consolidate its deepwater oil assets as it pushes into shale. 3. Plains All American Pipeline's SemGroup Bid In November, energy pipeline transporter SemGroup ( SEMG) rejected a $24 a share hostile bid by Plains All American Pipeline ( PAA), rebuffing a $1 billion October bid in another crinkle for the multi-year takeover saga. But who's to say all deal talks are off? The bid wasn't the first time Plains made a play at SemGroup, only to see its offer called "opportunistic" and "undervalued." The now quashed hostile bid was a culmination of almost two years of opposition by Plains to SemGroup's recovery strategy from a 2009 bankruptcy and resulting civil litigation with the Securities and Exchanges Commission. In March 2010, Plains offered to buy SemGroup out of bankruptcy for $17 a share. The offer that was rejected by SemGroup's board and company instead went public in November 2010 and priced at over $24 a share on the first day of trading. In August, SemGroup announced it would raise $181 million by doing a public offering of Rose Rock Midstream ( RRMS), which it IPO'ed a 41% stake of in December at $19 a share, raising $140 million. SemGroup also announced a spin of its SemStream businesses to NGL Energy ( NGL) for $279 million in cash in in November. SemGroup's followed its post-bankruptcy planning on its terms - but to be seen is whether spins and continued obstinacy will curtail Plains from making a bid that SemGroup or its shareholders can't refuse.